The Flipping Point (global warming conversion of skeptic Michael Shermer)

Scientific American ^ | June 2006 | Michael Shermer

[cogitator]

The Flipping Point

How the evidence for anthropogenic global warming has converged to cause this environmental skeptic to make a cognitive flip

By Michael Shermer

In 2001 Cambridge University Press published Bjørn Lomborg's book The Skeptical Environmentalist, which I thought was a perfect debate topic for the Skeptics Society public lecture series at the California Institute of Technology. The problem was that all the top environmental organizations refused to participate. "There is no debate," one spokesperson told me. "We don't want to dignify that book," another said. One leading environmentalist warned me that my reputation would be irreparably harmed if I went through with it. So of course I did.

My experience is symptomatic of deep problems that have long plagued the environmental movement. Activists who vandalize Hummer dealerships and destroy logging equipment are criminal ecoterrorists. Environmental groups who cry doom and gloom to keep donations flowing only hurt their credibility. As an undergraduate in the 1970s, I learned (and believed) that by the 1990s overpopulation would lead to worldwide starvation and the exhaustion of key minerals, metals and oil, predictions that failed utterly. Politics polluted the science and made me an environmental skeptic.

Nevertheless, data trump politics, and a convergence of evidence from numerous sources has led me to make a cognitive switch on the subject of anthropogenic global warming. My attention was piqued on February 8 when 86 leading evangelical Christians--the last cohort I expected to get on the environmental bandwagon--issued the Evangelical Climate Initiative calling for "national legislation requiring sufficient economy-wide reductions" in carbon emissions.

Then I attended the TED (Technology, Entertainment, Design) conference in Monterey, Calif., where former vice president Al Gore delivered the single finest summation of the evidence for global warming I have ever heard, based on the recent documentary film about his work in this area, An Inconvenient Truth. The striking before-and-after photographs showing the disappearance of glaciers around the world shocked me out of my doubting stance.

Four books eventually brought me to the flipping point. Archaeologist Brian Fagan's The Long Summer (Basic, 2004) explicates how civilization is the gift of a temporary period of mild climate. Geographer Jared Diamond's Collapse (Penguin Group, 2005) demonstrates how natural and human-caused environmental catastrophes led to the collapse of civilizations. Journalist Elizabeth Kolbert's Field Notes from a Catastrophe (Bloomsbury Publishing, 2006) is a page-turning account of her journeys around the world with environmental scientists who are documenting species extinction and climate change unmistakably linked to human action. And biologist Tim Flannery's The Weather Makers (Atlantic Monthly Press, 2006) reveals how he went from being a skeptical environmentalist to a believing activist as incontrovertible data linking the increase of carbon dioxide to global warming accumulated in the past decade.

It is a matter of the Goldilocks phenomenon. In the last ice age, CO2 levels were 180 parts per million (ppm)--too cold. Between the agricultural revolution and the industrial revolution, levels rose to 280 ppm--just right. Today levels are at 380 ppm and are projected to reach 450 to 550 by the end of the century--too warm. Like a kettle of water that transforms from liquid to steam when it changes from 99 to 100 degrees Celsius, the environment itself is about to make a CO2-driven flip.

According to Flannery, even if we reduce our carbon dioxide emissions by 70 percent by 2050, average global temperatures will increase between two and nine degrees by 2100. This rise could lead to the melting of the Greenland Ice Sheet, which the March 24 issue of Science reports is already shrinking at a rate of 224 ±41 cubic kilometers a year, double the rate measured in 1996 (Los Angeles uses one cubic kilometer of water a year). If it and the West Antarctic Ice Sheet melt, sea levels will rise five to 10 meters, displacing half a billion inhabitants.

Because of the complexity of the problem, environmental skepticism was once tenable. No longer. It is time to flip from skepticism to activism.

[elvisabel78]

It shows a direct relationship between man-caused emissions and atmospheric concentrations of co2.

