The Obama administration, with partners Canada and Mexico, made combating the threat of climate change a formal part of the landmark North American Free Trade Agreement on Wednesday.

The countries agreed to a new five-year plan that promotes "Green Growth" strategies, requiring more investments in transportation and clean energy technologies to reduce emissions. The plan also calls for the promotion of emission control zones to limit the use of fossil fuels, while also funding local communities to take action to limit environmental degradation.

Environmental Protection Agency Administrator Gina McCarthy said the decision to address climate change under the environmental subset of the 20-year-old trade accord is not "simply about the environment," but about creating a sustainable economic plan to counter the "big environmental challenge" of climate change.

Combating climate change has been a major part of President Obama's agenda in his second term. Many scientists say rising emissions from burning fossil fuels are driving manmade global warming, causing increasing droughts, floods and severe weather.

Wednesday's decision comes as NAFTA has become a hot-button topic in the run-up to the 2016 presidential election. Critics of the trade agreement regularly blame it for eroding the U.S. industrial base and taking away American jobs. Presidential contenders have used the trade agreement to distance themselves from Democratic hopeful Hillary Clinton, whose husband Bill Clinton was president when the NAFTA deal was pushed through.

Environmental officials from the U.S., Canada and Mexico gathered in Boston Wednesday to approve a new strategic plan under the trade accord's environmental agreements to guide them in taking actions to adapt to climate change and mitigate harmful emissions over the next five years.

"The objectives for the work under this strategic priority are to minimize threats posed by climate change by taking actions to plan for and implement climate change adaptation and mitigation measures that will protect human health and the environment from the effects of climate change," according to the new strategic plan.

McCarthy presided over the Commission on Environmental Cooperation, established under the NAFTA trade accord 20 years ago, to announce the new five-year strategic plan. Mexico takes over the chairmanship of the commission Wednesday from the U.S.

The economic benefits for North America that McCarthy underscored in her opening remarks are referred to in the plan as "Green Growth." Although the plan admits there are "a number of definitions" of what constitutes Green Growth, the commission concedes that at its "heart" Green Growth "is economic growth that is environmentally sustainable."

Nevertheless, "Promoting green growth implies both opportunities and risks," the report reads. "For example, as we reduce or change the use of natural resources, minimize waste or develop new environmentally friendly products and services, the demand for such products and services could increase [potential economic growth] while also decreasing the pressure on natural resources, which could result in the opportunity to create new, more sustainable patterns of development."

The plan says the risks stem from "the mismanagement of natural resources" that would impede economic growth, with increasingly unmanageable pressure on different segments of our global economy."

The bottom line: Green Growth will require more investment in transportation infrastructure and clean energy technology. Part of the plan to mitigate transportation emissions comes from establishing North American Emissions Control Areas, which are primarily focused on water-based shipping to reduce emissions from hauling vessels' fossil fuel emissions. EPA has been working with the shipping industry and a number of international groups to hash out the details of the emission reduction areas that would require lower emission fuels and retrofitted engines with which to comply.

"The plan itself is ambitious," but "realistic," McCarthy remarked. "We know we are heading into a challenging time … and we want to be ahead of the race" in facing down climate change, she said.

Her counterparts from Canada and Mexico expressed their full support for the plan, stressing the plan's provisions for supporting indigenous and local communities to confront environmental challenges.