Rushing to Judgment (Global Warming Questioned

Is Earth warming? The planet has warmed since the mid-1800s, but before that it cooled for more than five centuries. Cycles of warming and cooling have been part of Earth’s natural climate history for millions of years. So what is the global warming debate about? It’s about the proposition that human use of fossil fuels has contributed significantly to the past century’s warming, and that expected future warming may have catastrophic global consequences. But hard evidence for this human contribution simply does not exist; the evidence we have is suggestive at best. Does that mean the human effects are not occurring? Not necessarily. But media coverage of global warming has been so alarmist that it fails to convey how flimsy the evidence really is. Most people don’t realize that many strong statements about a human contribution to global warming are based more on politics than on science. Indeed, the climate change issue has become so highly politicized that its scientific and political aspects are now almost indistinguishable. The United Nations Intergovernmental Panel on Climate Change (IPCC), upon which governments everywhere have depended for the best scientific information, has been transformed from a bona fide effort in international scientific cooperation into what one of its leading participants terms “a hybrid scientific/political organization.”

Yet apart from the overheated politics, climate change remains a fascinating and important scientific subject. Climate dynamics and climate history are extraordinarily complex, and despite intensive study for decades, scientists are not yet able to explain satisfactorily such basic phenomena as extreme weather events (hurricanes, tornadoes, droughts), El Niño variations, historical climate cycles, and trends of atmospheric temperatures. The scientific uncertainties about all these matters are great, and not surprisingly, competent scientists disagree in their interpretations of what is and is not known. In the current politicized atmosphere, however, legitimate scientific differences about climate change have been lost in the noise of politics.

For some, global warming has become the ultimate symbol of pessimism about the environmental future. Writer Bill McKibben, for example, says, “If we had to pick one problem to obsess about over the next 50 years, we’d do well to make it carbon dioxide.” I believe that we’d be far wiser to obsess about poverty than about carbon dioxide.

Fossil fuels (coal, oil, and natural gas) are the major culprits of the global warming controversy and happen also to be the principal energy sources for both rich and poor countries. Governments of the industrial countries have generally accepted the position, promoted by the IPCC, that humankind’s use of fossil fuels is a major contributor to global warming, and in 1997 they forged an international agreement (the Kyoto Climate Change Protocol) mandating that worldwide fossil fuel use be drastically reduced as a precaution against future warming. In contrast, the developing nations for the most part do not accept global warming as a high-priority issue and, as yet, are not subject to the Kyoto agreement. Thus, the affluent nations and the developing nations have set themselves on a collision course over environmental policy relating to fossil fuel use.

The debate about global warming focuses on carbon dioxide, a gas emitted into the atmosphere when fossil fuels are burned. Environmentalists generally label carbon dioxide as a pollutant; the Sierra Club, for example, in referring to carbon dioxide, states that “we are choking our planet in a cloud of this pollution.” But to introduce the term pollution in this context is misleading because carbon dioxide is neither scientifically nor legally considered a pollutant. Though present in Earth’s atmosphere in small amounts, carbon dioxide plays an essential role in maintaining life and as part of Earth’s temperature control system.

Those who have had the pleasure of an elementary chemistry course will recall that carbon dioxide is one of the two main products of the combustion in air of any fossil fuel, the other being water. These products are generally emitted into the atmosphere, no matter whether the combustion takes place in power plants, household gas stoves and heaters, manufacturing facilities, automobiles, or other sources. The core scientific issue of the global warming debate is the extent to which atmospheric carbon dioxide from fossil fuel burning affects global climate.

When residing in the atmosphere, carbon dioxide and water vapor are called “greenhouse gases,” so named because they trap some of Earth’s heat in the same way that the glass canopy of a greenhouse prevents some of its internal heat from escaping, thereby warming the interior of the greenhouse. By this type of heating, greenhouse gases occurring naturally in the atmosphere perform a critical function. In fact, without greenhouse gases Earth would be too cold, all water on the planet would be frozen, and life as we know it would never have developed. In addition to its role in greenhouse warming, carbon dioxide is essential for plant physiology; without it, all plant life would die.

A number of greenhouse gases other than carbon dioxide and water vapor occur naturally in Earth’s atmosphere and have been there for millennia. What’s new is that during the industrial era, humankind’s burning of fossil fuels has been adding carbon dioxide to the atmospheric mix of greenhouse gases over and above the amounts naturally present. The preindustrial level of 287 parts per million (ppm) of carbon dioxide in the atmosphere has increased almost 30 percent, to 367 ppm (as of 1998).

Few, if any, scientists question the measurements showing that atmospheric carbon dioxide has increased by almost a third. Nor do most scientists question that humans are the cause of most or all of the carbon dioxide increase. Yet the media continually point to these two facts as the major evidence that humans are causing the global warming Earth has recently experienced. The weak link in this argument is that empirical science has not established an unambiguous connection between the carbon dioxide increase and the observed global warming. The real scientific controversy about global warming is not about the presence of additional carbon dioxide in the atmosphere from human activities, which is well established, but about the extent to which that additional carbon dioxide affects climate, now or in the future.

Earth’s climate is constantly changing from natural causes that, for the most part, are not understood. How are we to distinguish the human contribution, which may be very small, from the natural contribution, which may be small or large? Put another way, is the additional carbon dioxide humans are adding to the atmosphere likely to have a measurable effect on global temperature, which is in any case changing continually from natural causes? Or is the temperature effect from the additional carbon dioxide likely to be imperceptible, and therefore unimportant as a practical matter?

Global warming is not something that happened only recently. In Earth’s long history, climate change is the rule rather than the exception, and studies of Earth’s temperature record going back a million years clearly reveal a number of climate cycles—warming and cooling trends. Their causes are multiple—possibly including periodic changes in solar output and variations in Earth’s tilt and orbit—but poorly understood. In recent times, Earth entered a warming period. From thermometer records, we know that the air at Earth’s surface warmed about 0.6ºC over the period from the 1860s to the present. The observed warming, however, does not correlate well with the growth in fossil fuel use during that period. About half of the observed warming took place before 1940, though it was only after 1940 that the amounts of greenhouse gases produced by fossil fuel burning rose rapidly, as a result of the heavy industrial expansions of World War II and the postwar boom (80 percent of the carbon dioxide from human activities was added to the air after 1940).

Surprisingly, from about 1940 until about 1980, during a period of rapid increase in fossil fuel burning, global surface temperatures actually displayed a slight cooling trend rather than an acceleration of the warming trend that would have been expected from greenhouse gases. During the 1970s some scientists even became concerned about the possibility of a new ice age from an extended period of global cooling (a report of the U.S. National Academy of Sciences reflected that concern). Physicist Freeman Dyson notes that “the onset of the next ice age [would be] a far more severe catastrophe than anything associated with warming.”

Earth’s cooling trend did not continue beyond 1980, but neither has there been an unambiguous warming trend. Since 1980, precise temperature measurements have been made in Earth’s atmosphere and on its surface, but the results do not agree. The surface air measurements indicate significant warming (0.25 to 0.4ºC), but the atmospheric measurements show very little, if any, warming.

Briefly, then, the record is this: From 1860 to 1940, Earth’s surface warmed about 0.4ºC. Then Earth’s surface cooled about 0.1ºC in the first four decades after 1940 and warmed about 0.3ºC in the next two. For those two most recent decades, temperature measurements of the atmosphere have also been available, and, while these measurements are subject to significant uncertainty, they indicate that the atmosphere’s temperature has remained essentially unchanged. Thus, the actual temperature record does not support the claims widely found in environmental literature and the media that Earth has been steadily warming over the past century. (A new study that may shed more light on this question—one of a number sure to come—has been circulated but is being revised and has not yet been published.)

For the probable disparity between the surface and atmospheric temperature trends of the past 20 years, several explanations have been offered. The first is that large urban centers create artificial heating zones—“heat islands”—that can contribute to an increase of surface temperature (though one analysis concludes that the heat island effect is too small to explain the discrepancy fully). The second explanation is that soot and dust from volcanic eruptions may have contributed to cooling of the atmosphere by blocking the Sun’s heat (though this cooling should have affected both surface and atmospheric temperatures). In the United States, despite the presence of large urban areas, surface cooling after 1930 far exceeded that of Earth as a whole, and the surface temperature has subsequently warmed only to the level of the 1930s.

