Global weather in the calendar year 2023 shattered many records and was likely the warmest in 100,000 years globally, scientists at the European Centre for Medium Range Weather (ECMRF) Copernicus Climate Change Service.
The trend in the warm weather will likely continue in the first quarter of 2024 due to El Nino, which is set to end by June.
“2023 was an exceptional year with climate records tumbling like dominoes. Not only is 2023 the warmest year on record, it is also the first year with all days over 1°C warmer than the pre-industrial period.
“Temperatures during 2023 likely exceed those of any period in at least the last 100,000 years,” said Samantha Burgess, Deputy Director of the Copernicus Climate Change Service (C3S).
The main drivers behind 2023 being confirmed the warmest year on record with regard to temperature records dating back to 1850 were greenhouse gas concentrations, El Niño and other natural variations.
C3S has made this conclusion based on various scales such as centennial and millennial and looking at coral reefs below the sea.
Impact on India
“... by far the biggest factor was the ever-increasing amount of greenhouse gases in the atmosphere that trap heat. Those gases come from the burning of coal, oil and natural gas,” said Burgess.
The climate change impacted India with the South-West monsoon being deficient and the country going through its driest August in 120 years. The North-East Monsoon has also been affected, while January has received far more than normal levels.
As a result, kharif agricultural production has been estimated over 3 per cent lower, while the standing rabi crops face problems due to non-availability of water, particularly in the South.
Carlo Buontempo, Director, C3S , ECMWF, said El Niño alone does not explain all of the increase in ocean surface temperatures at a global scale in 2023, as high sea surface temperatures (SSTs) outside of the equatorial Pacific contributed significantly to the record-breaking global SSTs.
Several influential factors
Marine heatwaves were a common occurrence in 2023, affecting regions such as the Mediterranean, the Gulf of Mexico and the Caribbean, the Indian Ocean and the North Pacific, and much of the North Atlantic, said Burgess.
“On longer timescales, several factors may have also influenced or reinforced the warm anomalies including heat content coming from deeper ocean levels,” she said.
According to Copernicus global climate highlights of 2023, the year witnessed a global average temperature of 14.98°C, up 0.17°C than the previous highest annual value in 2016. It was 0.60°C warmer than the 1991-2020 average and 1.48°C warmer than the 1850-1900 pre-industrial level.
“2023 marks the first time on record that every day within a year has exceeded 1°C above the 1850-1900 pre-industrial level. Close to 50 per cent of days were more than 1.5°C warmer than the 1850-1900 level, and two days in November were, for the first time, more than 2°C warmer,” said Francesca Guglielmo, Senior Scientist, C3S, ECMWF.
Large number of extremes
Each month from June to December in 2023 was warmer than the corresponding month in any previous year. July and August were the warmest two months on record. Boreal summer (June-August) was also the warmest season on record, she said.
September 2023 was the month with a temperature deviation above the 1991–2020 average, larger than any month in its dataset, while December 2023 was the warmest December on record globally. The average temperature was 13.51°C, 0.85°C above the 1991-2020 average. It was 1.78°C above the 1850-1900 level for the month, said Guglielmo.
In 2023, a large number of extreme events were recorded across the globe, including heatwaves, floods, droughts and wildfires. “The estimated global wildfire carbon emissions in 2023 increased by 30 per cent with respect to 2022 driven largely by persistent wildfires in Canada,” she said.
Earliest signs in June
“The earliest signs of how unusual 2023 was to become began to emerge in early June, when temperature anomalies relative to 1850-1900 pre-industrial level reached 1.5°C for several days in a row,” said Carlo Buontempo, Director, C3S, ECMWF.
Though this was not the first time daily anomalies had reached this level, this had never previously happened at this time of the year, he said.
The C3S scientist said January and February 2024 will also experience “abnormally warm temperatures” due to El Nino. “Global ocean temperatures were higher than before in 2023. We expect the trend seen in late 2023 to continue at least until March before El Nino begins to dissipate,” said Burgess.
Buontempo said there would be rapid transition of El Nino to neutral by Spring, but it is too early to say if La Nina, which leads to rains and floods in Asia, will emerge.
“We are uncertain how the ocean temperatures will continue to evolve in 2024,” said Burgess.