In the most ambitious U.S. effort to stave off the worst of climate change, President Joe Biden signed executive orders Wednesday to transform the nation’s heavily fossil-fuel powered economy into a clean-burning one, pausing oil and gas leasing on federal land and targeting subsidies for those industries.

The directives aim to conserve 30 percent of the country’s lands and waters in the next 10 years, double the nation's offshore wind energy, and move to an all-electric federal vehicle fleet, among other changes. Biden’s sweeping plan is aimed at staving off the worst of global warming caused by burning fossil fuels.

But his effort it also carries political risk for the president and Democrats as oil- and coal-producing states face job losses from moves to sharply increase U.S. reliance on clean energy such as wind and solar power.

“We can’t wait any longer'' to address the climate crisis, Biden said at the White House. ”We see with our own eyes. We know it in our bones. It is time to act.''

He said his orders will “supercharge our administration's ambitious plan to confront the existential threat of climate change.”

Biden has set a goal of eliminating pollution from fossil fuel in the power sector by 2035 and from the U.S. economy overall by 2050, speeding what is already a market-driven growth of solar and wind energy and lessening the country's dependence on oil and gas. The aggressive plan is aimed at slowing human-caused global warming that is magnifying extreme weather events such as deadly wildfires in the West and drenching rains and hurricanes in the East.

Biden acknowledged the political risk, repeatedly stating his approach would create jobs in the renewable energy and automotive sectors to offset any losses in oil, coal or natural gas.

“When I think of climate change and the answers to it, I think of jobs,'' Biden said. "These aren’t pie-in-the-sky dreams. These are concrete actionable solutions. And we know how to do this.''

In a change from previous administrations of both parties, Biden also is directing agencies to focus help and investment on the low-income and minority communities that live closest to polluting refineries and other hazards, and the oil- and coal-patch towns that face job losses as the U.S. moves to sharply increase its reliance on wind, solar and other other energy sources that do not emit climate-warming greenhouse gases.

Biden pledged to create “millions of good-paying, union jobs” building electric cars, installing solar panels and wind turbines, and performing specialized work to cap abandoned walls, restore mine-scarred land and turn old industrial sites "into the new hubs of economic growth.''

Even so, Republicans immediately criticized the plan as a job killer.

“Pie-in-the-sky government mandates and directives that restrict our mining, oil, and gas industries adversely impact our energy security and independence,'' said Rep. Cathy McMorris Rodgers of Washington state, the top Republican on the House Energy and Commerce Committee.

Biden also is elevating the warming climate to a national security priority, directing intelligence agencies, the military and others to do more to prepare for the heightened risks. The conservation plan would set aside millions of acres for recreation, wildlife and climate efforts by 2030 as part of Biden’s campaign pledge for a $2 trillion program to slow global warming.

President Donald Trump, who ridiculed the science of climate change, withdrew the U.S. from the Paris global climate accord, opened more public lands to coal, gas and oil production and weakened regulation on fossil fuel emissions. Experts say these emissions are heating the Earth's climate dangerously and worsening floods, droughts and other natural disasters.

Currently, 61% of the nation's electric power comes from natural gas and coal, 20% from nuclear and 17% from wind, solar and other renewable energy, the U.S. Energy Information Administration says.

Georgia Tech climate scientist Kim Cobb said that "if this Day 7 momentum is representative of this administration’s 4-year term, there is every reason to believe that we might achieve carbon neutrality sooner than 2050," even as key roadblocks lie ahead.

Biden's actions came as his nominee for energy secretary, former Michigan Gov. Jennifer Granholm, faced deep skepticism from Republicans as she tried to pitch the president’s vision for a green economy.

“The last Democratic administration went on a regulatory rampage to slow or stop energy production,” said Wyoming Sen. John Barrasso, a leading Republican on the Senate Energy and Natural Resources Committee. "I’m not going to sit idly by ... if the Biden administration enforces policies that threaten Wyoming’s economy.''

Granholm, whose state was devastated by the 2008 recession, promoted emerging clean energy technologies, such as battery manufacturing, as an answer for jobs that will be lost as the U.S. transitions away from fossil fuels.

Former Secretary of State John Kerry, now Biden's climate envoy, said oil, gas and coal workers “have been fed a false narrative'' that ”somehow, dealing with climate is coming at their expense. No, it’s not. What’s happening to them is happening because of other market forces already taking place.''

Instead of possible black lung disease, a miner would have a brighter future as a solar power technician, Kerry said. "The same people can do those jobs, but the choice of doing the solar power one now is a better choice.''

The oil industry said curtailing domestic production will lead to an increase in imported oil.

“I don’t think any American wants to go back to the days of being held hostage to foreign entities that don’t have America’s best interest at heart as we lose American energy leadership,” said Mike Sommers, president of the American Petroleum Institute.

Sommers and other industry leaders warned that states could lose hundreds of thousands of jobs and critical funding. Nearly one-third of New Mexico’s state budget comes from oil and gas, said Ryan Flynn, president of the New Mexico Oil and Gas Association.

Biden's directive to double energy production from offshore wind comes after the Trump administration slowed permit review of some giant offshore wind turbine projects. Significantly, he is directing agencies to eliminate spending that acts as subsidies for fossil fuel industries.

The pause in onshore leasing is limited to federal lands and does not affect drilling on private lands, which is largely regulated by states. It also will not affect existing leases and could be further blunted by companies that stockpiled enough drilling permits in Trump’s final months to allow them to keep pumping oil and gas for years.

The order exempts tribal lands, mainly in the West, that are used for energy production.

Biden also directed U.S. agencies to use science and evidence-based decision-making in federal rules and announced a U.S.-hosted climate leaders summit on Earth Day, April 22.