WASHINGTON DC – Forty heads of state gathered Thursday for a two-day virtual climate summit hosted by the White House, as President Biden set a new U.S. target for lowering emissions.

The White House announced that by 2030 the U.S. expects to reduce its carbon emissions by between 50 and 52 percent compared to 2005 levels.

The gathering of world leaders and Biden’s plans to reduce greenhouse gas emissions marked the administration’s biggest steps on climate. Here are the main takeaways.

  • The U.S. is back

Foreign leaders hailed the return of the U.S. as a leader on climate issues following four years of disengagement by the Trump administration.

“I’m delighted to see that the United States is back to work together with us in climate politics,” German Chancellor Angela Merkel said at the summit, “because there can be no doubt about the world needing your contribution, if we really want to fulfill our ambitious goals.”

European Commission President Ursula von der Leyen added: “It is so good to have the U.S. back on our side in the fight against climate change. Together we can go faster and get further, and together we will win the future.”

The Biden administration has repeatedly emphasized its desire to return the U.S. to a position of international leadership on climate after then-President Trump withdrew from the Paris Climate Agreement and rolled back a number of energy and climate regulations.

“America is back. We rejoined the Paris Agreement and are ready to rally the world to tackle the climate crisis. Let’s do this,” Biden tweeted.

In addition to organizing the summit and rejoining the Paris agreement, the Biden administration has taken a number of steps to reverse Trump-era moves relating to climate and the environment. This includes revoking the permit of the Keystone XL pipeline, along imposing an indefinite moratorium on new leases for oil and gas drilling on federal lands.

  • Biden’s proposal draws criticism from left, right

While the Biden’s emissions target drew praise from many Democratic and U.S. allies, both progressives and conservatives criticized the administration’s plans, but for different reasons.

A number of progressive groups said the U.S. needs to aim for at least a 70 percent reduction compared to 2005 levels in order to promptly address climate change.

“The only way to get the rest of the world to take climate action to the degree we need is if the United States – the richest country in the world and the biggest historical polluter – does our fair share first,” said Sunrise Movement Political Director Evan Weber in a statement, calling Biden’s target “ nowhere near enough.”

“If the U.S. does not achieve much, much more by the end of this decade, it will be a death sentence for our generation and the billions of people at the frontlines of the climate crisis in the U.S. and abroad,” Weber added.

Republicans, many of whom did not want Biden to return to the Paris Agreement, argued that the new targets will be bad for U.S. workers.

“Today’s announcement shows how this unrealistic promise will only crush American families and workers,” said House Minority Whip Steve Scalise (La.) in a statement that included criticism from more than 25 Republican lawmakers who are members of the House Energy Action Team. The group chastised Biden for “pledging to shackle the United States to a new sweeping and unattainable Paris Agreement commitment.”

The Biden administration contends that the transition to clean energy will bring new jobs to replace fossil jobs that are lost.

Mike Pompeo, who served as secretary of State in the Trump administration and is considered a potential 2024 presidential contender, slammed Biden’s return to the Paris Agreement.

“The Paris Climate Accord has no enforcement mechanism and will cost the American people a fortune with no benefit. It may make the Left ‘feel good’ to rejoin the deal, but it simply doesn’t produce,” he tweeted Thursday. “If change is what you’re looking for, this ain’t it.”

  • U.S. plan is ambitious, but comparatively it’s a mixed bag

Biden’s emissions target is one of the more ambitious among major industrialized economies, though the U.K. and European Union are being more aggressive, depending on the point of comparison.

The U.S. is using 2005 emissions level, the approximate high point for U.S. emissions, as its starting point, whereas European nations tend to make 1990 their basis of comparison. Compared to 1990 levels, the U.S. target would represent a reduction of 43 percent, compared to 68 percent for the U.K. and 55 percent for the EU, according to a New York Times analysis.

China, meanwhile, expects its emissions to peak by 2030. The world’s top emitter of greenhouse gases has argued it needs more time to reduce emissions due to industrializing more recently than other major economies in Europe and North America.

Japan and Canada both announced new emissions targets at the summit, with Japan aiming to reduce its emissions by at least 46 percent compared to 2013 levels and Canada now committing to reduce its emissions by between 40 percent and 45 percent compared to 2005 levels.

Some environmental advocates have argued that the principal measure of the effectiveness of a reduction should be how close it gets a country to net zero emissions by 2030.

“Canada, 40 to 45 [percent] is nowhere near that,” Jake Schmidt of the Natural Resources Defense Council told The Hill.

“The main reason why they’re not putting forward a stronger target is because they have inflated tar sands numbers, and tar sands is such a big source of their growing missions that inflate their number makes it look harder,” he added, referring to a carbon-intensive type of oil.

Japan, however, is on a much better track, Schmidt said.

“The fight’s going to be, how do they move quickly to the 50 percent target, because that I think is the kind of target that puts them in the leadership group of countries that are committing to be halfway to net zero by the end of this decade,” he said.

  • Officials stress need for private sector help

Climate summit participants emphasized the need for cooperation with the business community, saying international goals will require collaboration with the finance sector.

U.S. Climate Envoy John Kerry said meeting emissions targets “will require mobilizing finance at an absolutely unprecedented level, and it will require governments to help facilitate the net-zero transition around the world.”

“Given the magnitude of this challenge … governments alone cannot possibly find all the necessary investment,” Kerry added. “There’s no government in the world that has enough … in their budgets to be able to provide what we need to make this transition.”

Treasury Secretary Janet Yellen added that while Biden intended to devote the “full capacity of the U.S. government” to reducing emissions, “past efforts to support private investment have not achieved anywhere near the scale needed to green the global economy.”

  • Biden’s goal will require significant domestic policies to achieve success

It’s one thing to set a goal, but quite another to meet it. And cutting the country’s emissions in half will require an ambitious set of policies to go with it.

The White House did not provide a specific roadmap laying out how it plans to achieve the emissions reductions. But in a fact sheet outlining the 50 percent target, the administration detailed some policies it’s considering.

These include requiring a carbon-free power sector by 2035, reducing vehicle tailpipe emissions and increasing fuel efficiency for cars and trucks. Other approaches include

supporting efficiency upgrades and electrification in building through retrofit programs and adopting updated energy codes for new buildings.

At the summit, Biden touted his $2.3 trillion infrastructure plan, which aims to make electric vehicles more affordable, incentivize building electric vehicle charging stations, retrofit buildings, replace lead pipes and modernize the nation’s electrical grid.

“When people talk about climate, I think jobs. Within our climate response lies an extraordinary engine of job creation and economic opportunity, ready to be fired up,”  he said.

But Biden’s infrastructure proposal faces a rocky path in Congress, and failure to pass the eventual legislation would deal a significant blow to the administration’s climate goals.

This story was published in The Hill.