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In the coming decades, the Boston area is likely to see more intense storms, more hot days, and rising sea levels, a new report from scientists at the University of Massachusetts Boston found.
Specifically, by the end of the century under the worst circumstances, the area in and around Boston could see almost 10 degrees of temperature increase as compared to 2000, coupled with the potential for more than 10 feet of sea rise.
The report explores the impacts of climate change on 101 municipalities in the Boston area, and was published by the Greater Boston Research Advisory Group. Diving into a number of topics, including storms and precipitation, temperature changes, and sea level rise, the report echoes the results of other recent climate change reports, such as studies from the United Nations’ Intergovernmental Panel on Climate Change and the National Oceanic Atmospheric Administration, according to the Boston Globe.
Instead of looking at the world as a whole, however, this report focuses on what will happen to one specific region if climate change is not staunched.
“To think we’ve caused this much change in our climate is astounding,” Paul Kirshen, a professor of climate adaptation at UMass-Boston, and an author of the report, told the Globe. “We’ve already done a hell of a lot of damage, and this report emphasizes the need to get to net-zero emissions.”
So just what could happen to Boston if global emissions don’t fall substantially?
If emissions stay in the highest scenario, the region’s predicted number of days with temperatures over 90 degrees Fahrenheit could rise to as many as 80 days a year, up from eight to 10 from the baseline years (1986-2015). If global emissions fall substantially, the overall increase in temperature could be held to just 3 degrees by 2100, and only on average about 20 days over 90 degrees a year.
The United Nations estimates global emissions are on track to increase by 14% by the end of the decade, so more hot days may be in the future for Massachusetts residents.
Such a large increase in number of hot days poses risks to public health, the study found. Boston’s heat-induced mortality rate will likely increase in coming decades — as much as tripling by 2050. These effects will likely hit marginalized communities the hardest, including those living in urban heat islands — with the report specifically highlighting East Boston, Lower Roxbury, Somerville, and Chelsea/Everett.
“Air quality hazards and respiratory disease, adverse birth outcomes, and transmission of vector-borne diseases are also likely to increase due to temperature changes,” the report reads.
Beyond affecting people themselves, increases in temperature have implications for some of the region’s signature industries, including cranberries and maple syrup, and the catch of lobster and shellfish.
“Under global warming, the waters south of Cape Cod may become too warm to support a lobster population. Warmer waters also promote shell diseases, parasites, and algal blooms that can damage important marine ecosystems and advance instability of coastal economic sectors,” reads the report
With increases in temperature also come increases in sea level. If emissions are reduced substantially, sea level increase might be held at as little as 1 foot over the 21st century, the report said.
However, in Boston Harbor, the relative sea level is likely to rise about 3.4 feet by 2100. Another factor that influences sea level is how much melting of the ice covering Antarctica and Greenland occurs in the next decades, which could raise sea levels by as much as 10.5 feet.
Melting glaciers will affect the Northeast disproportionately, the authors wrote.
“Melting land ice causes changes in Earth’s gravity and rotation that impact regional patterns of sea level rise,” they wrote. “When ice is lost from the West Antarctic Ice Sheet, these processes amplify the resulting sea level rise in Boston by about 25 percent, relative to the global average.”
Though the increase in sea level may not be noticeable for some on a day-to-day basis, daily flooding may have more of an impact. The report found that Boston is likely to have nuisance flooding, when the local flood threshold is exceeded for at least an hour a day, for about half of the year by 2050, compared to about 15 days a year now.
Once-in-a-decade floods are also going to become more common — even with reduced emissions, by 2050 they are likely to occur every year.
Groundwater supplies, where drinking water is pulled from, are projected to decline by 18% due to less snow in the winters, a longer spring, and increased demand for water due to higher temperatures.
“This is absolutely concerning,” Jayne Knott, a research associate at the UMass-Boston School for the Environment and another author of the report, told the Globe. “We depend on groundwater for our drinking water.”
Both river flooding rates and precipitation levels stand to rise in the coming decades. Precipitation levels stand to increase by 10-20% by 2050 and 20-30% by 2100, and with sharp cuts in pollution levels, major river flooding could be kept to a 15% increase.
While storms in the Northeast are highly variable, the authors wrote, there are some predictions about how storms will treat the region in decades to come. Specifically, tropical storms will likely happen less often, but of the storms that do happen, more will be stronger. Extratropical storms on the other hand will decrease in overall frequency, and less of the precipitation they bring will be snow.
As the planet warms, the amount of water vapor in the air increases, which will likely lead to more intense precipitation from storms.
This report is similar to a study the Greater Boston Research Advisory Group published six years ago, and while many of the predictions remained the same, the confidence in the projections has risen.
“We don’t consider these to be conservative estimates any longer,” Ellen Douglas, a professor of hydrology and associate dean at the UMass-Boston School for the Environment, and another author of the report, told the Globe. “These are what we now expect to see.”
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