John Podesta has his eyes on 2018 and 2020, marking those critical election years as the "battle lines" upon which Democrats can make political gains in order to save the Paris climate agreement.

President Trump announced Thursday at the White House that the U.S. will withdraw from the international accord, which was negotiated during the Obama administration, that aims to reduce global greenhouse gas emissions.

Podesta, a former Obama counselor and campaign chairman for Hillary Clinton's 2016 presidential campaign, notes in an op-ed for the Washington Post that despite the pledge to exit, the U.S. won't actually fully exit until 2020 under the terms of the agreement. That would give the Democrats a chance to catch up and surpass the Republican majorities in the House and Senate in the 2018 midterms, and Podesta also mentioned 2020, when Trump will presumably seek re-election.

"That means that the battle lines are formed for the 2018 and 2020 elections," Podesta wrote. "Every politician between now and then must answer the question of whether she or he stands with Trump and fossil-fuel special interests or stands with the health and well-being of our children and our planet."

Calling it an "attack on the environment," Podesta also said that Trump's departure from the climate accord would not only hurt the American economy but also spark environmental disaster, impede the food supply chain and create "climate-induced human migration and global insecurity."

Clinton also wrote a brief message on Twitter to express her thoughts about the Paris agreement exit, calling it a "historic mistake."