NASA Study Finds World Warmth Edging Ancient Levels

A new study by NASA scientists finds that the world's temperature is reaching a level that has not been seen in thousands of years.

The study, led by James Hansen of NASA's Goddard Institute for Space Studies, N.Y., along with scientists from other organizations concludes that, because of a rapid warming trend over the past 30 years, the Earth is now reaching and passing through the warmest levels in the current interglacial period, which has lasted nearly 12,000 years. An "interglacial period" is a time in the Earth's history when the area of Earth covered by glaciers was similar or smaller than at the present time. Recent warming is forcing species of plants and animals to move toward the north and south poles.

The study used temperatures around the world taken during the last century. Scientists concluded that these data showed the Earth has been warming at the remarkably rapid rate of approximately 0.36° Fahrenheit (0.2° Celsius) per decade for the past 30 years.

"This evidence implies that we are getting close to dangerous levels of human-made pollution," said Hansen. In recent decades, human-made greenhouse gases have become the largest climate change factor. Greenhouse gases trap heat in the Earth's atmosphere and warm the surface. Some greenhouse gases, which include water vapor, carbon dioxide, methane, nitrous oxide, and ozone, occur naturally, while others are due to human activities.

The study notes that the world's warming is greatest at high latitudes of the Northern Hemisphere, and it is larger over land than over ocean areas. The enhanced warming at high latitudes is attributed to effects of ice and snow. As the Earth warms, snow and ice melt, uncovering darker surfaces that absorb more sunlight and increase warming, a process called a positive feedback. Warming is less over ocean than over land because of the great heat capacity of the deep-mixing ocean, which causes warming to occur more slowly there.

Hansen and his colleagues in New York collaborated with David Lea and Martin Medina-Elizade of UCSB to obtain comparisons of recent temperatures with the history of the Earth over the past million years. The California researchers obtained a record of tropical ocean surface temperatures from the magnesium content in the shells of microscopic sea surface animals, as recorded in ocean sediments.

One of the findings from this collaboration is that the Western Equatorial Pacific and Indian Oceans are now as warm as, or warmer than, at any prior time in the Holocene. The Holocene is the relatively warm period that has existed for almost 12,000 years, since the end of the last major ice age. The Western Pacific and Indian Oceans are important because, as these researchers show, temperature change there is indicative of global temperature change. Therefore, by inference, the world as a whole is now as warm as, or warmer than, at any time in the Holocene.

According to Lea, "The Western Pacific is important for another reason, too: it is a major source of heat for the world's oceans and for the global atmosphere."

In contrast to the Western Pacific, the researchers find that the Eastern Pacific Ocean has not shown an equal magnitude of warming. They explain the lesser warming in the East Pacific Ocean, near South America, as being due to the fact this region is kept cool by upwelling, rising of deeper colder water to shallower depths. The deep ocean layers have not yet been affected much by human-made warming.

Hansen and his colleagues suggest that the increased temperature difference between the Western and Eastern Pacific may boost the likelihood of strong El Ninos, such as those of 1983 and 1998. An El Nino is an event that typically occurs every several years when the warm surface waters in the West Pacific slosh eastward toward South America, in the process altering weather patterns around the world.

The most important result found by these researchers is that the warming in recent decades has brought global temperature to a level within about one degree Celsius (1.8°F) of the maximum temperature of the past million years. According to Hansen, "That means that further global warming of 1 degree Celsius defines a critical level. If warming is kept less than that, effects of global warming may be relatively manageable. During the warmest interglacial periods the Earth was reasonably similar to today. But if further global warming reaches 2 or 3 degrees Celsius, we will likely see changes that make Earth a different planet than the one we know. The last time it was that warm was in the middle Pliocene, about three million years ago, when sea level was estimated to have been about 25 meters (80 feet) higher than today."

Global warming is already beginning to have noticeable effects in nature. Plants and animals can survive only within certain climatic zones, so with the warming of recent decades many of them are beginning to migrate poleward. A study that appeared in Nature Magazine in 2003 found that 1700 plant, animal and insect species moved poleward at an average rate of 6 kilometers (about 4 miles) per decade in the last half of the 20th century.

