Climate Change

Last 12 months were the warmest in 125,000 years

Temperatures 1.3°C above the pre-industrial era since November 2022

 
By Rohini Krishnamurthy
Published: Thursday 09 November 2023
Photo: iStock__

The last 12 months have been the warmest in the last 125,000 years, with temperatures reaching 1.32 degrees Celsius above the pre-industrial era, according to a new report.

During this time period, 90 per cent of people (7.3 billion) were affected by climate change by experiencing at least 10 days of temperatures “very strongly”, read the report by Climate Central, a nonprofit organisation that researches and reports climate science and impact.

“The fact that we set records this year in some way is not surprising,” Andrew Pershing, vice president of science at Climate Central, lead author of the analysis, said in a press briefing on November 8, 2023. “We should expect to set records because we live on a warming planet due to increasing carbon dioxide levels.”


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El Nino, Pershing explained, is really going to start to bite next year. “And so that’s going to lead to even more warming as we move on into 2024,” he noted. El Nino, a warm phase of a recurring climate pattern, set in on July 4, 2023, according to the World Meteorological Organization. Its intensity is currently moderate.

The report estimated that it is highly likely that temperatures over the next 12 months could exceed 1.4°C.

Pershing and his colleagues looked at the extent of climate change’s influence on warming by using observations, computer models, and statistical methods.

The team looked at what the expected distribution of temperatures would be in that environment with 1.3°C of warming. Next, they subtracted the influence of global warming by recreating what that distribution of temperatures would look like in a world without global warming. 

The team used their attribution system — the Climate Shift Index (CSI) — to map the influence of human-caused climate change on daily local temperatures and multi-day extreme heat events across the globe. 

The CSI value ranges from zero to five. A CSI value of zero means that there is no detectable influence of human-caused climate change while a CSI level of one suggests that climate change made the temperatures at least 1.5 times more likely. 


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CSI levels 2 and higher are multipliers of at least 2 times, 3, 4, and 5 times more likely. CSI Level 5 events indicate that such temperatures would be extremely unlikely without climate change.

The analysis found that from November 2022 to April 2023, 58 per cent of people were exposed to 10 or more days at a very strong CSI level of 3. This means that such temperatures were made at least three times more likely by climate change. 

In the last six months, the number of people exposed to 10 or more days at a very strong CSI level of three grew by 82 per cent.

In India, 86 per cent population was exposed to climate shift index levels of more than 3 for more than 30 days. The country recorded a mean CSI of one from November 2022 to October 2023.

Within India, Kerala, Goa, Andaman and Nicobar Islands, Puducherry, and Mizoram recorded the highest CSI levels of 3.6, 3.4, 3.3, 3.2 and 3, respectively. 

The small island developing states and least developing countries had high average CSI values of 2.7 and 2, respectively.


Read more: El Nino may remain till April 2024, may push temperatures even higher: WMO


Ten countries with the highest historical emissions had an average CSI of 0.7, while the 10 lowest emitters scored a CSI value of 2.7.

Among the G20 countries, nine— Saudi Arabia, Mexico, Indonesia, India, Italy, Japan, Brazil, France, and Turkey — experienced comparably significant climate-driven heat, the report highlighted.

Further, the World Weather Attribution, an academic collaboration studying extreme event attribution, looked at five heatwave events this year. These include early spring heat in South America, extreme heat in North America, Europe, and China in July 2023, extreme humid heat in South Asia in April 2023, extreme April heat in Spain, Portugal, Morocco, and Algeria, record-breaking early season heat in Argentina and Paraguay. 

“In all of these, we have found that there's a very strong climate change signal,” Friederike Otto, senior lecturer for climate science at the Grantham Institute for Climate Change and the Environment and co-lead of World Weather Attribution, said at the press briefing.

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