Economist Helps Demonstrate Global Benefits of Keeping Water Clean

A University of Wyoming economist contributed to a new paper that demonstrates why keeping local lakes and other water bodies clean can deliver valuable social benefits both locally and globally.

The paper, which may be found here, was published online Tuesday in the journal Nature Communications. The research was led by University of Minnesota Sea Grant Director John Downing. Stephen Newbold, an assistant professor of economics at UW, is a co-author of the study.

Public do-not-drink orders, damages to fishing activity, lost recreational opportunities, decreased property values and increased likelihood of low birth weight among infants born to mothers exposed to polluted water from lakes with harmful algal blooms are some of the reasons that clean water is important. Many people appreciate these local benefits and want their local lakes and streams to be clean and useable for drinking, fishing, swimming and recreation. But some previous cost-benefit studies found that the costs of protecting local water sources exceed the benefits.

One reason for this, say the authors, is that scientists and economists have previously considered a limited set of local benefits when calculating the benefits of good water quality. Downing and co-authors sought to calculate the potential global benefits.

“Surface water is one of the Earth’s most important resources,” says Downing, who also is a lake scientist at the University of Minnesota-Duluth Large Lakes Observatory. “Our research demonstrates that there is significant local and global value to protecting local water quality.”

The researchers found that keeping water clean can help slow climate change, with a global social value of up to trillions of dollars. Using a Lake Erie case study as an example, the authors also found that the global climate change value of protecting and preventing this Great Lake from algae blooms was 10 times greater than the value of beach use or sport fishing.

Locally, cleaning or keeping a lake or water body free of excess nutrients, including nitrogen and phosphorus, that lead to excessive algal growth — what scientists call eutrophication — is obviously good for people who use or want to access that particular water body. The eutrophication of lakes and estuaries degrades habitat conditions for harvested and non-harvested fish; produces water and airborne toxins harmful to animals and people; and diminishes the recreational use and aesthetic appeal of the affected water bodies.

Globally, protecting local water bodies also is good for reducing the amount of the greenhouse gas methane that is released into the atmosphere from eutrophic surface waters.

“Our study is the first to quantify a potentially important category of impacts that has previously been neglected: the potential long-run economic costs of eutrophication due to emissions of methane — a potent greenhouse gas that contributes to global climate change — produced by eutrophic lakes,” Newbold says.

Methane is a stronger greenhouse gas than carbon dioxide because it has a much higher heat-trapping ability and has about 21 times the global warming potential of carbon dioxide. Less methane in the atmosphere can help slow global warming.

The cost of climate change comes from health care costs, damages to urban infrastructure, agricultural damages, catastrophic storm damage, negative impacts on recreation, forestry, fisheries, energy systems, water systems, construction and coastal infrastructure.

“We calculated the global climate damages from methane emissions from eutrophic lakes and the damages that would be avoided by preventing increased emissions from 2015 to 2050,” Downing says. “If we could hold methane emissions at current levels rather than the expected 20 percent to 100 percent increase by 2050, the value of avoiding the resulting damages could be as much as $24 trillion.”

The authors estimated the costs of global climate change due to eutrophication from 2015 to 2050 to be as much as $81 trillion.

The authors’ analysis shows that local water quality protection has global economic implications. The substantial emissions they documented from lakes and reservoirs and the potential for increased emissions suggest that there is considerable value to be gained by improving water quality in lakes and reservoirs and in preventing further deterioration.

“It’s not possible to avoid all emissions from lakes and reservoirs but, with concerted effort, it may be possible to prevent increased emissions or even reverse it,” Downing says.

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