When the Environmental Protection Agency mandated regulations for the cleanup of Lake Champlain, one concern was whether Vermont could actually meet those standards. Now a new study suggests that the bar the EPA has set may actually be too low, because the lake may be more susceptible to climate change than previously thought.
The new study, conducted by scientists at the University of Vermont and Dartmouth College, looked at how sensitive Lake Champlain is to climate change also how land management policies can be used to help keep the lake clean.
VPR spoke with UVM professor Asim Zia, the lead author of the study, about the results and what they mean for how Vermont approaches its cleanup of the lake.
VPR: We don't know exactly how climate change is going to affect our environment, so how did the model in your study work?
Zia: “There are different scenarios with the climate change. For example under the worst-case climate change scenario, we can see very high [temperature increase] of 4 degrees centigrade by the end of this century…Under the Paris Treaty, we can get probably up to 2.5 to 3 degrees centigrade [increase]. And the best case... we can keep [the increase] under 1.5 degrees centigrade.
“The important thing is that in this study we modeled all of those different ... scenarios, as well as the different land use management policies.
"We simulated about 48 different scenarios to understand a range of different climate and land use scenarios to see whether the lake, especially the Missisquoi Basin, can be cleaned up or not.”
The EPA has said that any increases in the phosphorus loads to the lake due to climate change are likely to be modest. Your study found that is not the case.
“Typically when people think about climate change, they say that climate change is going to have a distant effect on polar bears or people living in Bangladesh … This study demonstrates that the effects are real and are in our neighborhood.
“Lake Champlain is an important resource, a vital resource for all of Vermonters, New Yorkers and the people of Quebec. But their role in setting up water quality standards has been marginal so far. They have not been the main focus of the models that were used by the EPA to develop those standards.
“They [the EPA] basically just used one climate scenario … and didn't explore all the ranges of the scenarios that we did. I think that was one of the weaknesses in their models.
“I don't want to demean the efforts that the EPA has put in the current [guidelines], [but] we need to do more to keep the lake clean.”
Does the study make any recommendations about what the state of Vermont could or should do?
“Yes. I think the major recommendation is we need, not just [Vermont] but also at the federal level, to reevaluate the TMDL [total maximum daily load] process.
“Our major goal was to build our adaptive capacity of the region. It's not just a one-shot study; we want to make this model available to the policymakers not only in Vermont, but also for the rest of the country.
“We need to go back to the drawing board and think very clearly whether we want to have a medium to long-term strategy to keep the lake resilient against these threats from climate change.”
Does your study take into account what some of these improvements to protect lake could cost?
“NSF [The National Science Foundation] has given us another five years grant and we want to get deeper into the cost. So we're going to look into details, like, 'Which is the most cost-effective path to mitigate this phosphorus pollution in the lake?'
“Our preliminary assessment is that there is not going to be one single solution. It will have to be done by all the sectors. If we're going to ratchet up the regulations in terms of the pollution control, we will need to figure out a more comprehensive [and] holistic approach from the land use land management perspective.
“So what we need to really think deeply about is, 'What type of development paradigm do we want to have for urbanization as well as for the agricultural expansion?'"
In a statement, the EPA responded to the findings of the study saying it “welcomes the important contribution” that the paper made to the understand of how climate change and land use effect water quality in Missisquoi Bay.
However, the EPA stated that the paper mischaracterizes the “considerations of climate change in the Lake Champlain TMDLs” and that the EPA also looked at four global circulation models “…rather than just one, as stated in the Conclusion section of the paper.”
According to the release, the EPA did only consider one emissions scenario, but it was the “most pessimistic” scenario available during their analysis.
The EPA also expressed concern that the University of Vermont’s press release about the study spoke more broadly about Lake Champlain when the study was focused on Missisquoi Bay.