Relentless stretch of heat records in March unnerves climate scientists

Record sea temperatures over an unprecedented stretch and on land for the tenth month in a row have unnerved climate scientists, driving the global average temperature rise beyond 1.5C since pre-industrial times. 

Sea surface temperatures in March at 21.07C were the warmest on record for the 12th month in a row, Europe’s Earth observation agency said, confounding its climatologists.

“Myself and other climate scientists are asking whether this year is a blip, a phase change, whether the climate system is broken and behaving in a different way to what we expect,” said Samantha Burgess, deputy director of the Copernicus Climate Change Service.

Land temperatures in March were 14.14C, exceeding the previous high set in March 2016 by 0.1C. This was 1.68C above the pre-industrial average for the month of March, and for the 12 month period it surpassed the 1850 to 1900 average by 1.58C.

The long-term rise in average global temperatures of 1.5C that is set down as an ideal limit in the Paris Agreement is determined over decade-long periods which are yet to be observed.

But Burgess said that the jumps in daily temperatures were even higher than those anticipated by climate models.

These models are built using data on how changes to fossil fuel use producing greenhouse gases, as well as aerosols, volcanic eruptions, solar activity and Pacific Ocean currents, have each driven global warming in the past.

Temperatures have been rising even faster than would be expected from the scale of these influences today, including from energy systems. “The observational records are warmer than what the records told us the warming should be,” she said.

The data came as the latest analysis showed listed companies were on a pathway to warm the planet by 3C by the end of the century. Information provider MSCI said only 11 per cent of companies were aligned with a 1.5C temperature rise, in analysis based on the emissions goals and data of publicly listed companies in the MSCI ACWI index.

This is in line with findings by the UN environment programme last year. It said the world was on track for a temperature rise of up to 2.9C above pre-industrial levels, even assuming countries met their Paris accord pledges.  

Mark Maslin, professor of earth system science at University College London, said the continued trend of temperatures reaching more than 1.5C above pre-industrial levels was “deeply worrying”.

It was a level that had not been expected to be witnessed until later this decade by many scientists, he noted. “Things seem to be happening slightly faster [than expected].”

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Oceans had continued to warm despite the weakening of the ongoing and naturally occurring El Niño phenomenon, associated with a warming of the Pacific Ocean, Copernicus said.

El Niño has a 3 per cent chance of persisting until the May to July period, the US National Oceanic and Atmospheric Administration estimates. The reverse La Niña, which has a cooling effect, had a 32 per cent chance of occurring, rising to 85 per cent by the end of the year, it said.

Maslin noted that in regions less affected by Pacific circulation currents, such as the Mediterranean, temperatures were high “not [primarily] because of El Niño but because of climate change, because we’ve been dumping huge amounts of greenhouse gases into the atmosphere for the last 150 years.”

Each fraction of a degree of warming of the atmosphere contributes to more frequent and extreme weather events.

Temperatures in March were above average over eastern North America, Greenland, eastern Russia, southern Australia and parts of Africa and South America, Copernicus said.

The average European temperature for March was 2.12C above the 1991-2020 average for March, making the month the second warmest March for the continent, only a margin of 0.02°C less than the March 2014 record.

It was wetter than average in most of western Europe, with heavy rainfall over Portugal, France and Spain, as well as parts of North America, central Asia and much of the Arabian peninsula. In Australia, it was “exceptionally” wet.

Other parts of the world were drier than average, including western Canada, northern Mexico, some of central Asia, China and south-eastern Australia and South America.

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