TCS Daily

New Technologies and Global Warming Science

By Sallie Baliunas - October 15, 2001 12:00 AM

(Editor's note: These are edited remarks of Sallie Baliunas to the Ohio Energy Conference on Oct. 1, 2001)

Human use of coal, oil and natural gas has become the centerpiece in an international debate about global warming, its causes and its future path.

It is a fact that human consumption of fossil fuels has increased the amount of greenhouse gases, in particular the main one carbon dioxide, in the atmosphere. Greenhouse gases are essential to life on earth in that they help retain energy near the surface that would otherwise escape to space. Based on ideas about how climate works, the small additional energy resulting from additions of carbon dioxide should warm the planet.

Projections of future energy use, applied to the scientifically most advanced computer simulations of climate, have yielded wide-ranging forecasts of future temperature increases from a continued increase of carbon dioxide concentration in the air. These have been compiled by the United Nations' Intergovernmental Panel on Climate Change (IPCC). The middle range forecast of their estimates of future warming, based on expected growth in fossil fuel use without any curbs, is for a 1 degree Celsius increase between now and 2050. A simulation counting in the effect of the as yet unimplemented Kyoto Protocol, negotiated in 1997 and calling for a worldwide 5% cut in carbon dioxide emissions from 1990 levels, would reduce that increase to 0.94 C - an insignificant 0.06 C cut.


To achieve the cuts by 2012 as required under Kyoto, the United States would have to slash its projected energy use at that time by about 30 to 40%. Most economic studies indicate the costs of that would amount to more than $100 billion a year, to as much as $400 billion.

Is it worth it? Let's dissect the tension between an economic catastrophe occurring because of the implementation of Kyoto and the likelihood of an environmental catastrophe resulting from a failure to act.

New technological breakthroughs in climate science can help us put the issue in better perspective.

One key question that deserves an answer at the start of the debate is: What has been the response of the climate thus far of the climate to the small amount of energy added by humans from increased carbon dioxide in the air? To prove the reliability of their future forecasts, computer simulations need verification by how they've dealt with past temperature variability.

So let's look at the record of surface measurements.

In the 20th Century the global average surface temperature rose about 0.5 C. At first glance the warming seems attributable to human fossil fuel use, which increased sharply in the 20th Century. But a closer look at the 20th century temperature shows three distinct trends:

First, there was a strong warming of about 0.5 C beginning in the late 19th century and peaking around 1940. Then, oddly, there was a cooling from 1940 until the late 1970s. And the third trend showed a modest warming from the late 1970s to the present.

What makes this a little strange is that about 80% of the carbon dioxide from human activities was added to the air after 1940. Yet, the first substantial warming was before 1940. Then, as carbon dioxide expanded most rapidly, temperatures dropped for nearly 40 years, before rising then again since 1970s. The early 20th Century warming had to be largely natural. Human effects at most amount to about 0.1 C per decade - the maximum amount of the warming trend seen since the late 1970s.

But let's examine this maximum warming trend more closely.

First of all, climate simulations predict a smooth, linear rise should already be occurring, and will continue through the next century. If the warming trend has been 0.1 C per decade from human activities, then over 10 decades the forecast calls for at most 1 C warming by 2100. This amount of warming would be very similar to natural variability, with which man has dealt with for thousands of years. And it would essentially bring the climate to a level of warmth seen in the early centuries of the second millennium - a period which saw the settling of Greenland, Iceland, travel by the Vikings to Newfoundland, higher crop yields and generally rising life spans.

Secondly, though -- and here's the real rub against the models -- the recent trends in surface warming may not be primarily attributable to human action at all. Thanks to new space instruments and generous funding of about $18 billion in the last decade by American taxpayers into global research, we've learned some critical information indicating a lesser human effect on global climate change than the models project.

Computer simulations of climate predict readily detectable warming both of the surface and of the lowest layer of air above the surface - the lower troposphere - to a few kilometers altitude. Records from NASA's microwave sounder units aboard satellites, and validated independently by balloon radiosondes, show an absence of the forecast human-made warming trend. These troposphere records are essentially global, while those at the surface cover a mere fifth of the planet. The troposphere temperature does vary, such as with the strong El NiƱo warming pulse of 1997-98, but no meaningful human warming trend is seen.

