The heat is on: "climate models ... overestimate the role of greenhouse gases and underestimate the role of ozone depletion."(Eye on Ecology)

• Author: Ward, Peter L.
• Position: Eye on Ecology

IN RECENT YEARS, a "consensus" of scientists has emerged claiming that greenhouse warming is the cause of climate change. Many have argued that this consensus means that the science of global warming is settled. Yet, science never is settled. Science advances every day by insights developed from new data and analysis.

Furthermore, "the work of science has nothing whatever to do with consensus," as author, screenwriter, and film director Michael Crichton explained in a 2003 lecture at the California Institute of Technology: "Consensus is the business of politics. In science, consensus is irrelevant. What is relevant is reproducible results. The greatest scientists in history are great precisely because they broke with the consensus."

Today's global-warming "consensus" has been crafted very carefully since 1988 by the Intergovernmental Panel on Climate Change, founded by the World Meteorological Organization and the United Nations Environment Programme. EPCC set out "to prepare a comprehensive review and recommendations with respect to the state of knowledge of the science of climate change."

In 1988, many scientists were convinced that observed global warming must be caused by observed increases in concentrations of greenhouse gases, which are known to absorb narrow bands of infrared energy radiated by Earth. Therefore, these gases must get warmer. This warmer air, then, has to, in some way, cause Earth to get warmer. The logic seems pretty clear.

These scientists felt the primary purpose of the IPCC, therefore, was to demonstrate a scientific consensus behind greenhouse-warming theory that was broad enough to convince politicians to make the difficult and expensive decisions to cut back greenhouse-gas emissions. They did not set out to find the true cause of global warming; they set out to prove consensus behind their favored theory. This strategy paid off in Paris on Dec. 12,2015, when representatives of 195 countries agreed to reduce greenhouse-gas emissions in an attempt to hold "the increase in the global average temperature to well below 2[degrees]C above pre-industrial levels and to pursue efforts to limit the temperature increase to 1.5[degrees] above pre-industrial levels."

This political effort by scientists would be a praiseworthy tactic if their favored theory turns out to be correct, but there is increasing evidence that causes many other scientists to wonder about greenhouse-warming theory. For example, the changes in the rates...