That migration rate is not fast enough to keep up with the current rate of movement of a given temperature zone, which has reached about 40 kilometers (about 25 miles) per decade in the period 1975 to 2005. "Rapid movement of climatic zones is going to be another stress on wildlife," according to Hansen. "It adds to the stress of habitat loss due to human developments. If we do not slow down the rate of global warming, many species are likely to become extinct. In effect we are pushing them off the planet."

It is foolish in the utmost to assume that human activity is responsible for climate change and then attempt to mitigate the climate. Why? Simply because at this point it remains to be proved that humans are responsible for climate change.

There is an increasing body of data indicating the strong likelihood of anthropogenic causation of the current warming trend.

You provide a nice summary of recent global climate.

It is signal to me that not a single climatologist, who today cares so much for our climate, cares to test his models and theories on the climate change that enabled Erik the Red to settle Greenland, or the climate change that froze the River Thames.

But they certainly do! And there is fairly widespread agreement that the LIA was primarily due to a period of slightly lower solar activity called the "Maunder Minimum". The earlier Medieval Warm Period, with strongest effects observed in the North Atlantic region, was a naturally warm period with potential (slight) augmentation due to ocean circulation variability.

1) To what extent is the climate really changing;
2) To what extent is human activity responsible for any change that is harmful;
3) To what extent, and at what cost, can humanity mitigate their behavior to reduce or eliminate any harmful climate change.

1) It's getting warmer.
2) Harm remains to be seen. Human activity is indicated to be responsible for the majority of the current warming trend.
3) My conservative answer is that the response of "humanity" shouldn't be focused on reducing CO2 emissions (as the Kyoto Protocol did). It should be about improving the global energy infrastructure to improve efficiency and provide the benefits of increased energy availability while reducing the global (and national) dependence on fossil fuels. The U.S. will benefit in terms of economic stability and national security if dependence on foreign oil resources is reduced; if that happens, the benefits to the climate will accrue as a consequence.

theBuckwheat wrote:

"-- It is foolish in the utmost to assume that human activity is responsible for climate change and then attempt to mitigate the climate. Why? Simply because at this point it remains to be proved that humans are responsible for climate change.

Cogitator replies by essentially 'begging the issue' instead of responding with debate:

But they certainly do!
There is an increasing body of data indicating the strong likelihood of anthropogenic causation of the current warming trend.

Buckwheat also provided a nice summary of ~why~ there is an increasing body of socalled data that indicates the "strong likelihood of anthropogenic causation of global climate changes". - He wrote:

"--- That climate change doesn't get grants approved, and that climate change will not allow socialists to increase the size of government along with permeating the regulatory system into every area of our daily lives to such an extent that we will have to ask government for permission to use energy. ---"

Your failure to even acknowledge that comment is a bit telling, imo.. As is your avoidance of his question:

"-- To what extent is human activity responsible for any change that is harmful --".

2) Harm remains to be seen.

Obviously, -- which leaves the question of ~why~ political action must be taken ~now~ to improve the "global energy infrastructure"..
-- Buckwheat & I, and many others see a political agenda here. -- You cannot?

… climate change, based upon inferences from the geological record, is a phenomenon that transpires over hundreds, if not thousands, of years…

This statement is also incorrect… It should be fairly obvious that the processes which control climate on time-scales of thousands to millions of years are different than those which affect climate on time-scales of decades to centuries.

If I accept your assertion as valid for the sake of discussion (a issue on which I am, as yet, unwilling to accept in reality), then your burden of proof escalates. For example, your model must explain how it is that all record high temperatures have not occurred with the last decade or how record lows could be recorded in the same decade, etc. For that matter. how there could there be temperatures even close to record highs in the 1940’s or close to record low’s in the 1990’s? If you are going argue that such are the vagrancies of localized variation, then you must reduce the number of decades for which you can claim to have valid data as worldwide weather data gathering did not exist until well into the twentieth century. As a matter of fact, there were few reporting stations in parts of the world other than the US, Europe and, perhaps, China and Japan prior to the 1920’s and even into the 1940’s and 1950’s for truly remote areas.

