30 July - 5 August 2012 - orsam

U.S. Drought and Climate Change: Science Points to Link
The drought that‘s turned most of the United States into a dessicated hotbox may be a symptom of
climate change, a brutal blowback from carbon pollution.
Climate scientists, who prefer to speak in terms of probabilities and trends rather than single events,
are reluctant to point fingers at any one cause — but signs point to human influence making a natural
dry spell unnaturally severe.
―In any single event, it‘s hard to really know if you‘re just seeing a natural variation or climate
change,‖ cautioned climatologist Chris Funk of the University of California, Santa Barbara. With that
caveat, Funk said when asked if human activity exacerbated the drought, ―Tentatively, the answer is
yes. To some extent, it is.‖
Public sentiment has already linked the drought, which has turned much of the Great Plains and
Midwest into disaster areas, wrecking crops and driving food prices dangerously upwards, to
unnatural climate fluctuation. Belief in climate change is now at an all-time U.S. high, and while
explaining the causes of any large weather pattern is always difficult, enough is known about climate
to make some educated guesses.
Funk‘s specialty is the dynamics of sea surface temperatures in the Indian Ocean and western Pacific
Ocean. Over the last century, and in particular the last two decades, these rose by an average of 1.25
degrees Fahrenheit. Ocean temperature trends can be tricky to interpret, but there‘s little scientific
disagreement about Indian Ocean warming: It‘s almost certainly man-made, a result of greenhouse
gases trapping heat in Earth‘s atmosphere.
'When these patterns do materialize, they're materializing in a warming climate.'
The consequences are significant. Heated air holds extra water, supercharging monsoon systems and
producing events like 2010′s Pakistan floods. Water vapor is also a greenhouse gas itself, trapping
heat and creating a feedback loop of local warming.
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