Attempting to make major changes through executive action is a strategy with many pitfalls, says Michael McConnell, a constitutional law scholar at Stanford University. Executive actions lack permanence. Courts could find that the president or executive agencies overstepped. “In general, an executive can move faster when it acts on its own, but the danger is that nine or 13 months later, they’re going to find that what they’ve done is struck down,” McConnell said.

Legal challenges to Obama’s climate actions are all but guaranteed. Even if they aren’t successful, they may delay implementation of new rules and regulations, making progress in Obama’s remaining four years difficult.

Pursuing climate change through the White House rather than Congress also runs the risk of being a slapdash approach to the problem rather than a comprehensive solution.

“Long term, you do need Congress’s support,” Alden Meyer, director of strategy and policy for the Union of Concerned Scientists, said of the administration. “To get the kind of deep reductions and the real transition away from polluting fossil fuels over the next several decades, you need to have some bipartisan support; you need to have Congress going along with it and future presidents also wanting to build on this. I think [Obama administration officials] know that.”