“The path of sound credence is through the thick forest of skepticism.”
—George Jean Nathan
The hallmark of science is to first generate a hypothesis, and then to design an experiment that will either confirm or refute that hypothesis. Repeated experimentation with consistent results helps to further strengthen the conclusions that are made. And although some people believe some “facts” do not require scientific study, history has shown us that we don’t always understand Mother Nature. For example, Galileo helped to prove that all things fall at the same speed and with the same rate of acceleration unless affected by air resistance. Until those experiments were completed, everybody simply assumed that heavier objects fell more quickly.
Sometimes you can’t do experiments to investigate a hypothesis, however. One reason would be that it’s unethical to do so. We’ve proven that smoking causes cancer because of careful observations over many decades, but it would be difficult as well as unethical to design a clinical trial where nonsmokers were randomized to either become smokers or remain nonsmokers, and then follow their health over the years. When such data needs to be obtained, we do our best to observe smokers and nonsmokers and compare how they do, and try to account for any other possible confounding variables that might affect the outcomes such as level of education, socioeconomic status, etc…
Climate change is the same as smoking in this regard. We can’t design a trial where we have control over a variable (such as carbon dioxide emissions) and then compare it to what the outcome would be if we eliminated those emissions. As it was with smoking, the best we can do is follow carefully to see what’s happening, and use the knowledge we have to try to account for any possible confounding variables that might also influence climate change. Variables such as changes in the sun’s irradiance, changes in Earth’s orbit, or other influences like volcanic eruptions and ocean oscillations such as El Niño.
The problem with such observations—whether for smokers or climate change—is that people are more likely to draw their own conclusions to suit their own needs, always arguing that the answer hasn’t been proven scientifically. We saw this phenomenon with smoking decades ago as the tobacco companies vigorously argued smoking did not contribute to cancer. They did this not for the sake of knowledge or understanding but rather for their own selfish purposes. And we see this happening now with many of the global warming deniers and skeptics who benefit from their financial gains within industries connected to fossil fuels.
So it’s particularly heartening to see some of these skeptics looking at the facts and believing the conclusions are quite clear, and that those who have argued that global warming is real and mostly due to our own human activities are indeed correct.
Case in point: the Charles G. Koch Charitable Foundation has contributed to the Berkeley Earth Surface Temperature Study (BEST), and BEST’s founder and scientific director is Richard Muller. It’s important to know that the Kochs are major funders of climate disinformation and that Muller has been a long-time skeptic of previous climate studies, even doubting that global warming was occurring at all. After last year’s intensive research by BEST which involved a dozen scientists, Muller stated “I concluded that global warming was real and that the prior estimates of the rate of warming were correct. I’m now going a step further: Humans are almost entirely the cause.”
The BEST data show that the average temperature of land on Earth rose 2.5 degrees Fahrenheit over the last 250 years, with 1.5 degrees over the last 50 years alone. The reason Muller is also convinced that human beings are the culprit is because the curve predicted by carbon dioxide emissions matches well with the observations. Nothing else has been able to explain the observations as closely.
Just as it was with smoking, this doesn’t necessarily prove that carbon dioxide is the absolute culprit, but it increases the robustness of that conclusion, and makes it harder to find an alternate explanation that can match the observations as well. In which case, skeptics and deniers will usually target the data, since they can’t offer better conclusions to explain the data observations. Mark my words.
If people look at facts and science with an open mind, the conclusions of the BEST study and what Muller now states are the simplest way to explain the observations. Many people have been saying the same thing for a decade or more, and new data consistently support those conclusions. But when skeptics start to reach this same level of understanding, it’s a sweet and encouraging moment in the journey our species is taking toward finding solutions to this problem.