Changes in the climate could “outpace” efforts to combat, through land use management, the proliferation of toxic blue-green algae in Lake Champlain, the paper states.
In particular, global climate change is expected to bring more precipitation to Northeast states, according to the paper. The increased rainfall is likely to create more runoff of agricultural waste flowing into Lake Champlain, encouraging the growth of blue-green algae, the paper states.
The uptick in dissolved nutrients in Lake Champlain’s water could be exacerbated by warming of the water as the Earth’s climate warms, the UVM researchers say.
These effects, depending on their severity, could dramatically reduce the land use options for keeping phosphorus pollution in the lake at levels low enough to avert blue-green algae outbreaks, the researchers say.
The model UVM researchers developed to arrive at these results is one policymakers could benefit from in the future, said one of the paper’s authors, Arne Bomblies, an assistant professor at UVM’s Department of Civil and Environmental Engineering.
It’s the first model to incorporate social trends, hydrodynamics, phosphorus transport, government policy and numerous other variables, with an output pertaining strictly to water quality, Bomblies said.
“Previously the assumption has been, or most of the work in hydrology has focused on, a pristine environment,” he said. This model assumes a changing landscape under the influence of human activity, he said.
The U.S. Environmental Protection Agency this year approved limits on the amount of phosphorus Vermonters may introduce into Lake Champlain, primarily from dairy farms and runoff. That set of pollution limits, called a total maximum daily load, may rest on incorrect assumptions about Vermont’s future weather patterns, by failing to adequately account for the effects of global climate change, the UVM researchers said.
The EPA’s own research suggested that over the coming decades, global climate change and its effects will introduce relatively little new phosphorus (around 15 percent, the TMDL estimates) into Lake Champlain.
This might underestimate the true amount, the UVM scientists’ research suggests.
By considering a wider array of possible climate scenarios, the UVM researchers uncovered probable scenarios where the effects of weather patterns on phosphorus pollution would overwhelm efforts to stem that pollution through land use decisions.
Scientists from the EPA took issue with the UVM researchers’ findings.
The agency actually considered numerous emissions scenarios, as the UVM paper’s authors did, and modeled the TMDL numbers around the most pessimistic (or highest-emission) scenario, EPA officials said in a statement.
The EPA also faulted the UVM researchers for extending to the entire Lake Champlain findings that pertain mostly to Missisquoi Bay alone. The bay is shallow and mostly enclosed and has significant phosphorus in its sediment — conditions not representative of the lake as a whole, EPA scientists said.
EPA officials also said the paper underscores a need to approach the problem of phosphorus pollution in Lake Champlain with a willingness to adapt to new information. This need led the EPA to write Lake Champlain’s pollution limits in a way that each new stage of implementation builds upon results and information from previous stages, officials said.
“EPA particularly appreciates the complexity inherent in the systems approach taken by the (UVM) team and the efforts to connect the research to real-world environmental challenges,” EPA representatives said in a statement. “Efforts like this can only improve the quality of policy discussions regarding Missisquoi Bay over time.”
The UVM paper appears in the Nov. 17 issue of Environmental Research Letters.
Research for the article was funded in part by the National Science Foundation.
Besides Bomblies, the authors include Asim Zia, Andrew Schroth, Christopher Koliba, Peter Isles, Yushiou Tsai, Ibrahim Mohammed, Gabriela Bucini, Patrick Clemins, Scott Turnbull, Morgan Rodgers, Ahmed Hamed, Brian Beckage, Carol Adair, Gillian Galford, Donna Rizzo and Judith VanHouten, all of various departments at UVM.
Researchers came from departments at UVM including Community Development & Applied Economics, Computer Science, Civil and Environmental Engineering, Geology and Biology.
Another researcher, Jonathan Winter, hailed from Dartmouth College.
