Leading Japan and Canada in raising commitments at a summit whose promises bring the world closer to limiting the worst climate change, President Joe Biden on Thursday sharply ramped up US ambitions on slashing greenhouse gas emissions.
Putting the United States back at the forefront on climate, Biden told a virtual Earth Day summit that the world's largest economy will cut emissions blamed for climate change by 50 to 52 percent by 2030 compared with 2005 levels.
"The cost of inaction keeps mounting. The United States isn't waiting," Biden told the opening of a two-day summit of 40 leaders including the presidents of rivals China and Russia.
"We have to step up," Biden said. "We have to take action — all of us."
Biden's early environmental push marks a drastic shift from his predecessor Donald Trump — but quickly raised questions on whether the United States can carry out its promises if another climate-skeptic president is elected in the future.
Combined with announcements expected by other leaders, the White House said that nations accounting for more than half the world's economy have now committed to action to keep the planet's temperature within 1.5 degrees Celsius (2.7 Fahrenheit) above pre-industrial times, the level scientists say is needed to avoid the most severe effects of climate change.
Japanese Prime Minister Yoshihide Suga, who discussed climate last week when he was Biden's first foreign guest, significantly raised the goals of the world's second largest developed economy to cutting emissions by 46 percent in 2030 compared with 2013.
Canadian Prime Minister Justin Trudeau, another early ally of Biden, boosted ambitions of his energy-exporting country to reductions of 40-45 percent below 2005 levels, compared with an earlier target of 30 percent.
"We must take action now. Because there's no vaccine against a polluted planet," Trudeau said.
The European Union this week confirmed its own ambitious goals and former bloc member Britain on the eve of Biden's summit released the most far-reaching targets of any major economy with 78 percent cuts from 1990 levels by 2035.
British Prime Minister Boris Johnson called Biden's pledge "a game-changer" that will "have a transformative impact in the global fight against climate change."
Britain in November will host a UN conference in Glasgow that aims to upgrade the 2015 Paris Agreement.
Under Paris, former president Barack Obama said the United States would cut emissions by 26 to 28 percent by 2025 — a goal that Biden, his former vice president, has now dramatically scaled up.
Biden's action raises the pressure on China — by far the world's largest carbon emitter.
China's relationship with the United States has sharply deteriorated in recent years but Beijing nonetheless agreed to cooperate on climate during a pre-summit visit by John Kerry, the former US secretary of state who is now Biden's globe-trotting climate envoy.
Addressing the virtual summit, President Xi Jinping reiterated his promise last year to reach carbon neutrality by 2060.
China will "pursue a green and low-carbon path to development," Xi said, saying Beijing "looks forward to working with the international community, including the United States."
Xi promised that China would curb the use of coal. But environmentalists have voiced alarm at the lack of immediate action to curb coal, which is the dirtiest form of energy but politically sensitive due to mining jobs.
Prime Minister Narendra Modi of India — which is the third largest emitter, but far lower than the West on a per capita basis — also made no new pledges but promised a new "partnership" with Biden to mobilize green investment and urged a greater "lifestyle change" to fight climate change.
In a brief glitch at the summit, Secretary of State Antony Blinken cut off a pre-recorded video from French President Emmanuel Macron to hear from Russian President Vladimir Putin, who appeared to be live and impatient to speak.
Putin, whose early relations have been especially tense with Biden, said that Russia was fulfilling its obligations to fight climate change.
Comparisons between major economies are difficult as the United States takes 2005 as its baseline while the Europeans use 1990, the date set in the landmark Kyoto Protocol.
But the Rhodium Group in a recent analysis said that Biden's goals, which had been expected for weeks, were roughly on a par with ambitions of the European Union, the historic champion of international action on climate, when assessing from the 2005 baseline.
Trump pulled out of Paris, calling it unfair to coal miners and the energy industry. But the United States is still largely on track to meet Obama's goals thanks to commitments by states, especially California, and a sharp drop in industrial production during the Covid-19 pandemic.
Nonetheless, a UN report late last year said that the world was on course for warming of three degrees Celsius — a level at which the planet is forecast to see many glaciers and ice caps melt, low-lying areas submerged and increasingly severe droughts, floods and disasters that could trigger famine and mass migration.
Biden has proposed a $2 trillion infrastructure package that includes a major focus on greening the economy, including investment in renewable energy, electric cars and public transportation.
In the face of Republican opposition on climate, Biden has cast green energy as a way to create well-paying jobs and has already set a goal of US electricity going completely carbon-free by 2035.
The White House also vowed to support energy innovations and "carbon sinks" such as forests that suck up pollution and to prioritize action against extremely pollutant gases such as methane.
Samantha Gross, director of the energy security and climate initiative at the Brookings Institution, said that Biden was relying on incentives after Obama's push on regulation was largely killed off once Trump won.
Europe, she noted, was on a more narrowly focused path of raising the price on carbon to force reductions.
The emerging US approach is "focusing on what works, and multiple pathways being possible," she said, "and that's something about the US that I find encouraging."