Now proponents of the theory of human induced global warming argue that perhaps the human effect is masked in the lower troposphere because soot from sulfur dioxide and other so-called human-made aerosols cool the atmosphere. But that shading effect lacks substance, as the Southern Hemisphere, which is relatively free of aerosols, shows no long-term warming trend, period. That flatly contradicts the models' forecasts of significant human-made global warming and the hypothesis that aerosol pollutants are masking a significant human-made warming trend.


The radiosonde record from balloons that confirms the results of the satellites also confirms no trend of warming attributable to human activities. Only this record also extends back another 22 years -- to 1957. And although it lacks the dense spatial coverage from satellites, it shows no warming trend in global average temperature prior to a shift in 1976-77 - a warming known as the Great Pacific Climate Shift of 1976-77 that no one attributes to human causes but is a natural, periodic shift in the Pacific that affects global average temperatures.

So what is the result of looking at the very best data? When compared to the measurements, the output from computer simulations all forecast exaggerated warming trends. The forecasts exaggerate to some degree the warming at the surface, and decidedly in the lower troposphere. And since they've done that for the past several decades, the computer results presumably also exaggerate their forecasts of warming for the next century.

Is this a surprise? It isn't, not to scientists. The computer simulations of climate must track over 5 million parameters. To simulate climate change for a period of several decades is a computational task that requires 10,000,000,000,000,000,000 (10 million trillion) degrees of freedom. And they lack information on two major, natural greenhouse gas effects - water vapor and clouds. So it is not surprising that the predictions of future warming are unreliable.

Finally, in looking for sources of warming of the earth, a major one the models don't take fully into account is the influence of the Sun. The fact is that the 20th Century temperature pattern shows a strong correlation to energy output of the sun. Although the causes of the changing sun's particle, magnetic and energy outputs are uncertain, as are the responses of the climate to the sun's various changes, the correlation is pronounced. It explains especially well the early 20th century temperature rise, which cannot have much human contribution.

So what can we say about global warming and humans' contribution to it?

Based on the best temperature measurements of the last several decades, the actual response of the climate to the increased carbon dioxide content of the air has shown an insignificant man-made global warming trend. The magnitude of expected human change is especially constrained by the observed temperature trends of the lower troposphere.

This is good news. It means that the human global warming effect is small and slow to develop. That means there is plenty of time and opportunity to continue and improve observations and computer simulations of climate to better define the magnitude of human-made warming.

And what about human use of fossil fuels for energy that has added to the air's carbon dioxide concentration? Three things:

  1. No catastrophic human-made global warming effects can be found in the best measurements of climate. The alleged impacts haven't occurred. Hurricanes have not increased in the United Stats over the last half of the 20th Century; key infectious diseases such as malaria have been eradicated in the United States by the health, living and technological advances made in the last century.

  2. Energy use helped accomplish this last advance as it has also fed vast numbers of people while elevating them from poverty. The longevity, health, welfare and productivity of humans have improved with the use of fossil fuels for energy, and the resulting human wealth has helped produce environmental improvements beneficial to health as well.

  3. Carbon dioxide, the primary greenhouse gas produced by burning fossil fuels is not a toxic pollutant. It is, instead, essential to life on earth. Plants, including crops, have flourished owing to the aerial fertilization effect of increased carbon dioxide in the air. Agricultural experts estimate a 10% increase in crop growth in recent decades owing to the heightened concentration of carbon dioxide in the air.

Currently, fossil fuels provide around 84% of energy consumed in the United States, and roughly 80% of the energy produced worldwide. For the time being, they are key to improving the human condition. The scientific facts show the liberation of fossil fuels from their geologic reservoirs and mankind's use of them provide many economic, health and environmental benefits, whereas the environmental catastrophes forecast from their use by critics have yet to be demonstrated.

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