The Obama administration today announced its Clean Power Plan rules, which set limits on carbon emissions from power plants nationwide. At a White House event, President Obama trumpeted the rule as “the single most important step America has ever taken in the fight against global climate change.”

Unfortunately, the Clean Power Plan packs neither the environmental nor diplomatic punch the Obama administration has claimed. Moreover, contrary to the White House’s assertion, it offers states little flexibility and comes at enormous economic expense.

Begin with the impact on climate change. The United States is responsible for only 5 percent of the world’s total carbon emissions. In other words, “even if the United States stopped emitting all CO2 now and going forward, it would only reduce emissions by 0.15 degrees Celsius — that’s all we have to work with,” says the Cato Institute’s assistant director of the Center for the Study of Science, Chip Knappenberger.

Using the EPA’s own climate-model emulator, Knappenberger and his colleague Patrick J. Michaels determined that the Clean Power Plan rules will affect climate by less than two-hundredths of a degree Celsius by 2100, an amount so miniscule that it’s nearly impossible to measure.

Of course, developing countries are responsible for most of the world’s carbon emissions. Even the Obama administration and its allies in Congress acknowledge this, but they claim that the Clean Power Plan will help them reach a broader agreement at the United Nations climate conference in Paris late this fall.

One big problem, though: There’s little reason to expect that the developing world will make the economic sacrifices necessary to reduce emissions.

Beijing is a key bellweather, and early developments in negotiations aren’t promising. Last November, the United States and China inked a climate pact, hyped by John Kerry as an agreement of “great consequence in the fight against climate change.” But despite the Obama administration’s spin, the sacrifices in this pact are wholly one-sided.

China promises only to “stop increasing” carbon emissions by 2030 — which is to say, Beijing will allow emissions to increase for another 15 years, even as the United States requires power plants, by 2030, to reduce their carbon emissions by 32 percent from 2005 levels. China also will strive to get one-fifth of its energy from renewable sources by 2030, relying on dirtier energy to fill the rest.

China’s pollution problems are severe, and the valid environmental concerns of its citizens have increasing political importance. Nevertheless, the cadres in Beijing rely on economic growth for their legitimacy; so, with roughly 200 million Chinese living on $1.25 a day or less, it makes sense that the Chinese Communist Party hesitates to impose environmental protections that could hinder growth.

If, in 2030, Beijing is continuing to prioritize economic development over climate-change protections, the United States will have few mechanisms to force China to live up to its end of the bargain.

But in the United States, the federal government plans to strictly enforce these draconian regulations. At the same time that the EPA overstates the impact of the Clean Power Plan on climate change, it substantially understates the impact on the national economy. (In fact, the Government Accountability Office has slammed the EPA for its faulty calculations in the past.) Even so, the EPA has predicted that complying with the Clean Power Plan will be equivalent to the combined total cost of all Clean Air Act rules set forth up to 2010.

Other estimates are even more pessimistic. National Economic Research Associates predicts an eye-popping compliance costs of up to $479 billion. Though President Obama is claiming the Clean Power Plan will ultimately save Americans $85 per year on their utility bills, the NERA study found that households in 43 states will actually see double-digit price hikes. The National Black Chamber of Commerce reports that non-white families will especially suffer from these price increases in electricity, while blacks and Hispanics will also suffer the loss of 19 million jobs by 2035 as a result of the Clean Power Plan.

While the Obama administration claims that the Clean Power Plan is flexible, allowing states to figure out the best way to implement the regulations, the reality is quite different. If the EPA doesn’t approve of the plans that state legislatures submit, the agency can just impose its own methods, as it has done with the rules on regional haze.

Already, states are pushing back. Fourteen states, along with the Murray Energy Corporation and others in the energy sector, launched a recent challenge to the Clean Power Plan in federal court, though a judge ruled in June that the suit was premature. More than a dozen states anticipate taking future legal action against the regulations, and others have threatened to defy the EPA’s mandates outright. As these legal challenges continue, congressional Republicans are also pushing legislation to scale back the EPA’s rules.

The Clean Power Plan exemplifies bad policy, deeply harming the economy without meaningful environmental or diplomatic achievements. States and the other two branches of federal government should act fast to halt this wrongheaded executive action.

— Jillian Kay Melchior writes for National Review as a Thomas L. Rhodes Fellow for the Franklin Center. She is also a senior fellow at the Independent Women’s Forum.