It’s 95 Percent Certain That We’re the Main Cause of Climate Change

Every few years, since 1990, an international team of thousands of scientists, supported by the United Nations, has put together a massive report compiling and analyzing and interpreting pretty much everything we know about climate change. In the most recent one—the Intergovernmental Panel on Climate Change’s Fourth Assessment Report, or the IPCC AR4, released in 2007—the scientists concluded that the world is warming and that the change is being spurred by rising atmospheric concentrations of greenhouse gases. They also said that we’re largely to blame.

Set to be released next year, the IPCC’s Fifth Assessment Report, IPCC AR5, builds on what we’ve learned since that last report and, according to the New York Times, a leaked early draft of that report is even more firm about our role in changing the planet:

The 2007 report found “unequivocal” evidence of warming, but hedged a little on responsibility, saying the chances were at least 90 percent that human activities were the cause. The language in the new draft is stronger, saying the odds are at least 95 percent that humans are the principal cause.

The report is still a draft, but it seems very unlikely that this strong stance on humans being the driver of modern climate change is going to go away. As Smart News wrote previously, 97.1 percent of climate scientists say that their work supports the idea of human-caused climate change.

The other key thing to notice is the language used: “95 percent that humans are the principal cause” of modern climate change . That means that we and our activities are the main driver of climate change. Even if that last remaining 5 percent of scientific uncertainty somehow comes through and some other aspect of the climate turns out to be the main driver of modern warming, we’ll still be partially responsible for driving climate change. We’ll just be the second biggest bully on the block.

More from Smithsonian.com:

A Friendly Reminder From Pretty Much Every Climate Scientist in the World: Climate Change Is Real

Colin Schultz | | READ MORE

Colin Schultz is a freelance science writer and editor based in Toronto, Canada. He blogs for Smart News and contributes to the American Geophysical Union. He has a B.Sc. in physical science and philosophy, and a M.A. in journalism.