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Connecting the dots between climate change and extreme weather

By: Dr. Jeff Masters, 3:15 PM GMT on May 04, 2012

Connecting the dots between human-caused climate change and extreme weather events is fraught with difficulty and uncertainty. One the one hand, the underlying physics is clear--the huge amounts of heat-trapping gases like carbon dioxide humans have pumped into the atmosphere must be already causing significant changes to the weather. But the weather has huge natural variations on its own, without climate change. So, communicators of the links between climate change and extreme weather need to emphasize how climate change shifts the odds. We've loaded the dice towards some types of extreme weather events, by heating the atmosphere to add more heat and moisture. This can bring more extreme weather events like heat waves, heavy downpours, and intense droughts. What's more, the added heat and moisture can change atmospheric circulation patterns, causing meanders in the jet stream capable of bringing longer-lasting periods of extreme weather. As I wrote in my post this January, Where is the climate headed?, "The natural weather rhythms I've grown to used to during my 30 years as a meteorologist have become significantly disrupted over the past few years. Many of Earth's major atmospheric circulation patterns have seen significant shifts and unprecedented behavior; new patterns that were unknown have emerged, and extreme weather events were incredibly intense and numerous during 2010 - 2011. It boggles my mind that in 2011, the U.S. saw 14 - 17 billion-dollar weather disasters, three of which matched or exceeded some of the most iconic and destructive weather events in U.S. history."

Figure 1. Women who work on a tea farm in Assam, India hold up a dot in honor of Climate Impacts Day (May 5, 2012), to urge people to connect the dots between climate change and the threat to their livelihood. Chai is one of the most consumed beverages in India, but a prolonged dry spell and extreme heat has affected tea plantations in Assam and Bengal with production dropping by 60% as compared to the same period in 2011. Image credit: 350.org.

May 5: Climate Impacts Day
On Saturday, May 5 (Cinco de Mayo!), the activist group 350.org, founded by Bill McKibben, is launching a new effort to "connect the dots between climate change and extreme weather." They've declared May 5 Climate Impacts Day, and have coordinated an impressive global effort of nearly 1,000 events in 100 countries to draw attention to the links between climate change and extreme weather. Their new climatedots.org website aims to get people involved to "protest, educate, document and volunteer along with thousands of people around the world to support the communities on the front lines of the climate crisis." Some of the events planned for Saturday: firefighters in New Mexico will hold posters with dots in a forest ravaged by wildfires; divers in the Marshall Islands take a dot underwater to their dying coral reefs; climbers on glaciers in the Alps, Andes, and Sierras will unfurl dots on melting glaciers with the simple message: "Melting"; villagers in Northeastern Kenya will create dots to show how ongoing drought is killing their crops; in San Francisco, California, aerial artist Daniel Dancer and the Center for Biological Diversity will work with hundreds of people to form a giant, moving blue dot to represent the threat of sea level rise and ocean acidification; and city-dwellers in Rio de Janeiro hold dots where mudslides from unusually heavy rains wiped out part of their neighborhood. I think its a great way to draw attention to the links between climate change and extreme weather, since the mainstream media coverage of climate change has been almost nil the past few years. A report by Media Matters for America found out that nightly news coverage about climate change on the major networks decreased 72% between 2009 and 2011. On the Sunday shows, 97% of the stories mentioning climate change were about politics in Washington D.C. or on the campaign trail, not about extreme weather or recent scientific reports. You can check out what Climate Impacts Day events may be happening in your area at the climatedots.org website.

Figure 2. Front Street Bridge on the Susquehanna River in Vestal, NY, immediately following the flood of September 8, 2011. Image credit: USGS, New York. In my post, Tropical Storm Lee's flood in Binghamton: was global warming the final straw? I argue that during September 8, 2011 flood, the Susquehanna River rose twenty feet in 24 hours and topped the flood walls in Binghamton by 8.5 inches, so just a 6% reduction in the flood height would have led to no overtopping of the flood walls and a huge decrease in damage. Extra moisture in the air due to global warming could have easily contributed this 6% of extra flood height.

Also of interest
Anti-coal activists, led by climate scientist Dr. James Hansen of NASA, are acting on Saturday to block Warren Buffett's coal trains in British Columbia from delivering coal to Pacific ports for shipment overseas. Dave Roberts of Grist explains how this may be an effective strategy to reduce coal use, in his post, "Fighting coal export terminals: It matters".

The creator of wunderground's new Climate Change Center, atmospheric scientist Angela Fritz, has a blog post on Friday's unveiling of the new Heartland Institute billboards linking mass murderers like Charles Manson and Osama Bin Laden to belief in global warming. In Heartland's description of the billboard campaign, they say, "The people who still believe in man-made global warming are mostly on the radical fringe of society. This is why the most prominent advocates of global warming aren't scientists. They are murderers, tyrants, and madmen." The Heartland Institute neglected to mention that the Pope and the Dalai Lama are prominent advocates of addressing the dangers of human-caused climate change.

Jeff Masters

Extreme Weather Climate Change

The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.