[Old Professer]

I have often mused that if CO2 requires the use of a molecule of oxygen added to a single carbon atom could it be argued that the mass of the atmosphere is increasing overall by the carbon overload and has anyone tried to measure this or the small but significant reduction in free oxygen?

[Old Professer]

Not at all; it assumes that every addition contributed by man remains and we both know that it is impossible to quantify the emissions over 200 years.

When we first measured the air we had about 280ppm; 200 years later we see 380; we know the diameter of the earth within a few miles and the height of the atmosphere as well as the weight in pounds, shekels and promises but the importance in the past with atmospheric weight is that it could be useful as a harbinger of weather, to now pretend that it is a bellwether for climate as well is a leap of faith.

[elvisabel78]

Maybe this confusion is based on you not clearly explaining what it was that you did not find in any real study.
can you restate it?

[Steve Van Doorn]

Yes we know CO2 OFTEN goes up and down with temperature but not always.

[Steve Van Doorn]

Could you look at post number 196 and explain to me how the earth had over 12X more CO2 then we have today and was colder then it is today?

[elvisabel78]

The member who was having a discussion with me, prior to your arrival, had an opinion that it "he and I knew" that it is impossible to know the amount of co2 in the last 200 years".
Now you show me a graph claiming to know the amount of co2 thousands and thousands years ago.
But let's assume your estimate of the amount of co2 was accurate thousands and thousands of years ago:

Nasa came to the general conclusion in their study that the sun may have played a dominant role in pre-industrial climate change (from 1600 to 1800, for example) but it has not played a significant part in long-term climate change during the past few decades.

link

In other words, like Nasa said, Solar output had a very significant relationship in those little glacial ages that you showed in your graph from thousands and thousands years ago. Low solar output=extreme cold.
Then we have a similar conclusion from the National Academy of Sciences of the US:

The evidence of periods of several centuries of cooler climates worldwide called "little ice ages," similar to the period anno Domini (A.D.) 1280-1860 and reoccurring approximately every 1,300 years, corresponds well with fluctuations in modeled solar output.

link

Now look at this graph and note how solar output is decreasingly having an effect in global warming, suggesting that man-caused greenhouse gases such as co2 emissions are the problem:

[Dominic Harr]

It's been 'warming' since the end of the last ice age.

Clearly.

Therefore, it's impossible for modern equipment to be the cause.

Seems simple enough.

Cars cause global warming like silicon breast implants cause health problems. The media whips people into a frenzy by publishing data without any context, then demands something be done.

• We must do something
• This is something
• Therefore, we *must* do this

[elvisabel78]

OH and i didn't even mention the changes in the earth's axial tilt (Milankovitch cycles) that occasionally occur in our planet, and that Scientists say have been a major factor in the glacial periods that may have appeared in the graph contained in post 196.

[Steve Van Doorn]

Dr Christopher R Scotese states how he collected the information for the graph (in post 196):
We can determine the past climate of the Earth by mapping the distribution of ancient coals, desert deposits, tropical soils, salt deposits, glacial material, as well as the distribution of plants and animals that are sensitive to climate, such as alligators, palm trees & mangrove swamps.

For more information on this: http://www.scotese.com/climate.htm

”Now look at this graph and note how solar output is decreasingly having an effect in global warming, suggesting that man-caused greenhouse gases such as co2 emissions are the problem:”

How does this suggest that man created this? The first thing I notice in your graph was during WWII when man was at our highest level of pollution the temperature went down. All this graph shows me is there are other forces acting on the earth to create the change in temperature. We know it isn’t CO2 because we can mathematically calculate the amount of temperature gain.

Should we figure out what it is? YES Should we point fingers before we figure that out? You tell me.

I would first suggest we look at other planets in the solar system to see what they might be doing. We do know that Mars and Pluto are warming up in the past few years.

