The European Union's climate monitoring service has raised the alarm over sharp increases in record concentrations of methane in the atmosphere.
The last seven years have been the hottest on record globally "by a clear margin", the European Union's climate monitoring service has reported.
Globally, 2021 was the fifth hottest year on record, with an average temperature 1.1-1.2 degrees Celsius above 1850-1900 levels, the EU's Copernicus Climate Change Service (C3S) said in a report on Monday.
Accurate measurements go back to the mid-19th century.
Global levels of planet-warming carbon dioxide (CO2) and methane, the main greenhouse gases, in the atmosphere hit record highs last year, C3S said in its latest annual assessment.
As greenhouse gas emissions change the planet's climate, the long-term warming trend continued and record-shattering extreme weather swept the world in 2021.
From floods in Europe, China and South Sudan, to wildfires in Siberia and the United States, 2021 was one of the worst years for natural disasters.
"These events are a stark reminder of the need to change our ways, take decisive and effective steps toward a sustainable society and work towards reducing net carbon emissions," C3S director Carlo Buontempo said.
'A punch in the face'
C3S said levels of methane, a particularly potent greenhouse gas, have jumped in the last two years, but the reasons why are not fully understood.
Emissions of methane range from oil and gas production and farming to natural sources like wetlands.
At the COP26 climate summit last year, around a hundred nations joined an initiative to cut methane emissions by at least 30 percent this decade.
While global warming may seem gradual, its impact on extreme events is "dramatic", said Rowan Sutton, of Britain's National Centre for Atmospheric Science at Reading University.
"We should see the record-breaking 2021 events, such as the heatwave in Canada and floods in Germany, as a punch in the face to make politicians and public alike wake up to the urgency of the climate emergency," he told the Science Media Centre.