Another high-profile skeptic of global warming has changed his mind. Physicist Richard Muller announced at the end of October that his team at the University of California at Berkeley
completed an analysis of climate data reaching back over 200 years. Their conclusion? The Earth has warmed more than one degree Celsius since 1950. Their findings, which are available online in a draft paper, confirm what the National Academy of Sciences and other scientific groups have been saying for years.
Muller’s findings are nothing new to climatologists, and they may not convince the entrenched climate change deniers who are more interested in ideology than observation. For the majority of non-expert fence-sitters, though, Muller’s work is extremely important, precisely because it shows the proper role for skepticism in climate research.
Muller is a respected scientist. Although his skepticism about the evidence for climate change has long been used by climate change deniers to bludgeon their opponents, he was more interested in pursuing the facts. He had worried that some weather stations (where the raw data on climate is collected) were more sophisticated or accurate than others. He had worried that the rise of massive cities in the past century could have skewed some of the results.
These were legitimate questions for a scientist to look at. Even though other teams of climatologists claimed they had accounted for such factors, there is nothing wrong with replicating research. That is one of the cornerstones of the scientific method. It’s the reason science is more useful than simple belief; no matter who does the experiment, they will get the same result.
Muller was prompted to embark on this study after the 2009 “Climategate” fiasco, in which an international team of climatologists were accused of changing data to fit with their understanding that the world was warming. Investigations into the team’s activities by multiple groups, including the British government, revealed that their data was solid. Nevertheless, politicians and average people, especially in the United States, were increasingly convinced that the world might not be warming. Muller’s study puts that scandal to rest.
Deniers still have some wiggle room. Muller says that he still isn’t sure whether or not the planet’s warming is being driven by humans, and his study did not answer that question. There will still be plenty of people who claim that global warming is entirely natural and that human emissions of carbon dioxide don’t matter. It’s sad that such a belief persists despite the fact that scientists have known for centuries that greenhouse gases change atmospheric temperatures. It was all the way back in 1896 that Swedish scientist Svante Arrhenius first pointed out that human emissions of carbon dioxide were warming the Earth.
Mounds of evidence have built on Arrhenius’s findings over the last hundred years. The basic mechanism that causes warming has never been contradicted, only refined. There are still real scientific questions to pursue. Will warming lead to increased clouds that offset some of the heat on the ground? Will reservoirs of methane (an even more potent greenhouse gas) trapped in frozen lakes push warming past some “point of no return” as the lakes thaw? How much carbon dioxide can the oceans absorb, and how will that impact sea life?
These problems are being worked on by scientists now. They may overturn some of our current understanding of the details, but they won’t change the fundamental role of human emissions. In the meantime, the rest of us need to stop fighting about whether or not global warming is real. The whole time that we’ve been embroiled in an unproductive ideological battle, the planet has been changing. We need to start applying skepticism to the right questions about how we will deal with a reality that does not care if we believe in it.