It’s frequently claimed that the recent increases in surface temperature are uniquely hazardous to Earth’s ecosystems because of the rapidity with which they are occurring—more than 0.1ºC in a decade. That may be true, but some past climate changes were rapid as well. For example, around 14,700 years ago, temperatures in Greenland apparently jumped 5ºC in less than 20 years—almost three times the warming from greenhouse gases predicted to occur in this entire century by the most pessimistic scientists.

Whatever the current rate of surface warming, there is little justification for the view that Earth’s climate should be unchanging, and that any climate change now occurring must have been caused by humans and should therefore be fixed by humans. In fact, as noted earlier, changing climate patterns and cycles have occurred throughout Earth’s history. For millions of years, ice sheets regularly waxed and waned as global heating and cooling processes took place. During the most recent ice age, some 50,000 years ago, ice sheets covered much of North America, northern Europe, and northern Asia. About 12,000 years ago a warming trend began, signaling the start of an interglacial period that continues to this day. This warm period may have peaked 5,000 to 6,000 years ago, when global ice melting accelerated and global temperatures became higher than today’s. Interglacial periods are thought to persist for about 10,000 years, so the next ice age may be coming soon—that is, in 500 to 1,000 years.

Within the current interglacial period, smaller cyclic patterns have emerged. In the most recent millennium, several cycles occurred during which Earth alternately warmed and cooled. There’s evidence for an unusually warm period over at least parts of the globe from the end of the first millennium to about 1300. A mild climate in the Northern Hemisphere during those centuries probably facilitated the migration of Scandinavian peoples to Greenland and Iceland, as well as their first landing on the North American continent, just after 1000. The settlements in Greenland and Iceland thrived for several hundred years but eventually were abandoned when the climate turned colder, after about 1450. The cold period, which lasted until the late 1800s, is often called the Little Ice Age. Agricultural productivity fell, and the mass exodus to North America of many Europeans is attributed at least in part to catastrophic crop failures such as the potato famine in Ireland.

A plausible interpretation of most or all of the observed surface warming over the past century is that Earth is in the process of coming out of the Little Ice Age cold cycle that began 600 years ago. The current warming trend could last for centuries, until the expected arrival of the next ice age, or it could be punctuated by transient warm and cold periods, as were experienced in the recent millennium.

A great deal of global warming rhetoric gives the impression that science has established beyond doubt that the recent warming is mostly due to human activities. But that has not been established. Though human use of fossil fuels might contribute to global warming in the future, there’s no hard scientific evidence that it is already doing so, and the difficulty of establishing a human contribution by empirical observation is formidable. One would need to detect a very small amount of warming caused by human activity in the presence of a much larger background of naturally occurring climate change—a search for the proverbial needle in a haystack.

Still, understanding climate change is by no means beyond science’s reach, and research is proceeding in several complementary ways. Paleoclimatologists have been probing Earth’s past climatic changes and are uncovering exciting new information about Earth’s climate history going back thousands, and even millions, of years. This paleohistory will help eventually to produce a definitive picture of Earth’s evolving climate, and help in turn to clarify the climate changes we’re experiencing in our own era. But we are far from knowing enough to be able to predict what the future may hold for Earth’s climate.

Mindful of the limited empirical knowledge about climate, some climate scientists have been attempting to understand possible future changes by using computer modeling techniques. By running several scenarios, the modelers obtain a set of theoretical projections of how global temperature might change in the future in response to assumed inputs, governed mainly by the levels of fossil fuel use. But like all computer modeling, even state-of-the-art climate modeling has significant limitations. For example, the current models cannot simulate the natural variability of climate over century-long time periods. A further major shortcoming is that they project only gradual climate change, whereas the most serious impacts of climate change could come about from abrupt changes. (A simple analogy is to the abrupt formation of frost, causing leaf damage and plant death, when the ambient air temperature gradually dips below the freezing point.) Given the shortcomings, policymakers should exercise considerable caution in using current climate models as quantitative indicators of future global warming.

Scientists have long been aware that physical factors other than greenhouse gases can influence atmospheric temperature. Among the most important are aerosols—tiny particles (sulfates, black carbon, organic compounds, and so forth) introduced into the atmosphere by a variety of pollution sources, including automobiles and coal-burning electricity generators, as well as by natural sources such as sea spray and desert dust. Some aerosols, such as black carbon, normally contribute to heating of the atmosphere because they absorb the Sun’s heat (though black carbon aerosols residing at high altitudes can actually cool Earth’s surface because they block the Sun’s rays from getting through to it). Other aerosols, composed of sulfates and organic compounds, cool the atmosphere because they reflect or scatter the Sun’s rays away from Earth. Current evidence indicates that aerosols may be responsible for cooling effects at Earth’s surface and warming effects in Earth’s atmosphere. But the impacts of pollution on Earth’s climate are very uncertain. The factors involved are difficult to simulate, but they must be included in computer models if the models are to be useful indicators of future climate. When climate models are finally able to incorporate the full complexity of pollution effects, especially from aerosols, the projected global temperature change could be either higher or lower than current projections, depending on the chemistry, altitude, and geographic region of the particular aerosols involved. Or, it could even be zero.

In addition to pollution, other physical factors that can influence surface and atmospheric temperature are methane (another greenhouse gas), dust from volcanic activity, and changes in cloud cover, ocean circulation patterns, air-sea interactions, and the Sun’s energy output. “The forcings that drive long-term climate change,” concludes James Hansen, one of the pioneers of climate change science, “are not known with an accuracy sufficient to define future climate change. Anthropogenic greenhouse gases, which are well measured, cause a strong positive forcing [warming]. But other, poorly measured, anthropogenic forcings, especially changes of atmospheric aerosols, clouds, and land-use patterns, cause a negative forcing that tends to offset greenhouse warming.” And as if the physical factors were not challenging enough, the inherent complexity of the climate system will always be present to thwart attempts to predict future climate.

In view of climate’s complexity and the limitations of today’s climate simulations, one might expect that pronouncements as to human culpability for climate change would be made with considerable circumspection, especially pronouncements made in the name of the scientific community. So it was disturbing to many scientists that a summary report of the IPCC issued in 1996 contained the assertion that “the balance of evidence suggests a discernible climate change due to human activities.” The latest IPCC report (2001) goes even further, claiming that “there is new and stronger evidence that most of the warming observed over the last 50 years is attributable to human activities.” But most of this evidence comes from new computer simulations and does not satisfactorily address either the disparity in the empirical temperature record between surface and atmosphere or the large uncertainties in the contributions of aerosols and other factors. A report issued by the National Academy of Sciences in 2001 says this about the model simulations:

Because of the large and still uncertain level of natural variability inherent in the climate record and the uncertainties in the time histories of the various forcing agents (and presumably aerosols), a causal linkage between the buildup of greenhouse gases in the atmosphere and the observed climate changes during the 20th century cannot be unequivocally established. The fact that the magnitude of the observed warming is large in comparison to natural variability as simulated in climate models is suggestive of such a linkage, but it does not constitute proof of one because the model simulations could be deficient in natural variability on the decadal to century time scale.

These IPCC reports have been adopted as the centerpiece of most current popularizations of global warming in the media and in the environmental literature, and their political impact has been enormous. The 1996 report was the principal basis for government climate policy in most industrial countries, including the United States. The IPCC advised in the report that drastic reductions in the burning of fossil fuels would be required to avoid a disastrous global temperature increase. That advice was the driving force behind the adoption in 1997 of the Kyoto protocol to reduce carbon dioxide emissions in the near future.

In its original form, the protocol had many flaws. First, it exempted developing countries, including China, India, and Brazil, from the emission cutbacks; such countries are increasingly dependent on fossil fuels, and their current greenhouse gas emissions already exceed those of the developed countries. Second, it mandated short-term reductions in fossil fuel use to reach the emission targets without regard to the costs of achieving those targets. Forced cutbacks in fossil fuel use could have severe economic consequences for industrial countries (the protocol would require the United States to cut back its fossil fuel combustion by over 30 percent to reach the targeted reduction of carbon dioxide emissions by 2010), and even greater consequences for poor countries should they ultimately agree to be included in the emissions targets. The costs of the cutbacks would have to be paid up front, whereas the assumed benefits would come only many decades later. Third, the fossil fuel cutbacks mandated by the protocol are too small to be effective—averting, by one estimate, only 0.06ºC of global warming by 2050.

