For the second year in a row, unprecedented numbers of extreme weather events have occurred across the globe. However, more of 2011’s impacts occurred in the United States. From the drought in Texas to the floods in the Midwest and Northeast, this past year underscored the huge economic costs associated with extreme weather. While specific weather events are not solely caused by climate change, the risks of droughts, floods, extreme precipitation events, and heat waves are already climbing as a result of climate change. This year reminded us of our vulnerability to those events.
The most persistent weather event of 2011 has been the drought in Texas . The 12 month period from September 2010 to August 2011 was the driest on record in Texas, worse than historical Texas droughts that occurred in the 1950s and the 1930s Dust Bowl. The drought was accompanied by extreme heat and very poor conditions for growing crops or raising livestock. Although some much needed rain fell during the fall, drought conditions are ongoing. Total direct losses to crops, livestock, and timber are estimated at $10 billion and will continue to rise until the drought abates.
The historic dryness combined with extreme heat to make 2011 the worst wildfire season ever in Texas. Major wildfires also broke out in New Mexico and Arizona. All three states recorded their largest wildfire ever with Texas losing 3 million acres and over 1,500 homes. Texas State Climatologist John Nielsen-Gammon estimates  that global warming contributed some portion of the excess heat that has made this drought more intense than any drought in the past 120 years.
While Texas was suffering from a lack of rain, other parts of the country were suffering from too much of it. Spring floods affecting the Souris, Missouri and Mississippi rivers inundated parts of the Midwest. Rainfall in the Ohio Valley was 300 percent above normal. Levees were breached along the Missouri and Mississippi rivers drowning farmland and flooding thousands of homes. Many rivers crested at record highs, causing losses in excess of $5 billion.
Flooding was also an issue through large parts of the Northeast, the result of drenching rains from Hurricane Irene. Although wind damage from Irene was not as severe as feared, flood damage was more severe across New Jersey, New York, and Vermont with hundreds of bridges and roads washing out and extensive flooding in many towns. Although Irene only made landfall as a Category 1 hurricane, it was one of the most expensive storms on record in the United States, causing damages in excess of $7 billion.
These events represent only three of the 12 weather disasters estimated to cost more than $1 billion each that struck the United States this year, according to official government estimates.  Overall, these 12 major events set a new record, doubling the previous records from 2009 and 2006. Even excluding the six billion-dollar disasters that were tornado related—where the connection to climate change is still uncertain—the remaining six still set a new record for the most non-tornado related disasters in a single year. This record number of disasters, excluding tornadoes, should remind us of our vulnerability to extreme weather as the risk of such events continues to rise. This increase in risk is directly tied to the continued growth in greenhouse gas emissions above preindustrial levels. There is little sign of a slowdown, as emissions increased by a record amount in 2010 .
The extreme weather of 2011 serves as a reminder of our vulnerabilities and that our failure to adequately limit greenhouse gas emissions comes with a cost. While mitigation and adaptation actions both will be necessary and require resources, not acting exposes us to far greater costs as evidenced by the recent impacts of extreme weather.
Dan Huber is a Science & Policy Fellow at C2ES.