The impacts of climate change are not just a future threat—they’re already being felt in every region of the United States.
That’s the big takeaway from the National Climate Assessment (NCA), the most comprehensive assessment of U.S. climate impacts to date. The report finds that America has already warmed by an average of 1.6 degrees F since 1895, with most of this warming happening since about 1970. Without efforts to significantly reduce greenhouse gas emissions, the country could see up to 10 degrees F of warming by 2100.
Here’s a look at some of the impacts communities across the United States are already experiencing—as well as steps we can take at the local, state, and federal levels to rein in future warming.
A Regional Look
The assessment shows that while the entire country is and will continue to change in a warmer world, the impacts vary considerably by region. For example:
Between 1958 and 2010, the region saw more than a 70 percent increase in the amount of precipitation falling during very heavy events. The NCA projects that global sea level will rise 1-4 feet by 2100, and the Northeast is expected to exceed the global average due to local factors like sinking land. A 3-foot rise would place up to 2.3 million people at risk in the mid-Atlantic part of the region alone.
Southeast and Caribbean
The Southeast already sees roughly 45,000 wildfires each year—rising temperatures will increase the frequency, intensity, and size. Plus, higher sea levels are accelerating saltwater intrusion into freshwater supplies. Officials in Hallandale Beach, Fla., for example, have already abandoned six of their eight drinking wells. And in the Caribbean, drought is one of the most frequent hazards of climate that is causing economic losses.
Average annual maximum ice cover in the Great Lakes over the last 10 years was more than 20 percent lower than during the 1970s, leaving shores vulnerable to erosion and flooding. One study mentioned in the NCA report projects that Chicago alone could see up to 2,217 heat-related deaths per year by 2081-2100.
The Northern Plains have already experienced more frequent and intense rainfall events that have increased erosion and nutrient runoff. In 2011, parts of Texas and Oklahoma experienced more than 100 days hotter than 100 degrees F, contributing to each state experiencing their hottest summer on record since 1895. This heat contributed to drought that caused more than $10 billion in agricultural losses alone.
The period since 1950 has been hotter than any other period in at least 600 years. Wildfires will likely worsen in warmer conditions, with models projecting a doubling of burned area in the southern Rockies and up to 74 percent more fires in California.
Under one emissions scenario, the annual probability of more than 2 million acres being burned in the region would increase from 1 in 20 to 1 in 2 by the 2080s. By that time, suitable habitat for a number of trout species in the interior Western United States is projected to decline by nearly 50 percent compared to the last 20 years of the 20th century.
Alaska and the Arctic
Alaska has warmed more than twice as fast as the rest of the country over the past 60 years. Late summer sea ice in the Arctic has declined by about half since 1979, and the seven lowest September ice minimums have all occurred in the last seven years.
Hawaii and U.S.-Affiliated Pacific
Even with substantial emissions reductions, coral reefs could lose as much as 40 percent of their fish. Reefs provide an estimated $385 million in goods and services annually to Hawaii, and could be threatened by impacts like bleaching and ocean acidification. The Pacific Island region faces threats to its economically important tuna fishery.
Climate Action at the Local Level
The NCA report makes it clear that local communities are truly at the frontlines of climate change—with vulnerabilities varying by location. However, many of these communities are also at the frontlines of climate action.
More than 1,000 municipalities across the country have signed onto the U.S. Conference of Mayors Climate Protection Agreement, a commitment to reduce emissions locally and push for greater action at the state and federal levels. Many others are pursuing additional initiatives—such as in Southeast Florida, where four bipartisan counties established a Compact outlining more than 100 action items to reduce emissions and adapt to climate impacts.
Many states, too, are pursuing climate adaptation initiatives. The NCA report states that as of 2013, 15 states had completed climate adaptation plans, with 11 more in the process of developing or recommending strategies.
Climate Action at the Federal Level
These seeds of action are encouraging, but ultimately, they’re not enough. As the report notes, “aggressive and sustained greenhouse gas emissions reductions by the United States and by other nations would be needed” in order to prevent some of the more disastrous, projected impacts.
It’s clear, then, that in addition to local and state action, strong federal action is also needed. Analysis highlights some clear starting points:
Power plants are the most significant source of U.S. greenhouse gas emissions, accounting for nearly one-third of the total. Limiting their pollution, then, is the single-greatest action the administration can take to reduce national emissions. As part of his Climate Action Plan, President Obama directed the U.S. Environmental Protection Agency (EPA) to set emissions standards for the country’s existing fleet of power plants. The Agency is set to release these new rules next month. Now is the time for officials to make sure that the standards are ambitious and allow states flexibility in how they comply.
Even significantly reducing emissions from the power sector, though, is not enough to sufficiently rein in warming. The administration should seek to curb emissions from all economic sectors—including reducing methane leakage from natural gas development, improving energy efficiency for homes, businesses and industry, and reducing hydroflourocarbons, potent greenhouse gases found in refrigerants and coolants.
Finally, there is a key opportunity for the United States to step up internationally. Countries have committed to produce a new, global climate agreement by the end of 2015. As part of that process, each country will develop and put forward its domestic emissions-reduction plan by March 2015. The United States should pursue an ambitious emissions-reduction plan — both to curb climate impacts nationally and to inspire greater action globally.
The National Climate Assessment makes it clear that communities throughout the nation are already experiencing the impacts of climate change. Without intervention, these communities will face risks that grow increasingly dangerous with every degree of warming. As the Obama administration moves forward with the Climate Action Plan, the National Climate Assessment should serve as a powerful reminder of the need for significant, long-term action.