Experts are no longer questioning a link between global warming and the frequency and intensity of our current weather extremes:
In 2004, Liza Sloan, a professor of Earth science at the University of California at Santa Cruz, published a study in the journal Geophysical Research titled “Disappearing Arctic sea ice reduces available water in the American west.” In that article, which she wrote with graduate student Jacob Sewall, Sloan predicted that as Arctic sea ice melted because of accelerating climate change, the American west would become increasingly susceptible to the kind of lengthy droughts and heat waves we’re seeing right now in the summer of 2013.
The same kind of droughts and heat waves that caused the fire that killed 19 Granite Mountain Hotshots.
The logic behind their study was simple. When cool sea ice melts, it makes it easier for warm air to rise out of the ocean over the polar regions and funnel up into the atmosphere. Sewall explained the process to the UC Santa Cruz newspaper at the time:
“The sea ice acts like a lid over the ocean surface during the winter, blocking the transfer of heat from the ocean to the atmosphere… Where the sea ice is reduced, heat transfer from the ocean warms the atmosphere, resulting in a rising column of relatively warm air.”
As the two scientists discovered, that change in normal arctic air patterns in turn pulls normal winter storm systems from the American west up north over Canada, significantly reducing annual rainfall throughout the American west.
When Sloan and Sewall ran their data through one of the National Center for Atmospheric Research’s modeling computers, they found that such a shift would lead to as much as a 30 percent or a 17 percent drop in precipitation by 2050 in some parts of the Western United States. In other words: drought.
A new and improved version of Sloan and Sewall’s study came out in 2005, concluding pretty much the same thing: that melting Arctic sea ice would lead to drastic reductions in rainfall in the American West.
No one listened to Jacob Sewall and Lisa Sloan when they published their study almost a decade ago, but we should have. Their predictions are coming true. The Western U.S. is currently in the middle of a record busting heat-wave and drought.
When contacted by ThinkProgress to comment on the current climate crisis west of the Mississippi, Jacob Sewall said that current conditions match up with or are even worse than what he and Sloan predicted almost a decade ago. Arctic sea ice reached its projected concentration in 2011, a shocking fact when you consider that those predictions were for the year 2050. And precipitation levels in places like California are 15 percent lower than what Sloan and Sewell originally estimated, that doesn’t mean their research was wrong.
As Sewall told ThinkProgress, ““I think the hypothesis from 2004 and 2005 is being borne out by current changes. The only real difference is that reality is moving faster than we thought it would almost a decade ago.”
That’s right - faster. Terrifying stuff.
