US President Joe Biden is announcing a new target to cut greenhouse gas pollution in America by at least half by 2030, as he convenes a summit of world leaders aimed at driving greater climate action.

The US president’s new target aims to achieve a 50-52% reduction in emissions from 2005 levels by 2030.

The White House says the move will create millions of jobs, cut energy costs and boost nature.

Meanwhile, analysts have hailed the move, saying it is “major progress” on previous US commitments, and helps reduce the gap between the action needed to curb dangerous global warming and what countries have pledged to do – although it is not quite enough to bring America in line with achieving international climate goals.

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It comes at the start of a virtual climate summit convened by Mr Biden.

Boris Johnson will also tell fellow world leaders that 2021 must be the year countries “get serious” about stopping climate change.

The Prime Minister this week announced a “world-leading” target for the UK to cut emissions by 78% on 1990 levels by 2035, which builds on plans to cut pollution by 68% by 2030, the most ambitious among leading economies.

But campaigners in the UK have warned that policies and action are urgently needed to deliver on the pledges and cut pollution from homes, transport, industry and power supplies.

Mr Johnson is expected to tell the meeting: “The UK has shown that it’s possible to slash emissions while growing the economy, which makes the question of reaching net zero not so much technical as political.

“If we actually want to stop climate change, then this must be the year in which we get serious about doing so.

“Because the 2020s will be remembered either as the decade in which world leaders united to turn the tide, or as a failure.”

The summit comes after the International Energy Agency warned that global carbon emissions were set for their second biggest increase on record after a sharp drop in 2020 due to the pandemic, with demand for fossil fuels, including coal, pushing climate pollution up to close to 2019 levels.

The two-day US-led summit will also hear from leaders of major economies including China, Japan, Russia, Canada, India and Australia, who will be watched closely to see what ambition they will bring to the table.

Before the summit started, Japan unveiled a new, stronger 2030 target which aims to cut emissions by 46% on 2013 levels, up on its earlier goal of 26% reductions, to achieve carbon neutrality by 2050 as announced in October.

Japan’s prime minister Yoshihide Suga said Japan would further try to push the reduction as high as 50%.

The European Union has agreed a new climate law which includes a goal to cut its emissions by 55% by 2030 on 1990 levels.

As part of diplomatic efforts in the lead-up to the summit, the US and China issued a statement pledging to work together and with other countries on the issue.

The US reduction – estimated to be around a 41-44% cut on 1990 levels – is part of the US’s national climate plan, which it is submitting as part of its return to the Paris climate accord, the world’s first comprehensive climate treaty which Donald Trump quit when he was president.

Countries have been expected to come forward with more ambitious plans up to 2030, known as nationally determined contributions (NDC) in the Paris deal, ahead of Cop26 in November.

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That is because existing plans are not enough to meet countries’ commitments under the Paris deal to curb global temperature rises to “well below” 2C above pre-industrial levels – or 1.5C if possible – and avoid the most dangerous impacts of climate change.

Analysts at Climate Action Tracker said the new US target was a significant step forward and would reduce the global emissions gap between action pledged and the cuts needed to meet the Paris goals by around 5-10% in 2030.

But bigger cuts of 57-63% by 2030 would be needed for the US to play its part in meeting the 1.5C target and put the country on a better track to achieving its pledge to cut emissions to net zero by 2050.

The summit, which will have sessions on increasing climate action, finance for developing countries, the role of natural solutions such as restoring forests and peatlands, and security impacts of climate change, will also hear from United Nations secretary general Antonio Guterres and Pope Francis.