Climate Change Impacts in the United States
As the impacts of climate change emerge, Americans are coping with the consequences, and many are taking steps to prepare for further impacts. Each region of the US has been affected differently, and each will experience a different combination of impacts in the future.
Worsening drought and wildfire conditions are among the most conspicuous and costly impacts presently affecting the West, where a majority of Latinos live. Extended drought has been especially costly for California’s agricultural sector, where the drought in the Central Valley alone has resulted in the loss of thousands of jobs, with significant effects on Hispanic workers, who make up more than two-thirds of California’s agricultural labor force.
As climate has changed, fire seasons in the US have been getting longer; the average area burned annually has doubled relative to what it was three decades ago. The 2015 fire season, one of the worst on record, was consistent with that trend, with more than 9.3 million acres burned by October 16.
The dramatic increase in the number of large fires has increased the annual acreage burned and escalated fire suppression costs. Wildfires in Arizona, New Mexico, Colorado, and California all increased in size and—in many cases—broke records in acreage burned.
As climate has changed, fire seasons in the US have been getting longer; the average area burned annually has doubled relative to what it was three decades ago. The 2015 fire season, one of the worst on record, was consistent with that trend, with more than 9.3 million acres burned by October 16. During only four fire seasons between 1960 and 2015 has total acreage burned exceeded 9 million acres and all have occurred during the last decade: 2006, 2007, 2012 and 2015.
The dramatic increase in the number of large fires has increased the annual acreage burned and escalated fire suppression costs. In 2011, the Wallow Fire (538,049 acres) was the largest wildfire ever recorded in Arizona; also in 2011, the Las Conchas Fire (over 150,000 acres) was the largest ever in New Mexico. The following year, in 2012, California experienced its second largest fire on record: the Rush Fire that burned nearly 271,911 acres. And in 2013 the Rim Fire burned 257,314 acres, becoming the third-largest wildfire in California history. That same year, Colorado experienced its second large fire, the West Fork Fire Complex (110,405 acres).
Short-term droughts are expected to intensify in most of the US, while longer-term droughts are predicted to worsen in large areas of the Southwest, southern Great Plains, and Southeast, according to the study Climate Change Impacts in the United States.
California is experiencing one of its worst droughts on record—one that already has stretched over four years. This time period includesthe warmest year (2014) and driest year (2013) on record. Recent research attributes the drought in part to global warming, indicating that warming has significantly raised the chances of extreme droughts in California.
In the Southwest region of the US, future droughts will likely be substantially hotter, with serious implications for water supplies.
Fed by the Colorado River, Lake Mead is the source of water for over 30 million people in the southwestern US. But its water level has dropped dramatically as the Southwest experiences a long-term drought. The white band along the rock face shows the difference between Lake Mead’s capacity and its historical highwater level. Since then, water levels have declined further, reaching record low levels in mid-2015.
As climate changes, there are shifts in US weather extremes. The intensity and duration of North Atlantic hurricanes have increased since the early 1980s.
In October 2012, Hurricane Sandy made landfall in New Jersey, fueled in part by unusually warm ocean waters along the US east coast. Sandy’s unusual track before landfall was influenced by a jet stream pattern that may have been substantially influenced by Arctic warming. Sandy was the largest tropical storm on record since 1988, and produced a record storm surge in several locations. Total damages were estimated at $67 billion.
Flash and urban floods are tied to heavy precipitation events, while coastal floods are related to sea level rise. The results of these coastal floods is an increase in storm surge height, and inland impacts are expected to increase moving forward, according to the study Climate Change Impacts in the United States.
Floods are among the most common and costly weather-related disasters in the US, with average damages of nearly $8 billion per year during the last 30 years (excluding flooding from coastal storm surges). Heavy precipitation events have increased in the US, a trend that is projected to continue in all regions of the country.
From Sept. 9 to 16, 2013, record-breaking precipitation fell along the Colorado Front Range, particularly in and around the city of Boulder. The city received over nine inches of rain on Sept. 12 alone, breaking the city’s 24-hour precipitation record, along with its monthly and annual precipitation records.
Over the last century, sea level rose by eight inches And it is expected to rise at least another 1-4 feet this century.
The combination of sea level rise and more energetic coastal storms threatens coastal groundwater supplies and wetlands. Also threatened are coastal communities and infrastructure including water supplies, energy, and transportation facilities.
As a result of rising sea level alone, Florida projected property damage is up to $14.8 billion by 2030 and up to $23.3 billion by 2050, according to the Risky Business Projects report Come Heat and High Water: Climate Risk in the Southeastern U.S. and Texas.