The Kyoto protocol was signed in 1997 by many industrial countries, including the United States, but to have legal status, it must be ratified by nations that together account for 55 percent of global greenhouse gas emissions. As of June 2002, the protocol had been ratified by 73 countries, including Japan and all 15 nations of the European Union. These countries are responsible, in all, for only 36 percent of emissions, but the 55 percent requirement may be met by Russia’s expected ratification. Nonetheless, the treaty is unlikely to have real force without ratification by the United States. The Bush administration opposes the treaty, on the grounds of its likely negative economic impact on America, and has thus far not sought Senate ratification. Even the Clinton administration did not seek ratification, despite its having signed the initial protocol, because it was aware that the U.S. Senate had unanimously adopted a resolution rejecting in principle any climate change treaty that does not include meaningful participation by developing countries.

With the United States retaining its lone dissent, 165 nations agreed in November 2001 to a modified version of Kyoto that would ease the task of reducing carbon dioxide emissions by allowing nations to trade their rights to emit carbon dioxide, and by giving nations credit for the expansion of forests and farmland, which soak up carbon dioxide from the atmosphere. A study by economist William Nordhaus in Science magazine (Nov. 9, 2001) finds that a Kyoto treaty modified along these lines would incur substantial costs, bring little progress toward its objective, and, because of the huge fund transfers that would result from the practice of emissions trading, stir political disputes. Nordhaus concludes that participation in the treaty would have cost the United States some $2.3 trillion over the coming decades—more than twice the combined cost to all other participants. It does not require sympathy with overall U.S. climate change policy to understand the nation’s reluctance to be so unequal a partner in the Kyoto enterprise.

Though the political controversy continues, the science has moved away from its earlier narrow focus on carbon dioxide as a predictor of global warming to an increasing realization that the world’s future climate is likely to be determined by a changing mix of complex and countervailing factors, many of which are not under human control and all of which are insufficiently understood. But regardless of the causes, we do know that Earth’s surface has warmed during the past century. Although we don’t know the extent to which it will warm in the future, or whether it will warm at all, we can’t help but ask a couple of critical questions: How much does global warming matter? What would be the consequences if the global average temperature did actually rise during the current century by, say, some 2ºC?

Some environmentalists have predicted dire consequences from the warming, including extremes of weather, the loss of agricultural productivity, a destructive rise in sea level, and the spread of diseases. Activists press for international commitments much stronger than the Kyoto protocol to reduce the combustion of fossil fuels, and they justify the measures as precautionary. Others counter that the social and economic impacts of forced reductions in fossil fuel use would be more serious than the effects of a temperature rise, which could be small, or even beneficial.

Although the debate over human impacts on climate probably won’t be resolved for decades, a case can be made for adopting a less alarmist view of a warmer world. In any event, the warmer world is already here. In the past 2,500 years, global temperatures have varied by more than 3ºC, and some of the changes have been much more abrupt than the gradual changes projected by the IPCC. During all of recorded history, humans have survived and prospered in climate zones far more different from one another than those that might result from the changes in global temperatures now being discussed.

Those who predict agricultural losses from a warmer climate have most likely got it backwards. Warm periods have historically benefited the development of civilization, and cold periods have been detrimental. For example, the Medieval Warm Period, from about 900 to 1300, facilitated the Viking settlement of Iceland and Greenland, whereas the subsequent Little Ice Age led to crop failures, famines, and disease. Even a small temperature increase brings a longer and more frost-free growing season—an advantage for many farmers, especially those in large, cold countries such as Russia and Canada. Agronomists know that the enrichment of atmospheric carbon dioxide stimulates plant growth and development in greenhouses; such enrichment at the global level might be expected to increase vegetative and biological productivity and water-use efficiency. Studies of the issue from an economic perspective have reached the same conclusion: that moderate global warming would most likely produce net economic benefits, especially for the agriculture and forestry sectors. Of course, such projections are subject to great uncertainty and cannot exclude the possibility that unexpected negative impacts would occur.

As for the concern that warmer temperatures would spread insect-borne diseases such as malaria, dengue fever, and yellow fever, there’s no solid evidence to support it. Although the spread of disease is a complex matter, the main carriers of these diseases—which were common in North America, western Europe, and Russia during the 19th century, when the world was colder than it is today—are most likely humans traveling the globe and insects traveling with people and goods. The strongest ally against future disease is surely not a cold climate but concerted improvement in regional insect control, water quality, and public health. As poverty recedes and people’s living conditions improve in the developing world, the level of disease, and its spread, can be expected to decrease. Paul Reiter, a specialist in insect-borne diseases, puts it this way:

Insect-borne diseases are not diseases of climate but of poverty. Whatever the climate, developing countries will remain at risk until they acquire window screens, air conditioning, modern medicine, and other amenities most Americans take for granted. As a matter of social policy, the best precaution is to improve living standards in general and health infrastructures in particular.

One of the direst (and most highly publicized) predictions of global warming theorists is that greenhouse gas warming will cause sea level to rise and that, as a result, many oceanic islands and lowland areas, such as Bangladesh, may be submerged. But in fact, sea level—which once was low enough to expose a land bridge between Siberia and Alaska—is rising now, and has been rising for thousands of years. Recent analyses suggest that sea level rose at a rate of about one to two centimeters per century (0.4 to 0.8 inch) over the past 3,000 years. Some studies have interpreted direct sea-level measurements made throughout the 20th century to show that the level is now rising at a much faster rate, about 10 to 25 centimeters per century (4 to 10 inches), but other studies conclude that the rate is much lower than that. To whatever extent sea-level rise may have accelerated, the change is thought to have taken place before the period of industrialization.

Before considering whether the ongoing sea-level rise has anything to do with human use of fossil fuels, let’s examine what science has to say about how global temperature change may relate to sea-level change. The matter is more complicated than it first appears. Water expands as it warms, which would contribute to rising sea level. But warming increases the evaporation of ocean water, which could increase the snowfall on the Arctic and Antarctic ice sheets, remove water from the ocean, and lower sea level. The relative importance of these two factors is not known.

We do know from studies of the West Antarctic Ice Sheet that it has been melting continuously since the last great ice age, about 20,000 years ago, and that sea level has been rising ever since. Continued melting of the ice sheet until the next ice age may be inevitable, in which case sea level would rise by 15 to 18 feet when the sheet was completely melted. Other mechanisms have been suggested for natural sea-level rise, including tectonic changes in the shape of the ocean basins. The theoretical computer climate models attribute most of the sea-level rise to thermal expansion of the oceans, and thus they predict that further global temperature increase (presumably from human activities) will accelerate the sea-level rise. But because these models cannot deal adequately with the totality of the natural phenomena involved, their predictions about sea-level rise should be viewed skeptically.

The natural causes of sea-level rise are part of Earth’s evolution. They have nothing to do with human activities, and there’s nothing that humans can do about them. Civilization has always adjusted to such changes, just as it has adjusted to earthquakes and other natural phenomena. This is not to say that adjusting to natural changes is not sometimes painful, but if there’s nothing we can do about certain natural phenomena, we do adjust to them, however painfully. Sea-level rise is, most likely, one of those phenomena over which humans have no control.

Some environmentalists claim that weather-related natural disasters have been increasing in frequency and severity, presumably as a result of human-caused global warming, but the record does not support their claims. On the contrary, several recent statistical studies have found that natural disasters—hurricanes, typhoons, tropical storms, floods, blizzards, wildfires, heat waves, and earthquakes—are not on the increase. The costs of losses from natural disasters are indeed rising, to the dismay of insurance companies and government emergency agencies, but that’s because people in affluent societies construct expensive properties in places vulnerable to natural hazards, such as coastlines, steep hills, and forested areas.

Because society has choices, we must ask what the likely effects would be, on the one hand, if people decided to adjust to climate change, regardless of its causes, and, on the other, if governments implemented drastic policies to attempt to lessen the presumed human contribution to the change. From an economic perspective at least, adjusting to the change would almost surely come out ahead. Several analyses have projected that the overall cost of the worst-case consequences of warming would be no more than about a two percent reduction in world output. Given that average per capita income will probably quadruple during the next century, the potential loss seems small indeed. A recent economic study emphasizing adaptation to climate change indicates that in the market economy of the United States the overall impacts of modest global warming are even likely to be beneficial rather than damaging, though the amount of net benefit would be small, about 0.2 percent of the economy. (We need always to keep in mind the statistical uncertainties inherent in such analyses; there are small probabilities that the benefits or costs could turn out to be much greater than or much less than the most probable outcomes.)

