Thursday, July 5, 2012

Global Warming Self-Perpetuating Events

One of the concerns about global warming is that there may be a “tipping point” temperature at which global warming could become more rapid and potentially unstoppable by human intervention. To date, a tipping point for global warming as a whole has not been identified. But at least two events linked to global warming do seem to have the potential to be self-perpetuating, triggering even further global warming.

One such self-perpetuating event is the thawing of glaciers, most notably in Greenland. Melting glaciers leave behind are newly exposed areas of land, sea, or dark melt-water pools, all three of which absorb more light energy than snow or ice. This causes more local warming, which in turn causes more melting, which then causes more warming, more melting, and so on. It’s like a positive feedback event, with no obvious end in sight.

Another potential self-sustaining warming event is thawing of the permafrost (land that is generally frozen all the time) at northernmost latitudes. The concern is that thawed permafrost will release large amounts of carbon dioxide and methane currently trapped in the frozen earth. Since both carbon dioxide and methane are greenhouse gases, this will further exacerbate global warming, leading to more thawing of permafrost, then more carbon dioxide and methane released…..

Will global warming as a whole become self-perpetuating? Right now, no one knows. Perhaps the best policy would be to try to control global carbon dioxide emissions soon so that if there is a tipping point temperature, we don’t exceed it.

No comments: