The transportation sector is the largest emitter of carbon dioxide in Maine. All that carbon is increasing the ocean's acidity, threatening our environment and Mainers who earn their livelihood on the water. Credit: Lindsay Putnam

When National Highway Traffic Safety Administration Secretary Elaine Chao and acting Environmental Protection Administration Secretary Andrew Wheeler announced their agencies’ rollback of federal clean car standards in August, they pledged to “ Make Cars Great Again.” In doing so, they have threatened our air, water and public health — and will increase costs for consumers.

Federal clean car standards directly reduce the amount of fuel burned for transportation by requiring auto manufacturers to increase fuel efficiency, saving consumers money and limiting transportation emissions. Consumer Reports says the proposed rollback could cost consumers as much as $100 billion, and the increased pollution is definitely not great for our air or oceans.

Decades of scientific monitoring show that seawater is becoming more acidic, and chemistry and carbon pollution explain the shift. About a quarter of anthropogenic carbon dioxide has been absorbed by the ocean, where it combines with seawater and triggers a series of chemical reactions that steadily move the needle toward the acidic end of the pH scale and reduces the amount of carbonate in the water. This shift matters to oysters, lobsters and other shellfish that use carbonate and calcium from seawater to build their shells. Known as ocean acidification, this phenomenon has major commercial, biological and ecological consequences for the Northeast and elsewhere.

[Adapting to an acidic ocean? The Pacific Northwest has clues for Maine]

Rising carbon dioxide levels are a triple whammy for Mook Sea Farm, an oyster farm located on the Damariscotta River in midcoast Maine. In addition to changing ocean chemistry, increased atmospheric carbon contributes to more intense rain storms, resulting in more freshwater runoff, and warming seawater temperatures. In turn, these conditions increase the abundance of Vibrio bacteria in local waters.

Mook Sea Farm and other aquaculture businesses strive to maintain normal production by altering the chemistry of the water pumped into their hatcheries and taking additional steps to ensure their shellfish are safe to eat, but these measures and harvest closures drive up the cost of business and destabilize a commercially and culturally important industry. While there is much to learn about the phenomena that cause these problems, increased carbon pollution is clearly a significant factor. They will only get worse — and new ones will undoubtedly emerge — if we do not pursue clean energy policies that reduce carbon dioxide emissions.

States have so far tackled carbon pollution on a sector-by-sector basis. The Regional Greenhouse Gas Initiative is the collective effort of Northeast and Mid-Atlantic states, including Maine, to address what were once the biggest offenders — dirty power plants. The initiative has been incredibly successful: After putting a price on carbon emissions from electricity generation and investing the proceeds in clean energy and energy efficiency, participating states have cut carbon emissions in the region by 51 percent since 2008.

[Maine and 8 other states pledge to reduce emissions by another 30 percent]

The transportation sector hasn’t seen the same level of progress. Burning fossil fuels for transportation is now responsible for the biggest share of carbon emissions in New England, and a staggering 52 percent of greenhouse gas emissions in Maine. This overwhelming statistic makes transportation emissions the obvious next focus of regional climate action, and seven Northeast and Mid-Atlantic states have already joined forces to take it on.

Maine isn’t yet among them, but the time is ripe to build a transportation-climate coalition that engages Maine’s people, businesses and policymakers in creating a shared vision for clean, modern transportation that meets community needs, invests in needed infrastructure, reduces carbon pollution and makes cars — and oceans, air and communities — great.

Kathleen Meil is Maine policy advocate at Acadia Center, a clean energy research and advocacy organization based in Rockport. Todd Capson and Esperanza Stancioff serve on the steering committee of the Northeast Coastal Acidification Network, which shares state-of-the-science information to better identify critical vulnerabilities to ocean and coastal acidification. Stancioff is also an extension professor with the University of Maine Cooperative Extension and Maine Sea Grant and serves on the Maine Ocean and Coastal Acidification Network. Capson and Stancioff are not writing on behalf of Northeast Coastal Acidification Network or Maine Ocean and Coastal Acidification Network.

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