“I agree with you, I want to do it, now make me do it,” Franklin D. Roosevelt told leftists during his presidency. As he understood, politicians respond to those who are best able to pressure them. And while climate activists can’t write out big checks in Manhattan and Houston, they can field whopping crowds on the National Mall—something they proved last Saturday at a protest against the Keystone XL pipeline. The recent Keystone protests should motivate the president to take real action on climate change, which could quite reasonably be called the greatest and most pressing crisis of our generation.

The Keystone XL pipelines would bring oil extracted from the Alberta tar sands to the Gulf Coast for refinement and export. Climate activists see its construction as an existential threat to anti-global warming efforts. Many in the Great Plains are also concerned, for if ruptured, the pipeline could leak into the Ogallala Aquifer, the breadbasket region’s main source of water. Menaced by an end-of-days situation, climate activists, led by Bill E. McKibben ’82, a former Crimson president, and James E. Hansen, have rallied their energies, staging the biggest environmental protests seen since the movement’s 1970s heyday and the nation’s largest-ever climate change protest.

This brand of activism, drawing its participants from college campuses including our own, is just as necessary now as it was during the New Deal. During the 2008 presidential campaign, President Obama pledged that by 2050 he would lower carbon emissions by 80 percent and invest $150 billion in green energy. But those promises never materialized. The president expended precious political capital on health care reform and an overhaul of financial regulation, making it easier for coal-state Democrats to kill cap-and-trade legislation. If anything, his first term saw a retreat on environmental issues, with the president caving to the oil industry’s demands for more off-shore drilling and overruling the Environmental Protection Agency’s ozone directives.

These recent protests were seen as part of a craven political calculus, and thankfully they seem to have been only that. The high levels of participation from Harvard and other students are not only enormously inspiring, but they also point to the growing impatience of the American public with the president’s failure to take real action on the urgent problem of climate change and should create the political will for the federal government to do so. At his second inauguration, the president focused on the “the fierce urgency of now,” a theme into which climate action, cast as a moral and political imperative, figured significantly. But given Republican control of the House, chances of a congressional deal are nil.

Yet the president is not powerless. He has signaled a willingness to use executive orders to advance the environmentalist cause. Now, we have to make him do it.