In contrast, the economic costs of governmental actions restricting the use of fossil fuels could be large indeed, as suggested by the Nordhaus study cited earlier on the costs of compliance with the Kyoto treaty. One U.S. government study proposed that a cost-effective way of bringing about fossil fuel reductions would be a combination of carbon taxes and international trading in emissions rights. Emissions rights trading was, in fact, included in the modified Kyoto agreement. But such a trading scheme would result in huge income transfers, as rich nations paid poor nations for emissions quotas that the latter would probably not have used anyway—and it’s not reasonable to assume that rich nations would be willing to do this.

Taking into account the large uncertainties in estimating the future growth of the world economy, and the corresponding growth in fossil fuel use, one group of economists puts the costs of greenhouse gas reduction in the neighborhood of one percent of world output, while another group puts it at around five percent of output. The costs would be considerably higher if large reductions were forced upon the global economy over a short time period, or if, as is likely, the most economically efficient schemes to bring about the reductions were not actually employed. Political economists Henry Jacoby, Ronald Prinn, and Richard Schmalensee put the matter bluntly: “It will be nearly impossible to slow climate warming appreciably without condemning much of the world to poverty, unless energy sources that emit little or no carbon dioxide become competitive with conventional fossil fuels.”

Some global warming has been under way for more than a century, at least partly from natural causes, and the world has been adjusting to it as it did to earlier climate changes. If human activity is finally judged to be adding to the natural warming, the amount of the addition is probably small, and society can adjust to that as well, at relatively low cost or even net benefit. But the industrial nations are not likely to carry out inefficient, Kyoto-type mandated reductions in fossil fuel use on the basis of so incomplete a scientific foundation as currently exists. The costs of so doing could well exceed the potential benefits. Far more effective would be policies and actions by the industrial countries to accelerate the development, in the near term, of technologies that utilize fossil fuels (and all resources) more efficiently and, in the longer term, of technologies that do not require the use of fossil fuels.

If climate science is to have any credibility in the future, its pursuit must be kept separate from global politics. The affluent nations should support research programs that improve the theoretical understanding of climate change, build an empirical database about factors that influence long-term climate change, and increase our understanding of short-term weather dynamics. Such research is fundamental to the greenhouse gas issue. But its rewards may be greater still, for it will also improve our ability to cope with extreme weather events such as hurricanes, tornadoes, and floods, whatever their causes.

Jack M. Hollander is professor emeritus of energy and resources at the University of California, Berkeley. His many books include The Energy-Environment Connection (1992) and The Real Environmental Crisis: Why Poverty, Not Affluence, Is the World’s Number One Enemy (2003), published by the University of California Press, from which this essay has been adapted. Copyright © 2003 by the Regents of the University of California.

The biggest remaining problem is quantifying the effects of variable cloud cover

Clouds have a hundred times stronger effect on weather and climate than carbon dioxide in the atmosphere. Even if the atmosphere’s CO2 content doubled, its effect would be cancelled out if the cloud cover expanded by 1%, as shown by H. E. Landsberg: Man-made climatic changes. In: Proceedings of the symposium on physical and dynamic climatology of the World Meteorological Organization 347 (1974), 262.

and how cloud cover responds to an increase in global temperature.

We know quite well how cloud cover relates to cosmic flux:

Cosmic ray flux modulated by solar activity, from Svensmark & Friis-Christensen:

The thin curve in Figure 6 presents the monthly mean counting rates of neutrons measured by the ground-based monitor in Climax, Colorado (right scale). This is an indirect measure of the strength of galactic and solar cosmic rays. The thick curve plots the 12-month running average of the global cloud cover expressed as change in percent (left scale). It is based on homogeneous observations made by geostationary satellites over the oceans. The two curves show a close correlation. The correlation coefficient is
r = 0.95.

Not much residual left for Temperature effect is there?

Though you are welcome to use the Climate Data Library to figure out the residual correlation of global temp vs global cloud coverage for us:

http://ingrid.ldeo.columbia.edu/index.html

(It's somewhat amusing to me that many of your references and supporting arguments come from the CO2science Web site. They are presenting their skeptical case, and it's obviously a one-sided presentation. When one investigates what other data and information can be assessed, it is clear that the CO2science Web site is excluding quite a bit.)

I use them among other's in my searches via GOOGLE, for good and sufficient reason. The lessthan-skeptic sources have a clear UN global political agenda to grind of their own. That is why sites like CO2science and Daley's exist, to present the counter views demonstrating the weaknesses and failures of global warming models of the UN/IPCC.

The Politician's use of global warming, Tim Wirth (1990):

"We've got to ride the global warming issue. Even if the theory of global warming is wrong, we will be doing the right thing - in terms of economic policy and environmental policy."
as quoted in NCPA Brief 213; September 6, 1996

and Steven Schneider, a climatologist at Stanford and the National Center for Atmospheric Research (NCAR) in Boulder, Colorado:

"On the one hand, as scientists we are ethically bound to the scientific method, in effect promising to tell the truth, the whole truth, and nothing but - which means that we must include all the doubts, the caveats, the ifs, ands, and buts. On the other hand, we are not just scientists but human beings as well. And like most people we'd like to see the world a better place, which in this context translates into our working to reduce the risk of potentially disastrous climatic change. To do that we need to get some broadbased support, to capture the public's imagination. That, of course, entails getting loads of media coverage. So we have to offer up scary scenarios, make simplified, dramatic statements, and make little mention of any doubts we might have. This 'double ethical bind' we frequently find ourselves in cannot be solved by any formula. Each of us has to decide what the right balance is between being effective and being honest. I hope that means being both." (Quoted in Discover, pp. 45-48, Oct. 1989, see also American Physical Society, APS News August/September 1996).

Make very clear the stance of those supporting the anthropogenic source theories of the global warming community and why they are willing to hold up their flawed analysis as if it were a scientific "fact".

Obviously I don't have time to reply to everything until next week, but I wonder where Hoyt gets his information. By the way, I don't think that page has changed since 1997.

3) The models predict that cloud cover should be decreasing, and, in fact, such a decrease is crucial to amplify the greenhouse effect so it becomes the "enhanced" greenhouse effect. All measurements show cloud cover is increasing. ***

I did a quick Web search.

From What happens if we double CO2 in a climate model? (from the United Nations Framework Convention on Climate Change site)

"In most models cloud cover increases in a warmer climate. This affects the energy budget in two opposing ways. Clouds reflect sunlight, reducing the amount of energy reaching the surface. They also act as a "blanket", reducing the earth's energy losses to space. As the total cloud cover increases, the first effect acts to reduce the warming (a negative feedback) while the second effect acts to increase it (positive feedback). Clouds are a major source of uncertainty. If clouds are allowed to change (and changes in sea-ice are suppressed), different climate models give answers ranging from 1.5 to 4.5 C for the warming due to doubling CO2. If the effects of cloud feedbacks are eliminated, this range is reduced to 1.7-2.3 C."

It's old (dated 1993). Did the models change that much in four years that "most" of them predict the opposite of what they predicted in 1993? That's hard for me to believe.

Look at figure 1 in this PDF paper:

Cloud representation in climate models:

It shows 10 models responding to a doubling of CO2. Five models show a decrease in top-of-the-atmosphere cloud radiative forcing, five show an increase. (The increases predicted are greater than the decreases, in general.) I'm not sure how increase or decrease in radiative forcing translates to increase or decrease in actual cloud cover, but clearly there's no majority agreement in the models!

So this quick survey indicates to me that point 3 is questionable. If you can find some additional support for the statement of that point, feel free. But as it stands it doesn't appear to reflect the state-of-the-science.

More next week.

So this quick survey indicates to me that point 3 is questionable. If you can find some additional support for the statement of that point, feel free. But as it stands it doesn't appear to reflect the state-of-the-science.

As far as I can determine, the Holtz statement may have been rooted in a limited set of models as his chart of scoring results, refers to cloud cover being inconsistent among the models instead of generally one direction.

