Although paperwork was originally filed by the Trump administration a year ago, the lengthy process to exit from the agreement has only been formally concluded today (Wednesday 4 November).

The move still leaves some 189 countries that remain committed to the 2015 Paris accord, with just eight nations that have not signed it.

Given that the US is the country that emits the most carbon per capita – and the second most-emitting country in the world after China – the withdrawal signalled a major blow to the agreement.

However, with the US election for 2020 underway and as-yet undecided, there is still a very real possibility that Democratic challenger Joe Biden, who has promised to re-join the agreement if he gains power, will clinch victory.

“The US withdrawal will leave a gap in our regime and the global efforts to achieve the goals and ambitions of the Paris Agreement,” said Patricia Espinosa, executive secretary of the UN Framework Convention on Climate Change (UNFCCC).

The United States still remains a party to the UNFCCC. Espinosa said the body will be “ready to assist the US in any effort in order to rejoin the Paris Agreement.”

Scientists say that any rise beyond 2°C – the maximum rise targeted by the agreement – could have a devastating impact on large parts of the world, raising sea levels, stoking tropical storms and worsening droughts and floods.

The Paris accord requires countries to set their own voluntary targets for reducing greenhouse gases such as carbon dioxide. The only binding requirement is that nations have to accurately report on their efforts.

Although Trump announced his intention to withdraw in June 2017, due to what he perceived as its negative economic impact, he was unable to formally do so until now because of the requirements of the deal.

In addition, many states that have historically predominantly leaned Democrat promised to adhere to the terms of the agreement, despite the federal effort to reject it.

On first signing the agreement, then-US president Barack Obama pledged to cut US emissions by 26-28 per cent by 2025 from 2005 levels.

Biden is broadly expected to ramp up those goals if elected. He has promised to achieve net-zero emissions by 2050 under a $2tr plan to transform the economy.

Although paperwork was originally filed by the Trump administration a year ago, the lengthy process to exit from the agreement has only been formally concluded today (Wednesday 4 November).

The move still leaves some 189 countries that remain committed to the 2015 Paris accord, with just eight nations that have not signed it.

Given that the US is the country that emits the most carbon per capita – and the second most-emitting country in the world after China – the withdrawal signalled a major blow to the agreement.

However, with the US election for 2020 underway and as-yet undecided, there is still a very real possibility that Democratic challenger Joe Biden, who has promised to re-join the agreement if he gains power, will clinch victory.

“The US withdrawal will leave a gap in our regime and the global efforts to achieve the goals and ambitions of the Paris Agreement,” said Patricia Espinosa, executive secretary of the UN Framework Convention on Climate Change (UNFCCC).

The United States still remains a party to the UNFCCC. Espinosa said the body will be “ready to assist the US in any effort in order to rejoin the Paris Agreement.”

Scientists say that any rise beyond 2°C – the maximum rise targeted by the agreement – could have a devastating impact on large parts of the world, raising sea levels, stoking tropical storms and worsening droughts and floods.

The Paris accord requires countries to set their own voluntary targets for reducing greenhouse gases such as carbon dioxide. The only binding requirement is that nations have to accurately report on their efforts.

Although Trump announced his intention to withdraw in June 2017, due to what he perceived as its negative economic impact, he was unable to formally do so until now because of the requirements of the deal.

In addition, many states that have historically predominantly leaned Democrat promised to adhere to the terms of the agreement, despite the federal effort to reject it.

On first signing the agreement, then-US president Barack Obama pledged to cut US emissions by 26-28 per cent by 2025 from 2005 levels.

Biden is broadly expected to ramp up those goals if elected. He has promised to achieve net-zero emissions by 2050 under a $2tr plan to transform the economy.