[Steve Van Doorn]

there are many different cycles some lasting tens of thousands of years long. All the more reason to not look at short term graphs under 1000 years.

It is interesting to note on cycles we found tropical plants in Antarctica.

[jonrick46]

The effects of solar irradiance on climate is just recently being investigated. We know that sun spots vary week to week and also follow an eleven year cycle. It is now accepted that sun spot activity is connected to solar output (irradiance).

The changes in solar irradiance over the long term is not known yet, because irradiance data has only been available for the last 20 years. Even the method of measuring the changes in irradiance have only recently been agreed upon. What is beginning to be understood is the huge effect of these relatively small changes in solar output on precipitation and ultimately, climate.

We do have long term historical data about sun spot activity. If the correlation with sunspots is true, then by using the historical information about sun spots, we can look at climate changes. For example, between 1945 and 1715 there is record showing low sun spot activity. During this period, there was record low temperatures on the earth. Since that mini ice age, the earth has been on a 300 year warming trend. Sun spot activity has gone through a similar increase with the peak in 1960.

Solar irradiance levels go through relatively small fluctuations. How can such small changes affect climate in such big ways? Absorption of solar energy by the tropical oceans create ocean-temperature anomalies that are transported by ocean currents over a period of time to locations where the ocean temperature can modify the North American jetstream in position and strength. Such action in turn determines precipitation patterns. This influence on the jetstream is the key to the climate change. Only recently is the jetstream being understood in its role in climate change and global warming. When it is fully understood all the influences affecting the behavior of the jetstream we may then find that the human impact is not really the culprit. So far we are finding that the primary influence on the jetstream points more and more to the natural fluctuations of the sun's output; something that man has little control.

[Wonder Warthog]

"Do you have a source for this"

http://www.clearlight.com/~mhieb/WVFossils/Carboniferous_climate.html

Scroll down the page a bit.

[Smokin' Joe]

Even given that the globe is warming, the evidence that man is the cause is pretty shaky. But then, liberals tend to be consumed with guilt, anyway...all it needs is a focus.

[Hardastarboard]

Look at the weather forecast on Yahoo several times a day. Educated meteorologists can't even tell me what the G-d D@mn temperature is going to be each day within one degree, and when or whether it's going to rain, and they have ALL of the data necessary at hand to determine that.

[elvisabel78]

If there is an evidence that is weak is the evidence on the theory of solar output causing the increasing temperatures in recent decades. And this has been proven by directly measuring solar radiation, which we couldn't do in the past. The U.S Global Climate Change Research Program says it. A group commissioned by Bush to investigate global warming says it. Most scientists say it.

[Smokin' Joe]

It could just as well be that obscurants from burning rain forests, (and cities in WW-II) as well as general "soot", put a blip in what would otherwise be a general warming trend, as shown in the historical record that you posted above.

The blip extends from roughly 1945 to 1986 and coincides, roughly, with the duration of atmospheric nuclear testing.

[Smokin' Joe]

How long have we been doing this, exactly?

[Valin]

Thanks again. Who knows I might actually learn shudder something.

[palmer]

But increasing the CO2 content of the atmosphere undoubtedly causes the climate to warm; and back before C4 photosynthesis evolved, we undoubtedly had much higher atmospheric CO2 and a warmer climate.

Running the numbers yields a 0.6 C increase for the current 350ppm CO2 (increased from 280). The highest projected increase in CO2 (which IMO is unlikely) yeilds another 1 degree C. The rest of the warming from the alarmists comes from models showing water vapor. Most of the warming from those models requires water vapor to be much more evenly distributed than is currently the case or possible in the future. To spin it more, the alarmists claim the water vapor will wind up in the stratosphere where it will cause the most warming. However, they don't like to talk about weather since that's how the water vapor will be distributed and how most of the stratospheric water vapor will get there.

Why don't they talk about weather? Because they can't model it in enough horizontal and vertical detail to get a meaningful idea about its effect.