The newly elected President of the United States, Joe Biden, insisted during his electoral campaign on his ambitions in environmental matters.

Relieved by Donald Trump's defeat, climate advocates are now hoping that his successor will propose significant progress.

The community of climate advocates expressed their deep relief after the election of Joe Biden, seeing it as hope for the planet despite the titanic reforms to be implemented to limit the devastating impacts of global warming.

Activists and scientists feared that the planet would take another blow with four more years in the White House of a president who thwarted efforts to fight against climate change.

But Joe Biden's victory is a game-changer: the Democrat promised to bring the United States back to the Paris Climate Agreement - which Donald Trump's decision officially took them out of on November 4 - and he presented a 1.7 trillion dollar plan to achieve carbon neutrality by 2050.

>> LIVE - US Presidential: Joe Biden, elected and acclaimed, calls for unity

Betting on the ecological recovery

"Joe Biden's historic victory is the first step to avert climate catastrophe," Greenpeace executive director Jennifer Morgan commented on Twitter, calling on Joe Biden to be the climate "champion" the world needs.

"The Biden-Harris administration has a historic opportunity to implement one of the world's largest green stimulus efforts to steer the U.S. economy toward sustainable emissions reductions while rebuilding the country and creating a fairer society, "declared Laurence Tubiana, one of the architects of the Paris Agreement, which aims to limit warming below + 2 ° C, ideally + 1.5 ° C, compared to the pre-era era. -industrial.

"It's a new day for the climate, the environment and the American people. A better tomorrow is possible," said Andrew Steer, head of the World Resources Institute think tank.

But "there is not a minute to lose," he insisted.

In order not to exceed + 1.5 ° C and to limit the scale of climatic disasters which are already increasing across the planet, global greenhouse gas emissions should in fact be reduced by almost 50% by 2030, according to UN climate experts (IPCC).

A decline which requires radical reforms of the world economy.

But an ambition that would be a little less out of reach with Joe Biden in the White House, believe some experts.

>> READ ALSO -

Paris Agreement on the climate: Trump or Biden, what will it change?

Achieve carbon neutrality by 2050

For the Climate Action Tracker group, this victory could thus be a "tipping point" to get "very close" to the target of + 1.5 ° C.

For this to happen, the United States' promise of carbon neutrality by 2050 would have to be kept, as would recent Chinese, European and Japanese commitments in this area.

"If the United States adopts the goal of carbon neutrality for 2050, the four largest economic powers in the world will be in step with science and show the way towards a secure, clean and modern future", for his part commented Pr Johan Rockström, co-director of the Potsdam Institute for Climate Impact Research (PIK).

It will still be necessary to move from words to deeds, whether in Brussels, Beijing, Tokyo or Washington.

“Make no mistake about it. The grim reality is that while every state meets its commitments under the Paris Agreement (and many, which the US and EU today fall short of) , this will take us less than half the way "to limit the warming to + 2 ° C, warned on Twitter the climatologist Michael Mann, of Pennsylvania State University," cautiously optimistic "after the victory of Joe Biden.

>> READ ALSO -

Climate: Biden commits to joining the Paris agreement on the first day of his presidency

Reforms that also depend on the Senate

The room for maneuver of the future American president will depend in particular on his ability to pass ambitious climate legislation.

And to do this he will need the Senate, which could remain in Republicans' hands.

It will be necessary to wait for January 5, date of the second round of a senatorial in Georgia, to find out.

Without a majority in the Senate, Joe Biden will always be able to count on the thousands of non-federal entities (states, cities, companies ...) whose commitment in recent years should allow the United States to meet its old commitments despite everything. under the Paris Agreement (26 to 28% reduction in emissions by 2025 compared to 2005), according to Climate Action Tracker.

One month away from the 5th anniversary of the Paris Agreement, climate advocates are in any case hoping for a return of American leadership on the global climate scene.

"By returning from his first day in the Paris Agreement, President-elect Biden can stimulate confidence in international cooperation," said Andrew Steer. "Generations to come will remember the Biden-Harris administration as one that disappointed high expectations, or as one that truly served the American people, and the world," summed up Ottmar Edenhofer, another co-director of the PIK.