Those in denial about Anthropogenic Global Warming (AWG) frequently make a claim about a past prediction of global cooling rather than warming. The argument goes something like this: How can we trust the scientific community about their dire warnings of global warming when not that long ago they were warning about an impending ice age? What is it, warming or cooling? They don’t know.
The graph of the earth’s temperature between 1880 and now is bumpy to say the least, in scientific terms it is called a noisy signal. If you look at a short enough time period one can find both periods of warming and cooling. From about the 1940s to the 1970s there was a period of cooling; overall however, the trend is to warming. We are now about 2 degrees Fahrenheit warmer than 1880.
This brief period of cooling led to a number of studies focused on climate change. One significant discovery in this era was a climate driver known as “Milankovitch cycles.” This was a recognition of a certain wobble in the earth’s tilt and small changes in earth’s orbit. Whereas these cycles may have been important in past ice ages, they had little or nothing to do with the current changes in contemporary climate issues.
Another factor studied was particulate matter in the atmosphere. The brief cooling of the 40s-70s may have been impacted by larger than previous amounts of fine dust particles from burning fossil fuels. The dust actually caused reflection of sunlight, lowering the amount of light and heat that reached the surface of the planet. In fact, this has led some to the dangerous proposition of injecting dust into the atmosphere to combat AGW.
These were the discussions of scientists in the 1970s, where publishing in peer-reviewed journals is what goes for scientific discussions. A recent study, a peer-reviewed publication of course, looked at the number of publications in the 70s relating to changes in the earth’s climate. The authors of this study found there were only 7 papers predicting cooling, 20 predicting no change, and 44 predicting warming. The was never any consensus of global cooling, only a brief discussion.
The state of scientific publications now is a resounding consensus for global warming. The data is clear, the planet is getting warmer which is forcing changes to the climate. We know the warming is due to human activities because of correlations between warming and increases of greenhouse gasses in the atmosphere and deforestation.
Being skeptical about scientific findings is healthy. In that respect science is self correcting. Misunderstanding and outright fraud have been uncovered by questioning scientific results. But at some point when a consensus becomes clear, even overwhelming then the refusal to accept the consensus changes from healthy skepticism to dangerous denial.
Denial of AGW is hazardous as it allows some to justify inaction. The longer we wait, the more expensive will be our actions to mitigate damage. It is somewhat like a debt, the longer one waits to pay it off, the more costly it becomes. Inaction now just shifts greater costs to the future, our children.
Dr. Bob Allen, Ph.D., is Emeritus Professor of Chemistry at Arkansas Tech University.