Is Climate Change Driven by Mankind: My Personal Journey

The entire issue of anthropogenic climate change had its beginnings with the International Geophysical Year in 1958, for it was then that continuous observations of carbon dioxide were initiated from the Mauna Loa Observatory in Hawaii. As the time series of observations continued, the increasing concentration of this greenhouse gas in the atmosphere became apparent.

I recall that while I was taking graduate courses part time toward my doctorate at the University of Maryland in 1968, a conference on this subject was held to discuss the implications of this trend. Professor Helmut Landsberg, the Meteorology Department chairman, summarized the conference by saying that if the trend continued, he believed that the global climate would warm, although he was confident that mankind would be able to adapt to the changing climate just as we had in the past. There was no hint of either alarmism or prediction of catastrophe in his remarks.

By the mid-1970s, although the observed carbon dioxide concentration continued to rise, the so-called global temperature had been declining since the mid-1940s. It had even become fashionable for some scientists to claim that the Earth was entering a new ice age! Aerosols created by some “smokestack industries,” “slash and burn agricultural practices,” and “every step human beings take kicks dust into the atmosphere” were blamed. Of course, the media promoted the alarmism then just as it does today.

It was about that time that Professor Bert Bolin of Sweden proposed that perhaps enough carbon dioxide in the atmosphere might offset the cooling trend. Some scientists even proposed spreading carbon black on the ice sheets and glaciers to absorb more solar energy to aid in preventing the coming disaster!

One of the earliest alarmists who still believes that climate change is caused by mankind is, of course, Dr. James Hansen of NASA. In 1988, then-U.S. Senator Albert Gore, Jr. invited Dr. Hansen to testify before a Congressional Committee concerning his climate research. Dr. Hansen stated that “global warming is here now” (my paraphrasing).

At that time, I was working at NASA Headquarters, with responsibility for all of NASA’s weather and climate research programs (except those programs dealing with the stratosphere). Dr. Hansen’s revelation came as a surprise to me and my superiors at headquarters, as the official NASA position on climate change was that we did not understand the climate system, and more research was needed. For some time, global warming was not completely obvious to everyone, including me, because the thermometer observations did not agree with the satellite observations. As time went on, it became evident that the Earth’s climate was, indeed, undergoing a warming trend.

At first, I tended to accept that carbon dioxide was driving the warming trend. After all, carbon dioxide is a greenhouse gas and some very respected scientists were convinced that mankind’s burning of fossil fuels accounted for the rise in carbon dioxide concentrations in the atmosphere. Analyses of the global carbon dioxide budget claimed to confirm the view.

This is a stretch because global air-sea exchanges of carbon dioxide are poorly known. Many researchers had assumed that the Earth’s climate was balanced in a delicate, steady state, as though climate never changes. This alone should have sounded alarm bells, for those who fail to read history forget that as recently as a millennium ago, a Viking settlement had flourished in Greenland for nearly three centuries.

Despite the fact that worldwide thermometer observations of temperature are a relatively recent development on the time scale of written history, thermometer data are far from perfect. They are point measurements and provide incomplete coverage over the Earth. Satellite temperature observations are volumetric and provide complete coverage of the Earth, but have some limitations of their own. While proxy derivatives of historical temperatures and carbon dioxide concentrations obtained from ice cores, lake sediments, or tree ring growth are certainly useful, they involve certain assumptions, and thus have their limitations as well. It is also a fact that any data can be improperly analyzed or even manipulated, either intentionally or not.

My acceptance of anthropogenic global warming began to crumble when in the early 1990s, a brilliant young scientist, Professor Graeme Stephens of Colorado State University, came to my office and showed me the results of an investigation he had conducted using the community climate model at the National Center for Atmospheric Research (NCAR). Professor Stephens had inserted several cloud parameterization schemes developed by a climate modeling group in the U.K. into the NCAR climate model. He obtained model predictions ranging from two degrees of cooling to five degrees of warming!

Because the Earth’s radiation budget is dominated by variations in global cloud cover, this is one important reason why poorly simulated clouds in climate models produce nothing of value in the way of predictions. Professor Stephens’ experiment confirmed that we did not know enough about the radiative effects of clouds nor how to simulate them in climate models, and made the Cloudsat mission a top priority in my mind. I worked hard to win approval of the Cloudsat mission, although bureaucratic indecision delayed the launch for nearly a decade.

