Stephen Schneider on avoidable and unavoidable climate impacts

Stephen Schneider: We can’t avoid the fact that there’s already a 400 percent increase in the area of wildfire in the U.S. West. That goes along with the fact that the summers are hotter, and the summers are longer as a result of the 1.4 degrees Fahrenheit warming we’ve already had.

Climate scientist Stephen Schneider of Stanford spoke about avoidable and unavoidable climate impacts at the March 2009 climate summit in Washington.

Stephen Schneider: But we can certainly avoid having it going to massive proportions by trying to keep the warming not much more than another 1 or 2 degrees. We don’t want to see it go to 4 to 6 to 8 degrees, where we could have not only catastrophic mega-fires, but also catastrophic mega-hurricanes.

He said hurricanes are more intense now than 40 years ago, with the evidence pointing to warmer oceans from global warming.

Stephen Schneider: But they’re only 10 or 15 percent stronger. Let’s not let them go to 40 percent. Let’s not let us get 3 or 6 degrees warming.

He said science can only access the risk.

Stephen Schneider: But what to actually do about that? It can be a decision about school boards trying to figure out whether to have new green schools, right up to national issues where we want to put a price on carbon or incentives to people to invent our way out of the problem. All of those levels are going to need the information that this kind of activity is going to provide though this activity will not answer the question what to do, because that’s a value judgment that society should make in a decision-making role.

Over the 20th century, Earth has warmed about 1.4 degrees Fahrenheit, said Schneider, mostly from the buildup of carbon dioxide released by burning fossil fuels. Looking ahead to a predicted two to six degrees of warming by the end of the 21st century, Schneider spoke of unavoidable climate impacts, such as melting of Arctic sea ice.

Stephen Schneider: And when you warm that area up, it then starts to threaten something of direct interest to all Americans who live in coastlines, which is a significant fraction of the country, which is if you start to melt the Greenland Ice Sheet, and that raises sea level many, many feet over the time frame of a century or two or three.

Schneider said that there might still be time to avoid the Greenland melt and other natural disasters from a warming climate such as ‘mega-wildfires’ in the western U.S. and ‘mega-hurricanes.’

Stephen Schneider: But I still think we have a pretty good shot at it if we start getting control of using the atmosphere as an un-priced sewer to dump our tailpipe and smokestack wastes.

Schneider said that climate change is unequivocal. He said there’s still time to prevent some of the most dangerous outcomes, but that we’ve got to get on with the job.

Under the auspices of the National Academy of Sciences, Schneider will be involved in a suite of research studies – scheduled for release in 2010 – called America’s Climate Choices.

Stephen Schneider: So there’s a lot that we still can avoid if we work at it. But we have to admit that there are some things that are already too late. And species moving around, and moving off the tops of mountains into extinction, we’re going to have some of that. But if we only warm up another degree or two, we’ll only have a minimum amount of it. Five per cent, that’s not good! That’s lots and lots, thousands and thousands of species. But if we warm up, four or six degrees, then we start looking at tens of percentages of species on Earth that we know about being threatened with extinction. This is a mega-catastrophe from the biological point of view, like an asteroid colliding with the Earth, like the kind that took out the dinosaurs and about 50 percent of species. We can avoid that. We just have to get on with the job.

Our thanks to:
Stephen Schneider
Stanford University
Stanford, CA

April 16, 2009

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