I'll go with Richard S. Lindzen's overall assessment(2000) of the GCM's as more representative the the current-state-of-the-science.
From Bulletin of the American Meteorological Society (March 2000) &
an interview with Tech Central Station (March 5, 2001, www.techcentralstation.com),

1) Water Vapor Feedback
The biggest uncertainty in climate science is how feedbacks affect the climate. Global warming theory posits that a rise in atmospheric CO2 will only cause a slight warming of the atmosphere, on the order of about 1 degree centigrade. This small amount of warming, according to standard global warming theory, speeds up evaporation, increasing the amount of water vapor, the main greenhouse gas in the atmosphere. This positive feedback is where most of the predicted warming comes from.
A new study in the Bulletin of the American Meteorological Society (March 2000) shows that the reverse is true. The authors find a negative water vapor feedback effect that is powerful enough to offset all other positive feedbacks. Using detailed daily observations of cloud cover from satellites in the tropics and comparing them to sea surface temperatures, the researchers found that there is an "iris effect" in which higher temperatures reduce the warming effect of clouds.
According to a NASA press release about the study, "Clouds play a critical and complicated role in regulating the temperature of the Earth. Thick, bright, watery clouds like cumulus shield the atmosphere from incoming solar radiation by reflecting much of it back into space. Thin, icy cirrus clouds are poor sunshields but very efficient insulators that trap energy rising from the Earth’s warmed surface. A decrease in cirrus cloud area would have a cooling effect by allowing more heat energy, or infrared radiation, to leave the planet."
The researchers found that a one degree centigrade rise in ocean surface temperature decreased the ratio of cirrus cloud area to cumulus cloud area by 17 to 27 percent, allowing more heat to escape.
In an interview with Tech Central Station (March 5, 2001, www.techcentralstation.com), Dr. Richard S. Lindzen, the lead author, said that the climate models used in the IPCC have the cloud physics wrong. "We found that there were terrible errors about clouds in all the models, and that that will make it impossible to predict the climate sensitivity because the sensitivity of the models depends primarily on water vapor and clouds. Moreover, if clouds are wrong, there’s no way you can get water vapor right. They’re both intimately tied to each other." Lindzen argues that due to this new finding he doesn’t expect "much more than a degree warming and probably a lot less by 2100."

Yet another problem with the UN/IPCC global warming models:

Climate Models Fail to Reproduce Natural Temperature Fluctuations

Climate models that serve as the basis for global warming predictions fail to reproduce correctly the fluctuations in atmospheric temperatures over time scales of months and years, according to new research appearing in the July 8 [2002] issue of Physical Review Letters.
The study explains that large-scale atmospheric and oceanic dynamics are solved in the models using highly sophisticated numerical solutions, but that there are also "subgrid-scale processes" that are too small to be modeled. These are handled by "parameterization schemes," which amounts to little more than arbitrarily assigning a value to the particular process being considered. Some of these subgrid-scales includes, surprisingly enough, the roles of various greenhouse gases including carbon dioxide and the effect of aerosols.
In earlier research, the authors discovered a universal mathematical relationship, known as a scaling law, which describes the correlations between temperature fluctuations. What they found was that temperature variations from their average values exhibit persistence that decays at a well-defined rate. "The range of this persistence law exceeds ten years, and there is no evidence for a breakdown of the law at even larger timescales," according to the study.
Using this scaling law, the researchers tested seven general circulation models, including the U.S.-based model at the National Climate for Atmospheric Research, against historical atmospheric temperature data from six representative sites. What they found was that the models, "fail to reproduce the universal scaling behavior observed in the real temperature records."
The researchers explain that, "It is possible that the lack of long-term persistence is due to the fact that certain forcings such as volcanic eruptions or solar fluctuations have not been incorporated in the models." But they cannot "rule out that systematic model deficiencies (such as the use of equivalent CO₂ forcing to account for all other greenhouse gases or inaccurate spatial and temporal distributions of sulfate aerosols) prevent the [climate models] from correctly simulating the natural variability of the atmosphere."
They conclude, "Since the models underestimate the long-range persistence of the atmosphere and overestimate the trends, our analysis suggests that the anticipated global warming is also overestimated by the models."

You left out: sulphate aerosols and black-soot aerosols.

Correct, as the modeled magnitude of sulphate aerosols are not supported in actual atmospheric mearsurements & black-soot aerosols effects tend to cancel out the model sulphate aerosol effects.

Sulphate aerosols were added to erroneous models to adjust their output to force fit them to historical temperature data but have failed in verification in regards to physical measurements on the atmosphere.

Global Warming Score Card

5) The models attribute the cooling from about 1940 to 1970 to sulfate aerosols. The quantity of aerosols they used are not based upon measurements, but are themselves model results. One prediction of this model is a maximum amount of aerosols in central Europe. Observations of atmospheric transmission in Davos Switzerland, right in the middle of the region where the model maximum in sulfates presumably existed, show no change in atmospheric transmission, contrary to the IPCC predictions. Observations in Belgium, Ireland, and other locations also falsify the IPCC modeled amounts of sulfate aerosols.
6) The models predict sulfate aerosols will cause a cooling forcing of 0.6 to 0.9 W/m². Actual field measurements of the scattering properties of sulfate aerosols show that the models overestimate their cooling potential by a factor of 3 to 5. These measurements falsify the model's radiative treatment of sulfates and show that the cooling from 1940 to 1970 cannot be attributed to anthropogenic aerosols.
7) The models neglect to include soot particles, which warm. Measurements show that the warming by soot offsets any cooling by sulfates, particularly in urban regions.

From What happens if we double CO2 in a climate model? (from the United Nations Framework Convention on Climate Change site)

And what does doubling have to due with any reasonable for the future?

http://www.pacificresearch.org/pub/cap/2003/cap_03-02-20.html

"The Economist, which provides the best environmental reporting of any major news source, carried a small story last week about a simple methodological error in the latest U.N. global warming report that has huge implications. The article, "Hot Potato: The Intergovernmental Panel on Climate Change (IPCC) Had Better Check Its Calculations" (February 15 print edition), reviews the work of two Australian statisticians who note an anomaly in the way the IPCC estimated world carbon dioxide emissions for the 21st century."
......
"The IPCC's method has the effect of vastly overestimating future economic growth (and, therefore, CO2 emissions) by developing nations. The fine print of the IPCC's projections, for example, calls for the real per-capita incomes of Argentina, South Africa, Algeria, Turkey, and even North Korea to surpass real per-capita income in the United States by the end of the century. Algeria? North Korea? The IPCC must be inhaling its own emissions to believe this."

& Hot Potato Revisited:
A lack-of-progress report on the Intergovernmental Panel on Climate Change

As well as the fact that doubling CO₂ concentration simply does not lead to the results that the demonstrably flawed UN/IPCC models(Global Warming Score Card) would have us believe:

Re-cycling of Infra-Red Energy

According to Dr Hugh Ellsaesser's IPCC submission, "The direct increase in radiative heating of the lower atmosphere (tropopause level) due to doubling CO2 is 4 wm^-2. At the surface it is 0.5 - 1.5 wm^-2". Schlesinger & Mitchell (1985), estimated this surface flux at 2 wm^-2. Thus, depending on the model, or modeler, the estimates for increased surface flux following a CO2 doubling, varies between +0.5 and +2 wm^-2. An above-averaged figure of +1.5 wm^-2will be assumed here for purposes of analysis and comparison.

At the current surface temperature (288^oK) Doubling the atmospheric CO2 concentration from 340ppmv can only add 1.5w/m² at the surface for a total surface radiative forcing of

390.08+1.5 = 391.58w/m²

providing a

(391.58/5.67*10^-8)^0.25-288^oK = 0.277^oK (C)increase in surface temperature for doubling of atmospheric CO₂ concentration.

A result well within any reasonable expectation of our rough estimate of 0.27oC associated with CO₂ doubling demonstrated in the paleo CO₂-temperature record of my prior replies.

It'd be nice if Lindzen was right, but Lindzen isn't necessarily right.

Does the Earth Have an Iris Analog?

Evidence Against the Iris Hypothesis

"Lin's team took the measurements made every day by CERES over the tropical oceans and plugged them into the same model that Lindzen used. Instead of the strong negative feedback that Lindzen's team found, Lin's team found a weak positive feedback (Lin et al. 2001). That is, Lin found that clouds in the tropics do change in response to warmer sea surface temperatures, but that the cloud changes serve to slightly enhance warming at the surface. Specifically, whereas Lindzen's experiment predicts that cirrus clouds change in extent to reduce warming at the surface by anywhere from 0.45 to 1.1 degrees, Lin's experiment predicts that changes in the tropical clouds will help warm the surface by anywhere from 0.05 to 0.1 degree (Lin et al. 2001)."

Reconciling the Differences (journal references are in this section)

Lindzen's a good scientist, and one of the best global warming skeptics currently active. Just because he's good doesn't mean that he's right all the time.

But you won't get much of an argument from me that the cloud feedback is still one of the great uncertainties in predictive climate modeling. I just wish that occasionally you'd acknowledge that the arguments from the skeptical side (such as Hoyt's scorecard assessments) won't always be right, too.

