I picked up a copy of Scientific American to read on my flight to Copenhagen, intrigued by the cover teases for a “Portrait of a Black Hole” and “World Changing Ideas.” Settling into the packed flight from Dulles, which also carried John Holdren , the president’s science advisor, and Jane Lubchenco, the director of NOAA, I opened up the magazine to find a feature article on “Methane: A Menace Surfaces.” More than 20 years ago I addressed positive feedback loops between climate change and the global carbon cycle in my dissertation and a couple of subsequent scientific papers, so I couldn’t help but wonder how this important, but previously arcane, topic would be handled in a magazine aimed at a general audience.
The last time I had addressed this issue I relied on theoretical calculations to estimate the increase in emissions of heat-trapping gases from the Arctic tundra that could be spurred by future melting of the permafrost, prompting concern about positive feedback loops that would amplify the warming. Scientific American has pictures of the process actually occurring.
Calculations are still necessary to extrapolate from the observed increases in methane emissions to the extra global warming that this process could produce. Katey Walter Anthony, the author of the Scientific American article estimates this at 0.3 degrees Celsius. That may not sound like a lot, but the problem with positive feedback loops is that they amplify each other in a non-linear way. So this amount of extra warming from just this one process could spell catastrophe when combined with other positive feedback loops that are also already beginning to occur, such as increased carbon dioxide emissions from warmer soils and reduced carbon dioxide uptake by warmer seas.
Fortunately, the article on “World Changing Ideas” actually contained a number of ideas that could prevent the world from changing so much by reducing emissions of carbon dioxide. Interestingly, the idea at the top of that list is not a new gee wiz technology, but a way of financing purchases of available solar energy systems to spur their widespread deployment.
Of course, spurring widespread deployment of clean energy technologies is what the Copenhagen conference is all about. I haven’t yet made it to the official conference center (registration was closed on Sunday), but strolling around Copenhagen trying to reset my biological clock I once again could not escape the reason I’m here. While Copenhagen in December was chilly enough, I got a warm feeling from the fact that the issue of global warming is ubiquitous throughout the city, rather than just at the official conference venue. From huge displays in public squares to the conversation my cab driver started (when my legs gave out) about the mass protest that occurred here on Saturday, its obvious that concern about global warming is no longer confined to a few scientists making theoretical calculations about feedback loops.