Heat, sewer problems and fewer lobsters: New report details impact of climate change in Boston

Climate change will likely bring more hot weather and heat deaths to the Greater Boston area over the next few decades, along with destroyed septic systems, more rain, fewer lobsters and cranberries, threats to the drinking water and more flooding on Morrissey Boulevard.

None of these findings, from a new UMass Boston report released Wednesday, are surprising. But the report provides an unprecedented level of detail on what to expect as the climate changes over the coming decades. Updated and expanded from the 2016 BRAG report to include 101 cities and towns around Boston, it examines projected changes in temperature, storms, flooding, sea level rise and groundwater.

“This report is part of a consistent body of evidence at local, regional, national and international levels showing the urgency of climate action,” said Sanjay Seth, manager of the City of Boston’s Climate Resilience Program. Seth did not contribute research to the report, but will use it to help guide Boston’s climate adaptation plans. “What residents are already seeing is real, whether it’s warmer summers, whether it’s the storms we’re seeing, whether it’s changes in the weather in general, people really understand that climate change is a problem. critical for them.”

Here are seven takeaways from the report:

It’s hotter. And you will feel it.

The average daily temperature in Suffolk County will increase by about 2.5-3℉ by 2040, even if we stop using fossil fuels today. And it could increase to 9℉ by the end of the century if we carry on business as usual.

“So what?” you could say. “In Massachusetts, the weather can change more than 9℉ in an afternoon.”

And it’s true — average annual temperature increases don’t look like this a big problem, but the extremes are worrisome. At present, the region receives about eight or nine days at over 90℉ each year; by the end of the century it will probably be closer to 60 days, and could be 80 days or more. That’s two months – or more – over 90℉ every year.

Projected changes in extreme temperatures in Massachusetts. (Courtesy of Greater Boston Research Advisory Group)

“When you have three, four or five days of temperatures above 90 or 95, the buildings absorb the heat, the pavement absorbs the heat and doesn’t get cold at night,” said Ellen Douglas, a professor at the School of Science. environment of UMass Boston and one of the main authors of the report. Cooling systems can’t keep up, she says. “We’re just going to experience weather extremes that New England wasn’t built for.”

Traditionally underserved, marginalized and at-risk communities will be the hardest hit, especially people living in urban heat islands with little tree cover. Some cities and towns, like Chelsea, are already experimenting with solutions like white roofs and “cool blocks”.

“People who are already overloaded today are going to face even greater risks in the future,” Seth said, “because heat is one of those things that really affects those who are old, those who are young , those who are homeless or have diseases.”

Social justice is an important part of adapting to climate change, said Paul Kirshen, a professor at UMass Boston’s School for the Environment and one of the report’s lead authors. And this must be explicitly taken into account.

Urban Heat Islands and Environmental Justice Communities in Greater Boston.  (Courtesy of Greater Boston Research Advisory Group)
Urban Heat Islands and Environmental Justice Communities in Greater Boston. (Courtesy of Greater Boston Research Advisory Group)

These extremes can also lead to infrastructure problems, such as spalling concrete and buckling train tracks. More heat will also cause losses in some of the state’s traditional products, like cranberries and maple syrup; warming waters are already affecting the fishing industry, as lobsters and other local fish move north.

There will be fewer hurricanes, but bigger ones.

There will probably be fewer hurricanes in the area! But those that do hit will likely be stronger, as the proportion of Category 4 and 5 storms will increase.

Since warmer air holds more water, hurricanes will also bring more rain on us.

On the upside, there will likely be fewer nor’easters, and those hitting Boston will be less intense and carry less snow.

We will see less snow and heavier rains.

There will be less snow overall, but when it snows, we are more likely to get hit. Extreme precipitation – heavy rain or rapid, heavy snow – has increased in recent decades and will continue to increase.

The report predicts a 10-20% increase in daily rainfall intensity by 2050; 20-30% increase by 2100. Those projections haven’t changed much in recent years, Douglas said. However, the numbers are no longer considered conservative.

Joe Ferry of Rockport runs through the waves to retrieve his car before it was submerged by seawater in January 2018. (Jesse Costa/WBUR)
Joe Ferry of Rockport runs through the waves to retrieve his car before it was submerged by seawater in January 2018. (Jesse Costa/WBUR)

Heavier rains will strain Boston’s stormwater infrastructure, which is designed to handle about 5 inches of rain in 24 hours. We could see more than 6 inches in 24 hours by the end of the century, Kirshen said.

