National Climate Assessment shows extreme precipitation has increased most in the Northeast

The threats from human-driven climate change detailed in the Fifth National Climate Assessment, released last week, are numerous. But in the Northeast, one stands out: increasingly intense rain and snow.

Extreme precipitation events have increased by about 60% in the Northeast since the 1950s. Intense rain and snow is increasing in most of the U.S., but much more in the Northeast than in other regions.

The assessment says the United States is now experiencing a billion-dollar weather or climate disaster every three weeks, on average. (In the 1980s, the country experienced one of those every four months). Severe storms, flooding, and winter storms make up many of those disasters.

Erin Lane, a scientist with the USDA’s Northeast Climate Hub, was an author of the National Climate Assessment. She says the number of days with more than two inches of rain has increased about 40%.

“The number of days with more than three inches of rain is increasing even more and four inches of rain is increasing even more,” she said. “We looked at the number of days with more than five inches of rain and that has doubled in the last 64 years.”

Lane says as threats are increasing, the efforts to adapt to and mitigate the effects of climate change are also intensifying.

“Those events are motivating action,” she said, noting that most states in the region have plans in place to adapt to and mitigate climate change.

Flooding and insurance 

Despite the adoption of plans, adequate funding for climate adaptation and resilience is a challenge for the Northeast, the assessment says. Private funding has been focused on large businesses and institutions.

“Their focus remains on protecting corporate investments and limiting potential liability, not the equitable distribution of climate mitigation and adaptation funds,” the assessment says.

Federal and state funding has been more available to communities that may face higher burdens from climate change, including historically marginalized and low-income communities.

The authors say property insurance is an important way for individual residents and small businesses to financially protect themselves from the impacts of climate change and the increasingly frequent disasters.

Mark Bove, one of the authors on the National Climate Assessment and a meteorologist who works in the insurance industry, said insurance is “financial resiliency to natural disasters.”

“We're going to see levels of rainfall and flash flooding that in many respects are unprecedented across the region, and we’ve already seen that with the Vermont floods, with flooding earlier this year in Brooklyn,” Bove said. “So this isn’t something for the future. We’re already seeing this in the data today.”

Most homeowners in the U.S. don’t have flood insurance. About 12% to 14% of flood damage is insured by the National Flood Insurance Program, which is run by the federal government.

Only one county in New Hampshire – Rockingham – has more than a 5% flood insurance take-up rate, and most counties have less than a 1% take-up rate. Those rates are both lower than the average in the Northeast – 6.5% along the coast and 1.3% inland.

Bove says there are two main barriers to a wider adoption of flood insurance. One is that many people assume they have no flood risk because their mortgage company does not require insurance. But as the threat of flooding intensifies with climate change, the risks to homes are intensifying, too.

The second challenge is that flood insurance can be expensive.

“We need to figure out ways to make this more affordable, especially for Indigenous and overburdened communities that might not have the financial means to obtain this insurance by themselves,” he said.

Generally, people who live near bodies of water, whose properties repeatedly flood, pay more for their flood insurance. And part of the problem, Bove said, is that the pool of people buying insurance doesn’t include those with smaller flood risks, who may have less repeated expensive damage but still need protection.

“We have built, over time, in our society, in areas that arguably we shouldn’t have built in. We built in flood plains, we built right along the coast,” Bove said. “Now that we’re starting to truly understand the risk and frequency and severity of floods, the price is going to be high in those areas.”

He said insurance is helpful – but to solve the challenge of expensive flood risks, broader partnership is necessary.

New Hampshire’s climate planning 

The certainty with which scientists are able to connect extreme weather events with human-caused climate change is increasing, and that’s shown in the new National Climate Assessment, said Mary Stampone, New Hampshire’s state climatologist and a professor at the University of New Hampshire.

“The greenhouse gas emissions that we've put up into the atmosphere are directly related to some of these increases in extreme weather, like precipitation and heat and drought intensity,” she said. “Being able to make that link between climate change and the severe weather that impacts us so greatly here in the Northeast is a really, really important finding.”

The National Climate Assessment is the “definitive document,” Stampone said, that summarizes the best up-to-date climate science and details how humans are influencing it and how it is influencing humans. The updated document reinforces what scientists have been saying for years.

“Climate change is happening now. We are already experiencing the impacts of climate change. And we have the resources to address it. We're already addressing it to a certain extent, but we need to do more, faster,” she said.

In New Hampshire, the state is revising its climate action plan, which is from 2009. But coming out of that process, adopting similar climate laws as some of our neighbors – Maine, for instance – is something Stampone wants to see.

“We need to do more as a state,” she said.