The world’s oceans store vast amounts of dissolved carbon dioxide. Thus, much of the increase in atmospheric carbon dioxide concentration we are witnessing could be a result of the warming of the surface layers of the oceans. It is a physical fact that gases dissolved in the seas are released when the temperature of the sea water rises. Rising carbon dioxide concentrations could well be caused by the warming climate, not vice versa. The role of solar activity in warming the climate cannot be ignored, nor can the long-term cyclic coupling of the atmosphere and oceans. However, I am convinced that mankind, by releasing greenhouse gases into the atmosphere and by changing land use, plays a very minor role in climate change compared to nature.

In the end, I believe that it is the reflection of solar energy back to space by global variations in cloudiness that dominates climate change. The causes of the variations in global cloudiness are somewhat speculative, but carbon dioxide concentration has no known role in affecting cloudiness. Of course, climate models also fail to simulate or even include other small-scale or slowly acting sub-grid processes as well, making their predictions anything but realistic.

On the positive side, increasing carbon dioxide concentrations promote plant growth, including crop yields, so more carbon dioxide is beneficial to mankind. As to the belief that computer models can forecast the Earth’s climate even a month from today, much less decades or even centuries into the future, appears to me to be a display of hubris of the first magnitude.

None of the climate models predicted the leveling off and cooling of the atmosphere that has occurred since 1998. This cooling has taken place even though the atmospheric carbon dioxide concentration has continued to rise. This fact, together with the work of Professor Fred Singer, has convinced me that climate models are far too sensitive to the greenhouse effectiveness of carbon dioxide. Water, as a vapor, is by far the dominant greenhouse gas, and as cloud droplets, snow, and ice crystals, it controls the Earth’s radiation budget.

In conclusion, our understanding of how the climate system works is still rudimentary, clearly not reliable enough to serve as the basis for government policy making. Policies that rely on climate model predictions call for reductions in carbon dioxide emissions to ameliorate the disaster that the models predict. Such policies will cost billions, if not trillions, of dollars and will have little, if any, effect on carbon dioxide concentrations or global climate change. Government policies should be focused on energy conservation and developing new energy sources that will reduce the free world’s dependence on imported energy.

The climate system is very complex, one in which small-scale and/or slow processes acting for a very long time can make huge differences in the forecast outcome. To believe that important climate processes, some of which occur on the molecular scale, can be realistically represented in a computer model requires a leap of faith. Science cannot be based on faith. It must be based on facts alone. Only religion requires faith of its believers.

References

Essex, C. and R. McKitrick: Taken by Storm, The Troubled Science, Policy and Politics of Global Warming, Key Porter Books, Toronto, Revised Edition, 356 pages, 2007.

Michaels, Patrick J.: Meltdown, The Predictable Distortion of Global Warming by Scientists, Politicians and the Media, Cato Institute, Washington, D.C., 271 pages, 2005.

Michaels, Patrick J. and Robert C. Balling, Jr.: Climate of Extremes, Global Warming Science They Don’t Want You to Know, Cato Institute, Washington, D.C. 267 pages, 2009.

Singer, S. Fred and Dennis T. Avery: Unstoppable Global Warming Every 1500 Years, Rowman & Littlefield Publishers, Inc. Lanham, Boulder, New York, Toronto, Plymouth, UK, 260 pages, 2007.

Spencer, Roy W.: Climate Confusion, How Global Warming Hysteria Leads to Bad Science, Pandering Politicians and Misguided Policies That Hurt the Poor, Encounter Books, New York, London, 191 pages, 2008.

Aerospace engineer John S. Theon is the former chief of NASA’s Climate Processes Research Program and its Atmospheric Dynamics & Radiation Branch, among other NASA positions. He was responsible for weather and climate research at the agency, including work by James Hansen, Roy Spencer, Joanne Simpson, and several hundred other scientists at NASA field centers, in academia, and in the private sector who worked on climate research. He retired from NASA in 1995 and served as a consultant to the agency between 1995 and 2008. He is co-author of the book Advances in Remote Sensing Retrieval Methods. He is a fellow of the American Meteorological Society and associate fellow of the American Institute for Aeronautics and Astronautics and has received numerous professional awards for his research. He holds degrees in aerospace engineering, meteorology, and engineering science and mechanics.