More today as time allows. I think that you've provided me with eight posts that I could respond to.

It'd be nice if Lindzen was right, but Lindzen isn't necessarily right.

Nor Lin, nor the UN/IPCC.

Reconciling the Differences

Currently, both Lindzen and Lin stand by their findings and there is ongoing debate between the two teams. At present, the Iris Hypothesis remains an intriguing hypothesis—neither proven nor disproven. The challenge facing scientists is to more closely examine the assumptions that both teams made about tropical clouds in conducting their research because therein lies the uncertainty.
***
Historically, it has been very difficult for scientists to measure clouds’ properties in multi-layer cloud formations using passive remote sensors. In 2004, scientists grappling with this problem will gain one of the most powerful tools ever developed for studying multi-layer cloud properties on a global scale.

We learn as we go forward, but to assume that the GCM's are the last word in climate theory & assessment of "global warming" as predominately manmade, as the UN/IPCC would have us believe, is a far cry from the actual state of atmospheric science.

I just wish that occasionally you'd acknowledge that the arguments from the skeptical side (such as Hoyt's scorecard assessments) won't always be right, too.

Lindzens argument is not from Hoyt's sight :) However I do not rely on single source or studies in anycase. The overall picture is what I go for, and to demonstrate the inadequacies of relying on the UN/IPCC models for anything relating to the climate for the next day much less the next century. The point is that reliance on very sketchy and poorly understood science for economic and political policy decisions is a disaster in the making much greater on mankind, than any hypothetical effect that mankind might have on global climate.

Once again we must go back to the UN/IPCC GCM theory about which we argue:

1) Water Vapor Feedback

"The biggest uncertainty in climate science is how feedbacks affect the climate. Global warming theory posits that a rise in atmospheric CO2 will only cause a slight warming of the atmosphere, on the order of about 1 degree centigrade. This small amount of warming, according to standard global warming theory, speeds up evaporation, increasing the amount of water vapor, the main greenhouse gas in the atmosphere. This positive feedback is where most of the predicted warming comes from.

Lindzen claims that one problem with the UN/IPCC modeling is that warming feedback from the surface is much less due, at least in part, one theory is the so-called "iris effect" of changing cirrus cloud cover in response to surface heating.

Lin demonstrates the potential of only a minimal warming arising from changing cloud cover from surface feedbacks in CO₂ driven models. The Lin results demostrate increases in high cirrus clouds arising from changes in surface temperature, at the least, compensate for increases in lower level clouds arising from that same feedback.

Lindzen demonstrates the potential for an actual cooling sufficient to negate the UN IPCC climate feedbacks.

Above all we need to remember:

Clouds have a hundred times stronger effect on weather and climate than carbon dioxide in the atmosphere. Even if the atmosphere’s CO2 content doubled, its effect would be cancelled out if the cloud cover expanded by 1%, as shown by H. E. Landsberg: Man-made climatic changes.
In: Proceedings of the symposium on physical and dynamic climatology of the World Meteorological Organization 347 (1974), 262.

Which establishes the effect on surface temperature, that independant variation of the cloud cover has when it is a consequence of variation in solar wind or other external factors as opposed to warming feedback from the surface.

Solar activity impacts surface temperature in at least 3 ways,

1) heating from direct solar irradiation of the surface.
2)solar warming increases the water vapor content of the atmospere(acting as a primary GHG) thus increasing back irradiation of the greenhouse effect from the water vapor dominated environment.
2) changing cloud cover induced by modulation of cosmic ray flux(independant of surface temperature feedbacks) through the Svensmark effect, refer to post #121 above

That is why we see such a strong correlation between solar activity (solar wind & solar irradiation) and surface temperature: A linear regession of solar activity alone (direct irradiation and the solar wind effect on cloud cover through modulation of gamma radiation flux) accounts for nearly the total change in temperature across the last 250yrs encompassing the industrial age.

Top of Atmosphere Solar Irradiation left(dottedline),
Relative Temperature (solidline, 1750 base) right scale.
Hoyt and Schatten 1997

Let's look at Hoyt and Schatten. While I credit the output of your calculations, I can't say the same for the input:
***
So Hoyt and Schatten's reconstruction shows a maximum range of variability of about 4 W m-2 TSI in the 20th century, while three other groups show a maximum range of variability of about 2 W m-2.
***
Now I will ask you: what happens if you amend your calculations with only a 2 W m-2 change in solar variability, rather than 4?

A closer look as regards halving the variation of solar activity, From the source of your graphic(Figure 6.5 ) on Solar forcings: http://www.grida.no/climate/ipcc_tar/wg1/245.htm

The estimate for solar radiative forcing since 1750 of 0.3 Wm^-2, shown in Figure 6.6, is based on the values in Figure 6.5 (taking the 11-year cycle minimum values in 1744 and 1996). Clearly the starting date of 1750 (chosen for the date of the pre-industrial atmosphere in Figure 6.6) is crucial here: a choice of 1700 would give values about twice as large; a choice of 1776 would give smaller values (particularly using the Hoyt and Schatten series). The range of 0.1 to 0.5 Wm^-2 given in Figure 6.6 is based on the variability of the series, the differences between the reconstructions and uncertainties concerning stratospheric adjustment (see Section 6.11.2.1). However, because of the large uncertainty in the absolute value of TSI and the reconstruction methods our assessment of the “level of scientific understanding” is “very low”.

This statement was cause for me to go back and look closer at the graphic and look at the change (as opposed to the absolute level) in each series more carefully.

Please note from the graphic that the deviation from 1700 to 1997, is approximately 4wm^-2 TOA for both Lean and the Hoyt-Schatten[H-S] series. Differences lay in detail timing in accord to the actual proxies used in specific series but not exceptionally so in overall peak-peak range (at least not to the degree you would have us accept (half of the Hoyt-Schatten deviation).

Additionally the Lean series appears to reasonably agree with the H-S series across the 1800-1998 pk-pk range I selected for peak-peak analysis.

Lean = approx. 3.5wm^-2 TOA_(pk-pk) while
Hoyt-Schatten varies 4.3wm^-2 TOA_(pk-pk) of the analysis in reply #105.

To halve the the Solar forcing merely on the basis of statement of solar variability being 2wm^-2 is unacceptable even by the Lean series.

I will agree with taking a mean of the variations between Lean and Hoyt-Schatten of 3.9wm^-2 TOA_(pk-pk) as being approximately representative for the 1800-1997 time frame of the calculation.

That would reduce the original 0.85^oC calculation of solar activity contribution to about 0.76^oC of the 1800-1997 industrial era variation in temperature, accounted for by Solar activity. A value substantially greater(nearly double) that assigned by you.

Starting from the top (to the extent that is feasible):

I'm not going to respond to all of the points on the "global warming scorecard". That would be fruitless and branch the discussion too much. If you want, we can return to that down the line and examine them one at a time. I responded on the cloud cover one since you had isolated it.

So we'll start with a response to the first of many. I'll try and do one or two a day.

After noting a difference in solar activity plots, I asked if there was now "room" for GHG influence on warming, as suggested by other researchers. You replied:

No because a linear regession of solar activity alone (direct irradiation and the solar wind effect on cloud cover through modulation of gamma radiation flux) accounts for the total change in temperature.

This pushes the gamma-ray influence on cloud cover. Let's see what can be said about that.

Solar Activity, Cosmic Rays, Clouds and Climate - An Update

Final sentence of abstract:

"In either case we note that since proxiesfor solar variability show no general trend over the last 50 years thereis no indication for a trend in (indirect) solar forcing in this period."

Another take on that paper:

Study: Radiation changes do not explain global warming

Quoting: "“We cannot find any clear correlation between cloud cover and cosmic rays,” says meteorologist Jón Egill Kristjánsson at the University of Oslo. Svensmark’s hypothesis rests largely on precisely this relationship. But the data cover only one-and-a-half solar cycles, so it is still impossible to draw certain conclusions, Kristjánsson points out. He is an expert on the role of clouds in the climate system."

"Although the new analyses weaken Svensmark’s hypothesis, they do show a clear relationship between cloud cover and the amount of energy the earth receives from the sun. The result is interesting because it suggests a mechanism for how the sun can contribute to natural climate variation.

“Solar radiation peaks about every eleven years,” says Kristjánsson. “We believe that this leads to, among other things, slightly higher ocean temperatures, which results in fewer of the low clouds that have particular significance for the climate.”

