No wonder U.S. President Barack Obama hopped on a flight to Europe this week. On June 2, when his environmental chief rolled out a massive proposed rule that would force power plants to cut carbon dioxide emissions 30 percent by 2030 (relative to 2005 levels), Republicans vied to lambaste the plan, which House Speaker John Boehner dismissed simply as "nuts."
In Europe, Obama can expect a kinder reception. The European Union climate chief, Connie Hedegaard, hailed the proposal as the "strongest action ever taken by the U.S. government to fight climate change" -- even as she urged every country, the United States included, to do "even more."
But amid the hullabaloo, everyone is forgetting a key detail: Actions by the executive branch are only as strong as the next presidential election. The regulations, which target coal plants in particular, can always be rolled back by a new administration.
Just ask Australia and British Columbia, where, at this very moment, politicians are rejiggering their predecessors' strong carbon policies.
And as U.S. environmental rules go, the carbon one may be especially easy to knock down because of its late implementation schedule -- this week's proposal, from the Environmental Protection Agency (EPA), calls on states to have a plan for implementation in place by 2016, with actual emissions reductions not required until 2020.
"Even if the Obama administration is able to adopt stringent new rules, and such rules survive court challenge, they could be vulnerable to revision by future administrations," said Jonathan Adler, who directs Case Western Reserve University's Center for Business Law & Regulation.
Rolling back the power plant measure wouldn't be a snap, because it would require time-consuming steps like a public comment period. But a future administration wanting to void it in a hurry will have a clear precedent, Adler said: The Obama administration's expanded use of executive-branch discretion.
"If a Republican president were to build upon these precedents, that president would (have) a far-reaching authority to, in effect, waive existing regulatory requirements while building support for regulatory or legislative changes," he said.
In other words, Obama's eagerness to use executive authority -- the implementation of Obamacare being a classic example -- could come back to haunt him, if a Republican takes over.
And make no mistake, Republicans will run on the issue, even as environmentalists are gearing up to champion climate change action in the hopes of wooing the general public.
The likes of Sen. Rand Paul, Ky., and Texas Gov. Rick Perry are probably thinking up campaign zingers even now, to rouse the electorate against higher electric power prices and federal overreach.
So the risk is that carbon policies can be politically fickle, and in the arena of global climate change regulations, there is precedent. Australia and British Columbia both adopted aggressive carbon regulations years ago, only to see a change of government, and new economic considerations, prompt a rethink.
In the United States, Democrats know all too well that environmental measures can be reversed. The classic case is the U.S. stance toward the Kyoto Protocol, the global treaty to cut carbon emissions.
Bill Clinton signed Kyoto shortly before leaving office, and incoming President George Bush promptly renounced it.
On a smaller scale, the Ohio legislature just rolled back renewable energy requirements put in place seven years ago, to environmentalists' dismay.
American environmentalists hope that climate action will take on the aura of inevitability, as it tackles one of the defining issues of our time. Perhaps that is how things will unfold, and the country will indeed get on board, especially as the administration emphasizes how cutting coal-plant pollution can clean the air and improve health.
But in the shorter term, there is no doubt that conservatives will use the EPA action as a cudgel in the 2016 election.
After all, Mitt Romney came within four points of winning in 2012, and he was rolling out commercials with lines like: "We have 250 years of coal. Why wouldn't we use it?"
Hillary Clinton, if she runs, will presumably be bound to the EPA's carbon-cutting because of her service in the Obama administration and because her husband signed Kyoto.
Not until the rule makes it through the courts -- and the 2016 election -- will it really be time for environmentalists to celebrate.
Kate Galbraith, is a San Francisco-based journalist who writes about energy and climate issues. Her work has appeared in the Texas Tribune, the New York Times and the Economist, and she is co-author of "The Great Texas Wind Rush."