Widespread lockdowns made little dent in pollution rates, which have now returned from a temporary dip to above pre-pandemic levels, the United Nations has confirmed as it warned the world is "heading in the wrong direction".
Emissions of carbon dioxide during the first five months of this year were 1.2% higher than in the same period in 2019, "driven by increases in the United States, India and most European countries", according to preliminary data.
Measurements from all corners of the world, from Hawaii to Tasmania, show levels of the climate-heating gas in the atmosphere creeping up through 2021 and 2022, the collaborative report from a host of UN weather and climate agencies said.
Although countries' climate action plans are inching towards more ambitious action, the targets must still be seven times more ambitious to keep the world in line with the internationally agreed warming limit of 1.5C above pre-industrial levels.
This annual United in Science report shows climate impacts are "heading into uncharted territories of destruction", UN secretary-general António Guterres said.
The document, which summarises the latest climate science and action, arrives at the end of a painfully hot and turbulent summer for much of the northern hemisphere.
"There is nothing natural about the new scale of these disasters," said Mr Guterres. "They are the price of humanity's fossil fuel addiction."
Floods, droughts, heatwaves, extreme storms and wildfires are "going from bad to worse, breaking records with alarming frequency," he added.
There are now five times the number of weather-related disasters than 50 years ago, inflicting costs of £173m every day.
By the 2050s more than 1.6 billion people living in hundreds of cities, including Berlin, Lima and Seoul, will be regularly exposed to average temperatures of at least 35°C (95°F) during a three-month stretch, a 2018 study found. These people will be hit socially and financially, the UN's bleak assessment warns.
Climate scientists are "increasingly able to show that many of the extreme weather events that we are experiencing have become more likely and more intense due to human-induced climate change. We have seen this repeatedly this year, with tragic effect," Professor Petteri Taalas, secretary general of the World Meteorological Organization, said.
Climate breakdown made the UK's record-breaking heatwave 10 times more likely, experts concluded in July.
'Renewable energy revolution'
The UN report offers a few rays of hope, however.
Emissions of carbon dioxide from burning fossil fuels fell "significantly" in 23 countries, including many in the United States, Japan and many in Europe, in the decade before the pandemic.
Mr Guterres called for a "renewable energy revolution to bring down carbon emissions".
Sepi Golzari-Munro, energy transition director at the Global Wind Energy Council, said another "cause for renewed optimism" was the "unprecedented growth in renewable power... offering affordable, secure and clean energy".
Last year brought record-breaking offshore wind and solar PV deployment, and 2022 is on course to break those records again.
Further grounds for hope, she said, include the US passing $369bn of investment in climate measures, the biggest in its history, and the "greenslide" election in Australia, when voters kicked out a pro-coal government in favour of candidates that support tougher climate action.