“So all of our stormwater management, which is responsible for preventing streets from flooding, basements from flooding, is no longer designed and is not functional,” he said. declared. “Groups like the Boston Water and Sewer Commission need to figure out how they’re going to handle that extra water. There are ways to do that. It’s expensive, but it can be done.”

Drinking water can become scarce (or salty) in some cities.

Many cities and towns around Boston get water from the Quabbin and other surface reservoirs. But 31 rely solely on local wells for drinking water, and these groundwater supplies will be increasingly stretched as the climate changes.

Groundwater is water stored underground in the “saturated zone” of the soil, usually between 8 and 20 feet below the surface. The top of this zone is called the water table. In Massachusetts, groundwater is “recharged” during storms and spring snowmelt.

But climate change will disrupt this pattern: less snow and more heat means less water seeping deep into the ground. And more intense thunderstorms won’t help: there’s a limit to the amount of rain the ground can absorb at one time.

“It’s kind of a double whammy,” Douglas said. “More rain than we get is happening at such a rapid rate that it can’t seep through. And then the temperature is so much higher than anything that Is the infiltrate evaporates faster. And over time, that means less groundwater available for drinking water and ecosystems.”

Some cities that rely on local wells for drinking water have already seen their systems strained due to climate change and population growth, said Martin Pillsbury, director of environmental planning for the Metropolitan Area Planning Council. “A few towns actually pulled their wells out and connected to the MWRA water system or other water systems to replace those wells because it was getting so difficult,” he said. But it’s not cheap and it’s not an option for all cities.

Coastal areas – up to three miles inland – will see different groundwater issues. Rising seas will push salt water into wells, affecting the quality of drinking water. Rising groundwater could also damage septic tanks and other waste management sites located along the coast.

Sea level rise could be lower than originally forecast.

The new report predicts lower sea level rise for Boston Harbor than the 2016 report: 4.8 feet by 2100 under a high emissions scenario instead of 7.4 feet.

“The difference is due to a better understanding of the phenomenon of sea level rise,” Kirshen said.

Projected sea level rise in the Boston area.  (Courtesy of Greater Boston Research Advisory Group)
Projected sea level rise in the Boston area. (Courtesy of Greater Boston Research Advisory Group)

Kirshen points out, however, that 4.8 feet is the most probable number; we could still see more than 15 feet of sea level rise by the end of the century, depending on how the ice caps melt in Greenland and Antarctica. He also noted that Boston has one of the highest sea level rates in the world, in part because the land is sinking about six inches every hundred years as it continues to adjust. since the last ice age. Thank you very much ice cream makers!

Higher seas will also lead to more “nuisance flooding”.

Despite the lower turn-of-the-century projections, Boston will experience more “nuisance” or flooding at high tide, when the local flood threshold is exceeded for at least an hour. Currently, Boston typically experiences fewer than 15 days of nuisance flooding each year. By 2050, harmful flooding could occur on about half the days each year. That means Morrissey Boulevard could be underwater every other day.

“Half the days! That’s a lot. It means every other day we’re not going to UMass Boston,” Douglas said. “We have crossed a threshold for nuisance flooding.”

Douglas noted that there is a movement to start calling nuisance flooding “disruptive flooding”, due to the severe impacts on traffic and infrastructure.

Floodwater covers Morrissey Boulevard in November 2020. (Matt Stone/MediaNews Group/Boston Herald via Getty Images)
Floodwater covers Morrissey Boulevard in November 2020. (Matt Stone/MediaNews Group/Boston Herald via Getty Images)

Even if things look bleak, it’s still worth trying to reduce emissions.

“It’s really important that we try to achieve net zero emissions by 2050,” Kirshen said. “If we do that, we may only have a foot of sea level rise by the end of the century.”

While a foot of sea level rise is no picnic, it’s much more manageable than 5, 10 or 15 feet, he says. And what we know will determine where we end up in the year 2100.

“What [the report] shows me we have a window to fight climate change,” said Seth, Boston Climate Resilience Program Manager. “We have a window to prepare our cities for the inevitable effects. But there is no world in which we have cities that can thrive if we don’t tackle climate change with a meaningful sense of urgency. »

Teresa H. Sadler