Very often, when I talk to the public or the media about global warming (a low-frequency positive trend in global temperature in the last 120 years or so), they ask me the unfortunate question if I “believe” in global warming. And I say “unfortunate” because when we are dealing with a scientific problem “believing” has no place. In science, we either prove or disprove. We “believe” only when we cannot possibly prove a truth. For example, we may “believe” in reincarnation or an afterlife but we cannot prove either.
One may argue that when we are dealing with a scientific problem, such as global warming, for which we cannot obtain unquestionable experimental confirmation as to what is causing it (for the simple reason that we cannot repeat this experiment; we only have one realization of climate evolution), we may form an opinion based on the existing scientific evidence in hand, current knowledge, possible theories and hypotheses. But we should be skeptical of claims that the science of a complicated and unpredictable system is settled.
Nobody argues that the temperature of the planet is not increasing in the last 120 years or so. Yes, the temperature is increasing overall. But there are a lot of questions regarding why that is.
In the current state of affairs regarding global warming, opinion is divided into two major factions. A large portion of climate scientists argues that most, if not all, of the recent warming is due to anthropogenic effects, which originate largely from carbon dioxide emissions from the burning of fossil fuels. Another portion is on the other extreme: Those who argue that humans have nothing to do with global warming and that all this fuss is a conspiracy to bring the industrial world down.
The latter group calls the former group “the catastrophists” or “the alarmists,” whereas the former group calls the latter group “the deniers.” This childish division is complemented by another group, the “skeptics,” which includes those like me who question the extreme beliefs and try to look at all scientific evidence before we form an opinion (by the way, the former group also considers skeptics to be deniers).
In the realm of deniers, skeptics and believers, science has been compromised. I usually don’t bother with pseudo-scientists, media and ignorant people abusing the freedom of the Internet by writing and posting nonsense comments. But I have grown wary of what is going on with the debate on the overblown and misdirected issue of global warming — a case in point being “Meet the Press” host Chuck Todd saying he will no longer give time to global warming “deniers” and also that the “science is settled.”
The fact that scientists who show results not aligned with the mainstream are labeled deniers is the backward mentality. We don’t live in the medieval times, when Galileo had to admit to something that he knew was wrong to save his life. Science is all about proving, not believing. In that regard, I am a skeptic not just about global warming but also about many other aspects of science.
All scientists should be skeptics. Climate is too complicated to attribute its variability to one cause. We first need to understand the natural climate variability (which we clearly don’t; I can debate anybody on this issue). Only then we can assess the magnitude and reasons of climate change. Science would have never advanced if it were not for the skeptics. All model projections made for the 21st century failed to predict the slowdown of the planet’s warming despite the fact that carbon dioxide emissions kept on increasing. Science is never settled. If science were settled, then we should pack things up and go home.
My research over the years is focused on climate variability and climate dynamics. It is my educated opinion that many forces have shaped global temperature variation. Human activity, the oceans, extraterrestrial forces (solar activity and cosmic rays) and other factors are all in the mix. It may very well be that human activity is the primary reason, but having no strong evidence of the actual percent effect of these three major players, I will attribute 1/3 to each one of them.
Two final points. First, all the interactions of humans with the environment are part of our technological evolution. During this evolution, we could not go directly from living in the dark ages to a clean energy technology. There was no other way but to use fossil fuels and other pollution-producing agents. Is this enough to ruin the planet by altering the climate system, a system that has undergone major changes throughout the ages?
Second, while we should try our best to take care of our planet, global warming is not the only urgent planetary emergency. Overpopulation, poverty, infectious diseases and the effect of globalization in spreading them, the water crisis, energy and food availability and safety, political instability and terrorism, the global economy, even cyber security, are far more urgent problems with potentially catastrophic results for humanity.
• Anastasios Tsonis is emeritus distinguished professor at the University of Wisconsin-Milwaukee. He is the author of more than 130 peer reviewed papers and nine books.