President Obama has just “put climate change back on the national agenda,” said Mark Tercek in HuffingtonPost.com. Declaring that the U.S. should not condemn “future generations to a planet that’s beyond fixing,” Obama this week announced a wide-ranging plan to reduce greenhouse gas pollution and prepare the country for a world of rising temperatures. The president said he would use executive authority to bypass a deadlocked Congress and mandate major reductions in carbon emissions from the country’s power plants—the bulk of which burn coal and account for roughly one third of the U.S.’s greenhouse gas production. His ambitious program would free up federal land for new solar and wind energy projects, and increase funding to help cities and states adapt to rising sea levels and increasingly extreme weather. Obama’s decision to act unilaterally “is reason to celebrate,” said Jason Bordoff and Michael Levi in The New York Times.But it’s “also an occasion for mourning.” The global atmospheric concentration of carbon dioxide reached a milestone of 400 parts per million in March, the highest in several million years—yet congressional Republicans continue to insist that no action to restrain emissions is necessary.

They’re right, said NationalReview.com in an editorial. Contrary to the predictions of climate models, recent scientific research has found that global warming is “slowing, and some estimates show it having been reversed.” The warmest year on record was 1998, and for reasons climatologists admit they don’t understand, the rate of warming over the last 15 years was markedly lower than in the preceding 20 years. Clearly, the science isn’t settled. Hurting our economy to make minor emissions reductions “is not justified by science, by economics, or by sensible policy analysis.” Obama’s plan to single-handedly save Earth without the consent of Congress is “grandiose even for him,” said The Wall Street Journal. By declaring “war on carbon,” Obama will cause higher costs to “ripple through the energy chain”—the last thing the country needs at a time when the economy remains sluggish and 12 million Americans can’t find work.

Taking “a wait and see approach” on climate change would be “a recipe for certain disaster,” said Dana Nuccitelli in Guardian.co.uk. It’s true that the warming of surface air temperature has slowed, but studies suggest that about 90 percent of the planet’s warming is being absorbed by the oceans. Sooner or later, that stored heat will be unleashed, melting polar ice caps and warming the atmosphere at a suddenly accelerated rate. Any meaningful attempt to prevent this disaster will cause some economic pain, said Matthew Yglesias in Slate.com. But allowing air pollution to continue unabated, locking in a future of rising sea levels, wild storms, heat waves, and floods, “is much worse for the economic long-term than the short-term pain of higher electricity prices.”

Yet the odds that Obama’s “initiative will noticeably slow global warming are pretty slim,” said Megan McArdle in TheDailyBeast.com. The developing world, led by China and India, is building thousands of coal-burning factories, power plants, and cities that will overwhelm any reduction in emissions made by the U.S. And few Americans are actually willing to make the painful lifestyle choices—such as giving up air-conditioning and cutting back on air travel—necessary to seriously reduce our own carbon emissions. Without real global cooperation, the president’s plan is doomed to be just another footnote in the history of our warming planet.