Environment New Hampshire Research and Policy Center
Weather disasters kill or injure hundreds of Americans each year and cause billions of dollars in damage. The risks posed by some types of weather-related disasters will likely increase in a warming world. Scientists have already detected increases in extreme precipitation events and heat waves in the United States, and climate science tells us that global warming will likely lead to further changes in weather extremes.
Since 2007 , federally declared weather-related disasters in the United States have affected counties housing 243 million people – or nearly four out of five Americans. The breadth and severity of weather-related disasters in the United States – coupled with the emerging science on the links between global warming and extreme weather – suggest that the UnitedStates should take urgent action to reduce emissions of global warming pollution and protect communities from the dangers posed by climate change.
Weather-related disasters are common in the United States, affecting people in every part of the country.
• Since 2007, weather-related disasters have been declared in every U.S. state other than South Carolina. During this period, weather-related disasters affected every county in 18 states and the District of Columbia. (Alabama, Arkansas, Connecticut, Delaware, Hawaii, Iowa, Louisiana, Massachusetts, Maryland, Maine, Missouri, North Dakota, New Hampshire, New Jersey, Oklahoma, Rhode Island, Vermont and West Virginia.) (See Figure ES-1.)
• More than 18 million Americans live in counties that have averaged one or more weather-related disasters per year since the beginning of 2007. Eight U.S. counties – five in Oklahoma, two in Nebraska, and one South Dakota – have each experienced 10 or more declared weather-related disasters since the beginning of 2007.
• More than 76 million Americans lived in counties affected by weather-related disasters in 2012. There were at least 11 disasters that each inflicted more than $1 billion in damage, including Hurricane Sandy, whose estimated $65 billion in damages made it the most costly weather disaster since Hurricane Katrina in 2005.
• As of February 2013, 705 counties housing more than 63.5 million people had been designated primary natural disaster areas as a result of drought conditions.
Extreme weather events were responsible for many of 2012’s worst weather-related disasters.
• The contiguous United States experienced its hottest month and hottest year in recorded history in 2012. The U.S. smashed the previous record for warmest year – exceeding the previous record year (1998) by 1 ̊F. The United States experienced its warmest spring, second-warmest summer and fourth-warmest winter in 2012. The nation also posted its warmest single month on record in July 2012.
• Nebraska and Wyoming experienced their driest years on record, while other Plains and Midwestern states experienced drier than normal conditions.
• The U.S. experienced its most widespread drought in more than a half century, as a result of record heat and low rainfall. In July 2012, 56 percent of the nation experienced moderate to extreme drought, according to the National Climatic Data Center, making it the most widespread drought since at least 1956.
• Hurricane Sandy broke or challenged multiple records. It was the largest tropical cyclone in terms of area since modern record-keeping began in 1988, caused the lowest barometric pressure ever recorded along the Northeast U.S. coast, and produced record storm tides in the New York City area.
Some types of extreme weather events have become more common in recent years in the United States and worldwide, while science projects that global warming will likely fuel future changes in extreme weather in the years ahead.
• The United States has experienced an increase in heavy precipitation events, with the rainiest 1 percent of all storms delivering 20 percent more rain on average at the end of the 20th century than at the beginning. The trend toward extreme precipitation is projected to continue, even though higher temperatures and drier summers will likely also increase the risk of drought in between the rainy periods for certain parts of the country.
• The United States has experienced an increase in the number of heat waves over the last half-century. Scientists project that heat waves and unusually hot seasons will likely become more common in a warming world.
• Hurricanes may become more intense and bring greater amounts of rainfall, even though the number of hurricanes may remain the same or decrease.
• Global warming may also make extreme weather events more dangerous. Rising sea level, ecosystem changes, and changes in the form of precipitation could reduce the ability of natural and man-made systems to withstand even “normal” weather events.
The United States should reduce global warming pollution now, and plan for a future in which some types of extreme weather events are more severe and occur more frequently.
• Federal and state governments should adopt and implement caps on global warming pollution capable of reducing emissions by at least 35 percent below 2005 levels by 2020 and by at least 85 percent by 2050. These emission reductions are broadly consistent with what science tells us is necessary to lessen the most costly and devastating consequences of global warming.
• Short of economy-wide caps on global warming pollution, local, state and federal governments should focus on capping and reducing pollution from the largest sources – most notably power plants and the transportation sector. Regional programs such as the Northeast’s Regional Greenhouse Gas Initiative can help to achieve this goal, as can the first-ever federal carbon pollution limits for power plants currently being developed by the U.S. Environmental Protection Agency.
• In order to avoid making the problem worse, decision-makers should reject new carbon-rich fuels such as tar sands, as well as supporting infrastructure projects such as the proposed Keystone XL tar sands pipeline that facilitate the development of these carbon-rich fuels.
• The United States – including federal, state and local governments – should adopt clean energy solutions that reduce our dependence on fossil fuels and reduce global warming pollution. Among the most important steps are:
o Adopting enforceable targets, financial incentives, regulatory changes, and investment strategies that increase the use of renewable energy sources such as wind and solar power.
o Implementing appliance standards, building codes, enforceable efficiency targets for utilities, fuel-efficiency standards for vehicles and other steps to promote energy efficiency.
o Continuing to develop and implement the fuels and technologies of the future – from electric vehicles to energy storage devices to “smart grid” technologies and new renewable sources of energy – through government support of research, development and deployment of those technologies and the adoption of technology-forcing standards where appropriate.
• Federal, state and local officials should take steps to better protect the public from the impact of extreme weather events – steps that save costs compared to suffering the full brunt of these extreme events. Government officials should explicitly factor the potential for global warming-induced changes in extreme weather patterns into the design of public infrastructure, revise policies that encourage construction in areas likely to be at risk of flooding in a warming climate, and continue to support research on the implications of global warming.