JOIN USThe climate pledges of the world's top emitters
Under the Paris Agreement on climate, nearly every country will have to drastically reduce their carbon emissions, and they were supposed to submit renewed plans to do so by the end of 2020.
The first draft of "nationally determined contributions" (NDCs) submitted in 2015 would put Earth on course to be at least 3 degrees Celsius hotter than pre-industrial times, a far cry from the Paris temperature cap goal of keeping warming "well below" 2C.
Under the deal's "ratchet" mechanism, signatories are required to periodically renew their emission-cutting plans to drive more rapid decreases in emissions.
Roughly half of the countries met the 2020 deadline to do so, but many big emitters -- included the top two, China and the United States -- have yet to do so. Washington has said it will unveil its new targets this week, in anticipation of the delayed COP26 summit in Glasgow in November.
In its first NDC, China -- by far the largest emitter, responsible for roughly a quarter of all carbon pollution -- promised to reduce the intensity of its emissions by as much as 65 percent by 2030.
Under that scenario, it planned to reach peak emissions at the end of this decade.
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In September last year, President Xi Jinping made a surprise announcement at the UN General Assembly: China plans to achieve net-zero emissions by 2060.
But the country's new five-year plan, released in March, doesn't spell out the steps to reaching this goal, nor has Beijing officially submitted its renewed NDC.
The second-largest polluter, the US was one of the driving forces behind the Paris deal, with an initial commitment to cut emissions a quarter by 2025, compared with 2005 levels.
President Joe Biden wasted no time in office in rejoining the accord after his predecessor Donald Trump's decision to backtrack on US commitments.
He has set a net-zero date for 2050 and has unveiled a $2 trillion infrastructure spending plan to help achieve it.
The US has still not submitted its renewed NDC, but it is expected to do so either before or during a two-day climate summit this week.
The EU committed in 2015 to reduce its CO2 emissions by at least 40 per cent by 2030 compared to 1990 levels.
Member states updated this goal in December, aiming to reduce emissions by "at least 55 per cent" by the end of this decade.
Although Britain is leaving the EU, it also has a 2050 net-zero target built into law. It announced in December it would seek to reduce emissions 68 per cent by 2030, compared with 1990 levels.
Like China, India plans to reduce its carbon intensity -- by up to 35 per cent this decade compared to 2005 levels.
The world's third-largest polluter has yet to submit a renewed NDC.
Russia formally rejoined the Paris deal in 2019.
Moscow says it plans to achieve pollution levels in 2030 that are 70 per cent of 1990 levels -- in reality a drop of only 30 per cent.
Japan in 2016 committed to a 26-per cent reduction in emissions by 2030. Its renewed NDC, issued in March 2020, had the same figure, eliciting sharp criticism from carbon monitoring research groups.
However new Prime Minister Yoshihide Suga said in October the country would be carbon neutral by 2050.
Among other principal emitters, Brazil, Mexico, Australia and South Korea have all submitted their renewed NDCs, albeit without any significant boost in emissions cuts.
Indonesia, Canada, Saudi Arabia and South Africa have yet to submit their plans for the next five years.
Around 80 nations representing less than 30 per cent of emissions met the official deadline for NDC resubmissions.
The UN said that the renewed pledges would see emissions drop less than one per cent compared with 1990 levels -- a far cry from the 45-per cent cut that the UN's climate panel says is needed to limit warming to 1.5C.
More and more countries are committing to achieve net-zero emissions -- that is, any remaining carbon pollution will be sequestered or offset -- by 2050.
But according to the United Nations, more than 100 countries representing 65 per cent of global emissions have yet to formally set a date by which they must achieve climate neutrality.