President Biden on Thursday committed the United States to slashing its greenhouse gas emissions by as much as 52 percent by 2030, a pledge that will require fast and far-reaching changes in how the country powers its homes and drives it cars.

The highly anticipated announcement doubles a target set by President Barack Obama in 2015 as part of the Paris climate accord, by vowing the nation will reduce its emissions between 50 and 52 percent by 2030 compared with 2005 levels. Biden plans to formalize the goal in a submission to the United Nations.

The show of renewed American commitment was a striking contrast to the four years of vocal climate denial by the Trump administration. The move comes as the White House convenes 40 world leaders for a two-day virtual Earth Day summit aimed at fueling similar ambition around the globe.

“Meeting this moment is about more than preserving our planet,” Biden declared, speaking from a TV-style set. “It’s about providing a better future for all of us,” he said, calling it “a moment of peril but a moment of opportunity.”

Many leaders attending the summit are expected to make new emissions reductions of their own, including those from China and India. The UK and European Union have committed to slash emissions by 68 percent and 55 percent, respectively, by 2030. China, the world’s biggest emitter, has vowed to reach peak emissions by 2030 and be carbon neutral by 2060.

Only three months have passed since the United States, a driving force behind the Paris agreement, rejoined the accord after it became the only nation in the world to formally walk away from the pact under President Trump. While numerous American states, cities and businesses around the country continued to push forward with efforts to scale back emissions, the federal government remained largely on the sidelines.

Biden’s renewed carbon-cutting pledge and the summit are intended to reestablish US leadership on international climate action and to kick-start momentum ahead of a key UN gathering this fall in Scotland, where nations are expected to arrive with bold new blueprints for how they intend to help slow the Earth’s warming.

“The signs are unmistakable, the science is undeniable and the cost of inaction keeps mounting,” Biden told the summit.

While the summit is an international one, Biden’s speech was also aimed at a domestic audience, focusing not just on America’s obligation to help cut its global emissions but on the jobs he believes are available by greening the US economy.

Biden so far has proposed a $2 trillion infrastructure package that would assist the transition away from fossil fuels and toward clean energy, while promising to create green jobs. If passed, the legislation would be one of the largest federal efforts ever to reduce emissions.

“The countries that take decisive actions now” to tackle climate change, Biden said, “will be the ones that reap the clean energy benefits of the boom that’s coming.”

China’s President Xi Jinping, whose country is the world’s biggest emissions culprit, followed by the United States, spoke first among the other global figures invited to the summit, and said China would work with America in cutting emissions.

Russia’s president Vladimir Putin, whose government has been publicly irate with the Biden administration made no mention of his feud in his own climate remarks, a live presentation.

“Russia is genuinely interested in galvanizing international cooperation so as to look further for effective solutions to climate change as well as to all other vital challenges,” Putin said. Russia the world’s fourth-biggest emitter of climate-damaging fossil fuel fumes.

In its pledge Thursday, the Biden administration did not spell out precisely how it plans to meet its new target or how much individual sectors of the economy would have to reduce their emissions. Rather, the White House plans to detail the various sectors where it believes significant emissions cuts can happen in the years ahead.

Much of that includes policies Biden has previously identified: decarbonizing the power sector by 2035, boosting renewable energy technologies, electrifying millions of buildings around country, mandating more fuel-efficient cars and trucks, incentivizing sustainable agriculture practices and targeting emissions of methane, hydrofluorocarbons and other potent, short-lived climate pollutants.

The two-day summit comes at a time when scientists are warning that governments must take decisive action to prevent global temperatures from rising more than 1.5 degrees above preindustrial levels. The consequences of exceeding that threshold includes mass species extinctions, water shortages and extreme weather events that will be most devastating to the poorest countries least responsible for causing global warming.