President Biden this week will pledge to slash U.S. greenhouse gas emissions at least in half by the end of the decade, according to two individuals briefed on the plan, as part of an aggressive push to combat climate change at home and convince other major economies around the world to follow suit.

The move comes as Biden convenes a virtual summit of more than three dozen world leaders on Thursday, aimed at ratcheting up international climate ambitions and reestablishing the United States as a leader in the effort to slow the planet’s warming.

The planned U.S. pledge represents a near-doubling of the target that the nation committed to under the 2015 Paris climate agreement, when Barack Obama vowed to cut emissions between 26 and 28 percent compared to 2005 levels.

Asked for comment, a White House official said a final decision had not been made.

The Paris accord, which President Donald Trump exited but Biden promptly rejoined, was designed with the expectation that countries would embrace bigger, bolder targets over time.

“The Biden-Harris administration will do more than any in history to meet our climate crisis,” Secretary of State Antony Blinken said in a speech Monday. “This is already an all-hands-on-deck effort across our government and across our nation. Our future depends on the choices we make today.”

The administration is likely to first offer broad strokes rather than a detailed breakdown of how it will meet the more ambitious target, according to the individuals briefed on the matter, who spoke on the condition of anonymity because the plan had not been formally announced. Officials are considering a target range, they added, which could go above 50 percent at the higher end.

Still, the new pledge will offer the latest glimpse at the profound changes that Biden wants to set in motion, from decarbonizing the country’s energy sector to phasing out gas-powered vehicles. Administration officials have made clear that they see the effort not only as a climate pursuit but as a massive investment in a new generation of jobs nationwide.

“We’re going to do it in a way that’s very deliberate,” White House domestic climate adviser Gina McCarthy told reporters Monday in a call organized by the World Resources Institute. The administration wants to transition to a cleaner economy with good-paying occupations in communities that have been hardest hit by unemployment and underinvestment, she said. “It’s intended to meet the moment we are in.”

The forthcoming pledge also is meant to serve as a marker for the kind of scope — and urgency — that the Biden administration wants other countries to embrace ahead of a critical United Nations climate gathering this fall in Scotland.

Some nations, including those that are part of the European Union, already have locked in more aggressive emissions-cutting targets. The United Kingdom on Tuesday announced a commitment to reducing its emissions by 78 percent by 2035, compared to 1990 levels — a goal that the government said would take the nation more than three-quarters of the way toward reaching net zero by 2050.

But other major emitters, including China, India and Russia, have yet to spell out how exactly they intend to help put the world on a more sustainable trajectory.

China, the largest greenhouse gas polluter, has said it plans to reach peak emissions by 2030 and effectively erase its carbon footprint by 2060, though the details remain uncertain. Still, despite myriad diplomatic tensions between the two countries, the United States and China vowed Saturday to jointly combat climate change “with the seriousness and urgency that it demands.”

The world remains nowhere near meeting the central Paris aim of limiting the Earth’s warming to “well below” 2 degrees Celsius (3.6 Fahrenheit) compared to preindustrial levels — or ideally, remaining closer to 1.5 Celsius. Failure to hit those targets, scientists have warned, will result in a cascade of costly and devastating impacts.

“We are on the verge of the abyss,” U.N. Secretary General António Guterres said Monday, as a new World Meteorological Organization report detailed the intensification of extreme weather events and underscored that 2020 was one of the hottest years ever recorded.

“We are way off track,” Guterres said. “This must be the year for action — the make-it-or-break-it year.”

The International Energy Agency this week projected that global carbon dioxide emissions are set to rise by 1.5 billion tons in 2021 — the second-largest increase in history — as the world comes out of the pandemic-induced downturn. Coal demand in the electricity sector will drive the emissions rise, according to the agency.

“This is a dire warning that the economic recovery from the Covid crisis is currently anything but sustainable for our climate,” said IEA Executive Director Fatih Birol in a statement.

In the United States, the power sector represents one of the best opportunities to cut greenhouse gas emissions. On Friday, a collection of 13 utilities, including Exelon Corp., National Grid and PSGE, urged Biden to pursue a range of policies “to enable deep decarbonization of the power sector, including a clean electricity standard that ensures the power sector, as a whole, reduces its carbon emissions by 80 percent below 2005 levels by 2030.”

The Interior Department and Environmental Protection Agency, meanwhile, are already laying the groundwork to curb methane emissions from oil and natural gas drilling, in part by reviving Obama administration standards reversed under Trump. And the EPA is moving ahead to phase down the production and import of hydrofluorocarbons — which are widely used as refrigerants and in air conditioning — by 85 percent over the next 15 years, as mandated by Congress.

Passage of Biden’s new infrastructure plan, which includes generous federal support for climate priorities like electric vehicles, renewable projects and energy efficiency upgrades, could play a key role in helping the country meet its new climate pledge. But it remains unclear whether Congress will adopt the infrastructure proposal in its current form or scale it back.

For months, Biden has faced growing pressure to demonstrate that the United States not only is returning to the Paris agreement, but that it intends to back up its words with robust action.

Environmental activists, Democratic lawmakers, foreign leaders and hundreds of private companies, including Apple and Walmart, have implored the White House to make the boldest climate pledge possible. Advocacy groups and academics have published detailed analyses, demonstrating ways they say the nation could cut at least half its emissions by the end of the decade.

To craft the new pledge in the administration’s first 100 days, White House officials scrambled staffers at agencies across the government to look for funding, programs and policies that could help curb emissions in the years ahead. Agency by agency, sector by sector, federal officials tallied up the math in an effort to make Biden’s pledge credible.

Still, to reach the 50 percent target, the administration will have to make some difficult-to-guarantee assumptions about the future. For instance, that new regulations aimed at curbing emissions won’t be reversed by a future administration or the courts — even though Trump furiously dismantled key Obama-era climate policies.

While allies are likely to embrace Biden’s push to aggressively cut emissions, some Republicans have insisted that the far-reaching changes needed to cut greenhouse gas pollution so fast could harm an already struggling economy, particularly in communities that still depend on the fossil fuel industry.

Sen. Shelley Moore Capito (W.Va.), the ranking Republican on the Senate Environment and Public Works Committee, has argued that Biden’s aggressive climate actions could kill thousands of jobs in her state. On the Senate floor last month, she called the notion that new policies could quickly replace lost jobs in coal and other fossil fuels with ones in renewable energy “a fantasy world that does not exist.”

Even as the White House manages that political balancing act at home, Biden’s new pledge is meant to serve as a tool to cajole other major economies that have yet to detail their updated plans. While the United States remains the world’s second-largest emitter, roughly 85 percent of global emissions now come from other countries.

Persuading other key nations to bolster the promises they made in Paris remains critical if the world is to meet its collective goal of slowing the Earth’s warming. The targets set by countries such as China, India, Russia and Brazil could dramatically affect whether the world can reach the goals set almost six years ago.

Few experts are expecting major new commitments from other countries at this week’s White House summit. But if the willingness of the United States and its European allies to go big eventually helps nudge them in the same direction over the coming months, the gathering will have served an important purpose.

“The international community will have the opportunity to see that Biden is good for his word,” said Rachel Kyte, dean of the Fletcher School of Law and Diplomacy at Tufts University. “A lot of diplomacy is about momentum and building momentum.”