If you choose to define climate on a time scale of decades (let’s assume 3 decade intervals for the sake of discussion), then your model, to which you linked earlier, has only 4 such periods. Statistically, such a small number of samples cannot yield meaningful results. Consequently, you still have not met the test of statistical validity to support any of your conclusions or prove that your model has any undisputable, predictive capability.

I have challenged you in a number of different ways on the issue of statistical validity several times, but you have yet to address it. Beyond failing to address the statistical validity challenge you have also ignored a similar challenge to the source of your data (actual measures not estimates or assumptions) and the accuracy and precision of such.

Logically, if you are concerned about climate changes defined by decades, then your postulated cause and effect correlations must be adjusted. This adjustment must mathematically filter out those influences that are supposedly responsible for the longer-term changes that you cite such as are reflected in the inferred temperature records in ice core drillings. Neither your explanations nor your model appears to accomplish such a mathematical filtering.

Now that a temperature increase is being observed, the cause of the increase must be partitioned into natural or anthropogenic forcing. In the current climate state, natural factors are insufficient to explain the increasing trend, even though the current temperatures may be slightly less than the maximum Eemian peak temperatures.

As you, yourself, admit with the above statement, the current interglacial period contains no temperatures greater than some inferred from ice core samples in previous interglacial periods thousands of years ago. Consequently, you must establish how much of the current temperature increase (called global warming) is due to the same causes as previous interglacial temperature increases and how much is due to your postulated “anthropogenic” causes. As I have pointed out previously, neither you, nor anyone else, can accomplish this task because there is no data (measures as opposed to estimates and assumptions) for solar activity, volcanic activity, or other potentially climate driving phenomena, etc., for the previous interglacial periods.

My point still stands: There are no data, i.e., measurements, of worldwide, volcanic contribution to the gaseous composition of the atmosphere.

Your point is specious. There is sufficient data to determine the amount of CO2 contributed by volcanoes. If the estimate was way off, the Keeling CO2 curve (measured on Mauna Loa) would not conform to the well-determined CO2 production budget.

Very well, I challenge you to tell me what the measured, gaseous contribution to the atmosphere of the Krakatoa eruption (postulated to be the largest volcanic eruption in several centuries) in 1883 was. That year is within your model’s listed time frame. Did that particular eruption correspond to the “Keeling CO2 curve (measured on Mauna Loa)”? Better yet, what was the temperature in the Yucatan, Katmandu or Diego Garcia that year and how did the eruption affect them compared to previous years?

Perhaps, you could tell me what the cause of the “Little Ice Age” was and support your conclusion with measurements instead of estimates and assumptions? Alternately, how about revealing the climatic cause of the “year without a summer,” 1816, similarly supported by measured data.

Please note that Sputnik was launched in 1957 which is commonly referred to as the beginning of the satellite age. Therefore, my statement is not Incorrect again.

Excellent hairsplit. Usually the reference to satellites in regard to ozone refers to when ozone measurements from satellite-borne sensors began.

Far from a hair split, my first statement, which you called incorrect, was merely a sound historical citation with a perfectly understandable English sentence. That sentence referred to the fact that there had been no measurements of the “ozone hole” confirming or denying its existence prior to 49 years ago. That anomaly could have existed for centuries for all that can be proven with measurements.

Correction: the hole in the ozone is absolutely and unequivocally due to CFCs and their breakdown byproducts…It took time for the CFCs to reach the stratosphere in sufficient concentrations for the ozone-destroying reactions to affect stratospheric ozone concentration.

Your unequivocal assertion above is a good example of why the claims concerning climate change are considered so dubious by many. While there can be no argument that a photo-chemical reaction can occur that would change CFC’s into “ozone eaters,” it is a far cry from mere possibility to actuality. CFC’s manufacture began in 1928, as I recall from my reading, and was nearly exclusive for most of the time, and the vast bulk, of its manufacture decades later, to the northern hemisphere. Consequently, it is a rather large leap to cite CFC’s as the cause of an “ozone hole” at the south pole. It is even more curious that there is no comparable “ozone hole” in the artic. The situation is especially puzzling since the prevailing wind patterns split at the equator and circulate hemi-spherically in opposite directions to the respective poles and back to the equator. Add to this, that, again, the bulk of the CFC manufacture was in the northern hemisphere meaning, logically, the bulk of the concentration of ozone “eating” should have been in the same hemisphere. I have read some rather tortured, attempted explanations for that phenomenon, but, in the end, the result was just too tortured to be credible. The net result has been another “hole” in the global-warming-climate-disaster argument.