But before you get too excited about that:

"Solar radiation has not become more intense over the last 40–50 years,” explains Kristjánsson. “Thus the relationship between solar radiation and cloud cover cannot explain the warming observed on the earth’s surface during this period.”

Indicating that there really isn't any evidence for a gamma-ray or cosmic-ray influence on cloud cover and climate over the past 50 years. And indicating that while solar irradiance variability can influence climate via cloud cover changes, since there hasn't been a particular trend in solar irradiance over the past 50 years, there hasn't been an apparent trend in cloud cover changes forced by that mechanism, either.

Using this forcing and the GCM postulated feedbacks giving rise to climate sensitivity of 0.75 C/wm-2, we should expect to see a 0.28 C p-p variation in global tropospheric temperatures with an 11 year solar cycle period. Observations indicate that the temperature oscillation is less than 0.05 C and it is difficult to detect.

First, does "p-p" mean "peak-to-peak"?

Second, climate sensitivity is cumulative. That value is partly due to changes in ice sheet and glacier extent, and you can't possibly expect that that will respond in 11 years. Ocean heat storage is also part of it. So I don't think the comparative methodology of trying to determine the effect of the 11-year solar cycle variability on temperatures over that same period is valid. Time-scales do matter.

Finally, you say:

Seems to me even you admit there there is room for substantial doubt as to the magnitude or even sign of any effect "human created" CO2, Methane etc. may have on our Climate future.

Substantial doubt -- no. Uncertainty, yes. But there is also certainty in some quarters. The view that CO2 will matter not at all, or just a little, is on the periphery of the discussion, which is why I am discussing it with you. I invite you to see what Richard Lindzen has predicted; I'll show you what Pat Michaels has predicted:

Michaels: Global climate will not change markedly

----Two years ago the IPCC produced its third assessment report, which indicated a global rise in temperatures of 1.4 to 5.8 degrees Celsius for 1990 to 2100. Michaels’ new independent study indicates the most likely value is around 1.6 degrees Celsius, near the low end of the IPCC range. He used an assortment of data to produce a range of possible temperatures for the period, and all were substantially less broad than the IPCC’s range.
----- In one scenario, he used data from recent studies that closely examine the assumptions made about climate behavior in the U.N. report and found a range of warming of 1.1 to 2.8 degrees Celsius.
----- When using data of actual climate change rates during the past 25 years of greenhouse warming, and projecting it out to the year 2100, he found a range of 1.5 to 2.6 degrees Celsius.
----- “Almost all models produce a constant rate of warming,” Michaels said. “So why not let nature choose that rate?”
----- When he factored both aspects of his study together, he found a range of 1.0-1.6 degrees Celsius.
----- Additionally, by adjusting the averages of a range of climate models to reflect actual observed changes in temperature in nature, he found a warming range of 1.3-3.0 degrees Celsius, with a central value of 1.9 degrees Celsius."

I tend to agree. I think the warming in the next century will be 1.5-2.5 C. Michaels and Hansen converge in this range. For that reason, I advocate Hansen's alternative scenario, which encourages control of black soot aerosols along with CO2 emissions (to some extent) in developing nations, along with associated public health benefits. He also advocates fairly aggressive implementation of new technology, leading to reduced energy use (things like wider use of compact fluorescent lighting, co-generation, biomass generation). In addition to that, I advocate more use of clean and safe nuclear energy (I'm obviously not German). CO2 sequestration may also be viable. In essence, I know that the Kyoto Protocol is useless and indefensible (and you can research my numerous FR statements to that effect). But there are two reasons to pursue technology that will reduce fossil-fuel energy dependence: national economic security and climate change.

I probably can't provide another response today; I accidentally delete half of this when I was almost done and had to retype it. We have plenty of time.

"Solar radiation has not become more intense over the last 40–50 years,” explains Kristjánsson. “Thus the relationship between solar radiation and cloud cover cannot explain the warming observed on the earth’s surface during this period.”

Hmm last 40-50 years? While the statement of Solar Radiation not becoming more intense over the last 40-50 years, is technically correct for that time period, the relationship between Solar Activity and Temperature remained highly correlated throughout.

At no point is a constant rise in solar intensity required, it is the fact that change in solar activity and temperature deviation is so closely correlated that makes the case for the dominance of Solar Activity on change in climate.

I bring your attention to Hoyt Schratten results for 1947-1997, for the period that Kristjánsson states "Solar radiation has not become more intense over the last 40–50 years,”

Top of Atmosphere Solar Irradiation left(dottedline),
Relative Temperature (solidline, 1750 base) right scale.
Hoyt and Schatten 1997

Overall there is minimal rise in Solar radiation intensity, but Solar Activity series of Hoyt is generally correlated with the actual change in global surface tempertures. Looking at the two centuries leading into the period, we see a full range of solar activity and temperature that clearly demonstrates the overall correlation very well.

The remarks you have focused on is a prime example of what I see as the double speak of the "Global Warming" appologists. Taking statements of selective short term conditions to generalize into a conclusion that is contrary to the whole picture.

If you insist on using such blatent misstatement of the issues here, I see no point in continuing.

The Hoyt-Schatten Solar Activity series was specifically constructed from solar measurements to provide a predictive model of global surface temperature based in solar factors alone. In that they appear to be exceptionally successful as is demonstrated in the 250yr graphic above.

Statements such as:

"In either case we note that sinceproxies for solar variability show no general trend over the last 50 years thereis no indication for a trend in (indirect) solar forcing in this period."

and

"Solar radiation has not become more intense over the last 40–50 years,” explains Kristjánsson. “Thus the relationship between solar radiation and cloud cover cannot explain the warming observed on the earth’s surface during this period.”

Simply do not create a serious rebuttal to the Hoyt-Schatten evidence nor provide evidence of a better or even equal CO2 correlation to variation in Global temperatures than that which is demonstrable in a Solar Activity series.

I'm sorry, but I simply do not buy the hype that you are tossing out here.

Is the same correlation evident for Lean et al. 1995, Solanki and Fligge 1998, and Lockwood and Stamper, 1999? Why the reliance on Hoyt and Schatten's data exclusively?

Incorrect. We have a warming trend, strong over the past 25-30 years. If there is no trend in solar activity, and no trend in forcing by an increase or decrease in solar activity, then the observed warming in this time period is being caused by something else. You aren't advocating a mechanism with a significant lag time, whereas I am.

Hoyt and Schatten's results are double what the other cited datasets indicate. Perhaps Kristjansson doesn't think that the cumulative data analysis shows a marked increase in solar intensity. Given your position, I can see why you would.

Yes, and the previous material I provided indicated that no one is disputing a solar contribution over the past 150 years. The dispute is over what is causing the temperature rise NOW.

The same general patterns are seen in the Lean et al. data, except that the change is less marked, and there is less of a defined trend from 1975 onward.

What are we seeing here? Scientific disputes about what is occurring, what is driving the system, what the data is, what the data indicates. Every time you post something that you take to be definitive, I have little difficulty finding an alternative view that is not nearly as definitive. You seem to think that the solar activity connection with temperature change is settled. News: it's not.

Oh yeah: correlation is not causation. Many scientists have gone down that road and been misled.

I didn't expect that I'd have time for this, but that's all I have time for now. I'll try to reply to another of your messages tomorrow. Even if you stop responding, I have a backlog to address.

First, does "p-p" mean "peak-to-peak"?

yes

Second, climate sensitivity is cumulative. That value is partly due to changes in ice sheet and glacier extent, and you can't possibly expect that that will respond in 11 years. Ocean heat storage is also part of it. So I don't think the comparative methodology of trying to determine the effect of the 11-year solar cycle variability on temperatures over that same period is valid. Time-scales do matter.

As is shown in my calculation, the variation for the 11 year cycle should have been on the order of .24^oC for a 0.75wm^-2 Climate sensitivity. The damping is too great for it to be readily visible which is why it is on the order of 0.05^oC. That is why it is necessary to look at decadal and centenial variations constructed in the Hoyt Schatten solar activity series, which does provided a strong and decisive predictor of Global Surface temperature variations throughout the 250 year range of the series.

It is the Hoyt Schatten series that I used for validation with your 0.75wm^-2 Climate sensitivity number.

Using your 0.75wm^-2 Climate sensitivity number, the peak-peak range of the Hoyt-Schatten Solar Activity series fits the peak to peak global surface temperature range throughout the 250 year period as well as maintain a visible, highly correlated, aspect with surface temperatures throught the entire period of the graphic.

