US President Donald Trump will sign an executive order on Tuesday to undo a slew of Obama-era climate change regulations, a move meant to bolster domestic energy production and create jobs, but environmentalists say the order is dangerous and vow to challenge it in court.

The decree's main target is former President Barack Obama's Clean Power Plan, requiring states to slash carbon emissions from power plants - a critical element in helping the United States meet its commitments to a global climate change accord reached by nearly 200 countries in Paris in December 2015.

The order will also rescind a ban on coal leasing on federal lands, reverse rules to curb methane emissions from oil and gas production, and reduce the weight of climate change in federal assessments of new regulations.

Trump has long telegraphed the moves, and claimed that undoing green regulation will trigger a new boom in oil, gas, and coal production and create thousands of jobs, all without harming U.S. air and water quality.

"We're going to go in a different direction," a senior White House official told reporters ahead of Tuesday's order. "The previous administration devalued workers with their policies. We can protect the environment while providing people with work."

Energy analysts and executives have questioned whether the moves will have a big effect on their industries, and environmentalists have called them reckless.

"I cannot tell you how many jobs the executive order is going to create but I can tell you that it provides confidence in this administration’s commitment to the coal industry," Kentucky Coal Association president Tyler White told Reuters.

Trump will sign the order at the Environmental Protection Agency with Administrator Scott Pruitt, Interior Secretary Ryan Zinke and Energy Secretary Rick Perry on Tuesday afternoon.

The wide-ranging order is the boldest yet in Trump’s broader push to cut environmental regulation to revive the drilling and mining industries, a promise he made repeatedly during the presidential campaign.


'ASSAULT ON AMERICAN VALUES'

Environmental groups hurled scorn on Trump's order.

"These actions are an assault on American values and they endanger the health, safety and prosperity of every American," said billionaire environmental activist Tom Steyer, the head of activist group NextGen Climate.

Green group Earthjustice was one of many organizations that said it will fight the order both in and out of court. “This order ignores the law and scientific reality," said its president, Trip Van Noppen.

An overwhelming majority of scientists believe that human use of oil and coal for energy is a main driver of climate change, causing a damaging rise in sea levels, droughts, and more frequent violent storms.

Trump and several members of his administration, however, have doubts about climate change, and Trump promised during his campaign to pull the United States out of the Paris climate accord, arguing it would hurt U.S. business.

Since being elected Trump has been mum on the Paris deal and the executive order does not address it.

Christiana Figueres, former executive secretary of the United Nations Framework Convention on Climate Change who helped broker the Paris accord, lamented Trump's order.

"The action by the U.S. to undo important domestic carbon reduction regulation in the face of the enormous momentum building globally toward a low carbon economy risks putting the country on a back-foot at a time when most Americans are looking to lead," she said in a statement.

"Trying to make fossil fuels remain competitive in the face of a booming clean renewable power sector, with the clean air and plentiful jobs it continues to generate, is going against the flow of economics," she said.

The order will direct the EPA to start a formal "review" process to undo the Clean Power Plan, which was introduced by Obama in 2014 but was never implemented in part because of legal challenges brought by Republican-controlled states.

The Clean Power Plan required states to collectively cut carbon emissions from power plants by 32 percent below 2005 levels by 2030.

Trump’s order lifts the Interior Department's Bureau of Land Management's temporary ban on coal leasing on federal property put in place by Obama in 2016 as part of a review to study the program's impact on climate change and ensure royalty revenues were fair to taxpayers.

It also asks federal agencies to discount the cost of carbon in policy decisions and the weight of climate change considerations in infrastructure permitting, and reverses rules limiting methane leakage from oil and gas facilities.