The "mainstream" climate science community has over the past few years become increasingly convinced of the main reasons for the observed climate signals. Scientists don't like to phrase their understanding as "absolute certainty" -- they'd probably prefer "strong probability". Anyway, most of them indicate that the probability is strong enough that it is time to start planning effective responses.

Call me a skeptic, but I refuse to take the “climate science community’s” word when their arguments are mathematically unsupported at the most basic statistical level. If the conclusions are couched in terms of probability, then I want to see the confidence limits, the regression coefficients, the raw data, etc. Unfortunately, such is not forth coming for time frames more than about 50 or 60 years ago (ice ages and interglacial periods last thousands of years). Yet, we are asked to accept “probability” conclusions based upon estimates (again without confidence limits) and assumptions (once more, without confidence limits).

Probabilities are such that when two or more things must exist simultaneously for a postulated outcome, the probability of that outcome is the product of the starting probabilities. Since the probabilities under discussion are all less than one, multiplying them together produces an even smaller number for the resulting probability. Furthermore, the degree of uncertainty associated with model forecasts becomes greater with cumulative uncertainties associated with the inputs. Therefore, starting with estimates and assumptions is inadequate for anything requiring action that is going to have potentially huge, negative economic impacts.

How does one honestly debate when the advocacy side cannot be fully honest and transparent as to their issues or even the data?

I cannot respect any climate model where the author refuses to consider previous episodes in climate history that would help in validation. If there is any begging going on here, how these models backtest against the Little Ice Age, for example, just begs to be done.

Such backtesting appears to be an unnecessary step for True Believers of Global LukeWarming. What counts is the future, not the past. Yet until the science is well established, as far as I am concerned, a model is not a fact, it is a form of fancy speculation. But True Believers always speak confidently and authoritatively about the future based on their most recent model, that is until it is superseded by next month's model.

But we are not debating some obscure issue that does not have any effect on our lives or the lives of our children. Just today, the Governor of California signed a law to cap and regulate a carbon dioxide, a gas that every human produces. This is such dangerous silliness that I would urge anyone who can to move out of the state at the earliest moment they can settle their affairs there and find employment elsewhere.

At the very least it is silly because we cannot measure any effect, we cannot know if anyone is cheating or complying simply because we cannot sequester California air to measure any compliance or violations. The only thing the state can do is the usual clumsy, ham-handed, broad-stroke regulation and enforcement that governments specialize in.

If Acts of Nature (or Nature's God) emit carbon dioxide, what shall the State do? Issue a citation? ROFL.

I hate to think how much CO2 is being emitted by the current brush fire. But government will not count any emissions of CO2 by that DC10 air tanker they are employing. No, government will find ways to exempt itself from the cap and limits.

Nor will it count any CO2 emissions that are out-sourced. Just like emissions from lead smelting are now out-sourced to countries where the pollution doesn't matter, when a businessman makes a rational decision to alter where he builds things or burns things, the net result is often to move that activity where there are no controls or regulations, resulting in a greater ecological burden, not a lesser one.

So, even though the debate about the human causes of climate change is still unsettled, we now see governments taking concrete steps that have concrete effects on our liberties and on the cost of living. It is legislation based on look-good, feel-good instead of sound science. The advocates of Global Warming cannot say they are not responsible. Indeed, many cheer California's new law. I have not seen one word in the press about caution or alarm that this law is premature.

This shows that advocates are not honest about the issue. I cannot allow myself to be engaged in a debate where the other side will not be honest. The game is rigged. No matter what I say, no matter what I prove, no matter what facts I bring to light, nor what flaws in the other side's theory I discover, it will never be enough to alter their position. Global Warming is an established fact in their minds and that is that.

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