That to me is a very strong confirmation of the hypothesis that Solar Activity is the primary driver of Global temperature changes over periods on the order of centuries as well as generational/decadal variations.

The CO2 concentration data series does not show anything near the correlation to actual surface temperature changes through the same period. In point of fact the correlation for global surface temperature and CO2 across the same period is very low, especially if the Hoyt Shratten correlation is subtracted from the temperature series and we run the CO2 concentration series against the surface temperature residuals.

Seems to me even you admit there there is room for substantial doubt as to the magnitude or even sign of any effect "human created" CO2, Methane etc. may have on our Climate future.
Substantial doubt -- no. Uncertainty, yes. But there is also certainty in some quarters. The view that CO2 will matter not at all, or just a little, is on the periphery of the discussion, which is why I am discussing it with you.

Good of you,.

I invite you to see what Richard Lindzen has predicted;

1) Water Vapor Feedback

Lindzen argues that due to this new finding he doesn’t expect "much more than a degree warming and probably a lot less by 2100."

I'll show you what Pat Michaels has predicted:

"Michaels’ new independent study indicates the most likely value is around 1.6 degrees Celsius, near the low end of the IPCC range."

I note the sides are converging in the range to expect temperatures to rise across this century. It is well to note the Tropospheric trend of 0.074^oC/decade projects a 0.74^oC or less century target, assuming no change in magintudes and acceleration of the actual drivers effecting global temperatures.

However the issue is not whether there will be some increase in global surface temperatures, the issue is about what are the primary drivers and causitive factors.

I see solar activity, interplanetary, and interstellar effects driving watervapor/clouds as the primary driver of global temperature changes,

You & the IPCC folks look at for a anthropogenic causes on the "hope" man can somehow slow or control the global temperature change or in a blacker agenda implement political/social changes on the pretext of global environmental crisis.

I believe that efforts would be better spent in adaption to actual physical change as opposed to massive intervention in global economy and politics to effect what I and others see as only marginal effect on global temperatures.

" There is no dispute at all about the fact that even if punctiliously observed, (the Kyoto Protocol) would have an imperceptible effect on future temperatures -- one-twentieth of a degree by 2050. "

Dr. S. Fred Singer, atmospheric physicist
Professor Emeritus of Environmental Sciences at the University of Virginia,
and former director of the US Weather Satellite Service;
in a Sept. 10, 2001 Letter to Editor, Wall Street Journal

I think the warming in the next century will be 1.5-2.5 C. Michaels and Hansen converge in this range.

I advocate Hansen's alternative scenario, which encourages control of black soot aerosols along with CO2 emissions (to some extent) in developing nations, along with associated public health benefits.

All of which imply a degree of governmental control over global politics & economies that cause me a great deal of concern.

He also advocates fairly aggressive implementation of new technology, leading to reduced energy use (things like wider use of compact fluorescent lighting, co-generation, biomass generation).

As long as it fits into an unfettered market principles it works for me, compact flourescent lighting makes prefect sense, costs less and and conserves energy as well as my pocketbook. Biomass generation, that can be accomplished with expanding agriculture(ocean as well as land.) I don't see any impediments there and makes economics sense outside of any "global crisis". Other related solutions that make economic sense and pay their own way will develop quite naturally.

I advocate more use of clean and safe nuclear energy (I'm obviously not German).

Go for it, that doesn't need a global climate crisis for that to happen. Just get governments and environmental special interests out of the way and that will happen so fast your head will spin. Until then don't plan on it.

CO2 sequestration may also be viable.

Depends on how you go about it, find an economic use for the CO₂ like expansion of agriculture & lumber production to lock up carbon and I can go for it. Once again there is no need for a "climate crisis" to justify, just good economic sense and get the government/enviro-politics folks out of the way. Growth in agriculture goes along with growth and economic advance of societies.

In essence, I know that the Kyoto Protocol is useless and indefensible (and you can research my numerous FR statements to that effect).

I've noticed, doesn't help to be arguing their battle for them though. The Kyoto folks are more than willing to implement their global political agendas on any pretext they can find. The global warming flap is just one of many such manufactured crisis they have tried to ride on for decades now.

But there are two reasons to pursue technology that will reduce fossil-fuel energy dependence: national economic security and climate change.

Nuclear power resolves both those issues quite well, and does not need a hyped up "global warming" crisis to justify it. Economics alone is more than sufficient. Your problem there rests with the same folks pushing the "global warming" Kyoto agendas. Seems they figure government controls over populations count for more towards their goals than technological and economic advances. You will please note how little credence these folks give towards advancing nuclear power as a element of their "solutions".

Oh yeah: correlation is not causation.

Variation of Solar irradiation cannot induce variation in the earth's Climate?

LOL, causation does assure a correlation will be present. If the effect is substantive, that correlation is measurable and verifies the causal physical processes at work.

Change the amount of direct incident energy input into a system and correlation is a direct measure of that physical process.

On the otherhand it has been shown that CO2 concentrations vary in response to global tempertature change, and have be shown not to be a prime cause of temperture variation for lack of any measure of statistical causality.

Many scientists have gone down that road and been misled.

They obviously can and do whenever one blindly accepts a correlation with a variable that has little or no physical basis for causation or is an affect as opposed to a cause.

We are speaking of solar irradiation, (i.e. direct energy) inputs with clear and obvious physical basis for independant effects on the system measured.

Solar activity is not some variation of variables caused by factors in the earths environment and haveas a direct and substantive bearing on the earths temperature directly as well as through radiant energy absorption of the primary GHG Water Vapor(95% of greenhouse effect).

In the case of the minority GHG gas CO₂(3.6% of greenhouse effect) causual effects cannot be demonstrated by statistical measure, quite the contrary, it has been shown that CO2 levels are an effect of temperature variation more than they are a cause of climate change.

CO2-Temperature Correlations

Consider, for example, the study of Fischer et al. (1999), who examined trends of atmospheric CO2 and air temperature derived from Antarctic ice core data that extended back in time a quarter of a million years. Over this extended period, the three most dramatic warming events experienced on earth were those associated with the terminations of the last three ice ages; and for each of these climatic transitions, earth's air temperature rose well in advance of any increase in atmospheric CO2. In fact, the air's CO2 content did not begin to rise until 400 to 1,000 years after the planet began to warm. Such findings have been corroborated by Mudelsee (2001), who examined the leads/lags of atmospheric CO2 concentration and air temperature over an even longer time period, finding that variations in atmospheric CO2 concentration lagged behind variations in air temperature by 1,300 to 5,000 years over the past 420,000 years."

[ see also: Indermuhle et al. (2000), Monnin et al. (2001), Yokoyama et al. (2000), Clark and Mix (2000) ]

"Other studies periodically demonstrate a complete uncoupling of CO2 and temperature "

[see: Petit et al. (1999), Staufer et al. (1998), Cheddadi et al., (1998), Raymo et al., 1998, Pagani et al. (1999), Pearson and Palmer (1999), Pearson and Palmer, (2000) ]

"Considered in their entirety, these several results present a truly chaotic picture with respect to any possible effect that variations in atmospheric CO2 concentration may have on global temperature. Clearly, atmospheric CO2 is not the all-important driver of global climate change the climate alarmists make it out to be."

Global warming and global dioxide emission and concentration:
a Granger causality analysis
http://isi-eh.usc.es/trabajos/122_41_fullpaper.pdf

"We find, in opposition to previous studies, that there is no evidence of Granger causality from global carbon dioxide emission to global surface temperature. Further, we could not find robust empirical evidence for the causal nexus from global carbon dioxide concentration to global surface temperature."

Here Comes the Sun

"Carbon dioxide, the main culprit in the alleged greenhouse-gas warming, is not a "driver" of climate change at all. Indeed, in earlier research Jan Veizer, of the University of Ottawa and one of the co-authors of the GSA Today article, established that rather than forcing climate change, CO2 levels actually lag behind climatic temperatures, suggesting that global warming may cause carbon dioxide rather than the other way around."
***
"Veizer and Shaviv's greatest contribution is their time scale. They have examined the relationship of cosmic rays, solar activity and CO2, and climate change going back through thousands of major and minor coolings and warmings. They found a strong -- very strong -- correlation between cosmic rays, solar activity and climate change, but almost none between carbon dioxide and global temperature increases."

Your "Oh yeah: correlation is not causation. " doesn't pertain to Solar inputs, which are, by physical necessity, prime causitive factors effecting the state of Earth's Climate.

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