Today is Blog Action Day ’09, “an annual event held every October 15 that unites the world’s bloggers in posting about the same issue on the same day with the aim of sparking discussion around an issue of global importance.” The theme for 2009 is Climate Change, the same theme as Earth Science Week in the U.S. Nearly 10,000 bloggers are participating from 150 countries.
The predicted impacts of climate change have been well described as particularly severe in the Southwestern US, with warmer temperatures, more droughts, and more episodic rainfall. For many, this still seems to be something in the far off future. But I just saw a sobering article in the journal Science that caught my attention.
Sustained CO2 levels over 400 ppm during the Miocene period about 20 million years ago, are associated with sea levels 25-40 m (80-130 ft) higher than today.
Jonathan Overpeck ("Peck"), co-director of the Univ. of Arizona's Institute for Earth and the Environment, is one of the co-authors of the 2007 IPCC study that won the Nobel Prize. He is quoted saying, "If anyone still doubts the link between CO2 and climate, they should read this paper."
The article says the study authors predict we will pass the 400 ppm level within a decade. In the Miocene, that level occurred with temperatures about 3-6C (5-11F) higher than today.
An article on BBC News, notes that the International Energy Agency expect greenhouse gases peaking at 510 ppm equivalent before stabilizing at 450 ppm. Peck however, warns that "We don't know where the critical CO2 or temperature threshold is beyond which ice sheet collapse is inevitable."
So, for all of us desert rats waiting for California to fall into the sea along the San Andreas fault, perhaps a more realistic scenario is the Gulf of California expanding northward into the state as sea level rises. Beach front property either way.