AGU Meeting: Current SW Drought Could Well Be Megadrought Like 1200 - 1300s

[hatrack]

EDIT

“The current drought could be classified as a megadrought — 13 years running,” paleoclimatologist Edward Cook, director of the Tree Ring Laboratory at Columbia University’s Lamont-Doherty Earth Observatory in Palisades, N.Y., said at an AGU presentation Wednesday night. “There’s no indication it’ll be getting any better in the near term.” But the long period of drought the West is currently experiencing may not be a product of human-caused climate change, and could be natural, he said.

“It’s tempting to blame radiative forcing of climate as the cause of megadrought,” Cook said. “That would be premature. Why? There’s a lot of variability in the system that still can’t be separated cleanly from CO2 forcing on climate. Natural variability still has a tremendous impact on the climate system.”

Tree ring data show that decades-long droughts have occurred before humans started emitting greenhouse gases that fuel climate change. Long-lasting drought events have been tied to fluctuations in ocean conditions, which can alter large-scale weather patterns. For example, when the tropical Pacific Ocean is cooler than average, but the Atlantic Ocean is unusually mild — as has been the case during the past several years — there is a higher risk of drought in parts of the West and Central U.S.

The area of the West that was affected by severe drought in the Medieval period was much higher and much longer than the current drought, tree ring data show.

EDIT

http://www.climatecentral.org/news/is-the-wests-dry-spell-really-a-megadrought-16824

[gtar100]

1. That climate change is not always caused by human emissions of greenhouse gasses is, well... duh!

But adding into the mix the atrocious amounts of pollutants into the air that we do every day (with very little effort at stopping) is a recipe for disaster. I don't think Cook should be isolating historical trends from the unprecedented pollution we are pouring into our atmosphere and conclude that humans are outside the equation of current conditions. Though natural cycles are essential to understand, we have an urgent situation at hand, the causes of which are our own doing, and I worry about fodder for the denialists.