Absolutely certain that global warming has accelerated in past decade: Study

Over the past ten years, the estimated warming rate has been around 0.35°C per decade, depending on the dataset, compared with just under 0.2°C per decade on average from 1970 to 2015

Global warming has accelerated in the past ten years with a new study concluding it with 98% certainty. While scientists had started noting signs of rapid acceleration of warming in recent years, this is the first study to say it with scientific confidence.

This recent rate is higher than in any previous decade since the beginning of instrumental records in 1880. (Bloomberg photo)

After accounting for known natural influences like El Niño events, volcanic eruptions and solar variations on global temperature, the research team detected a statistically significant acceleration of the warming trend.

Over the past ten years, the estimated warming rate has been around 0.35°C per decade, depending on the dataset, compared with just under 0.2°C per decade on average from 1970 to 2015, the Potsdam Institute for Climate Impact Research (PIK) said on Friday evening.

This recent rate is higher than in any previous decade since the beginning of instrumental records in 1880, the authors emphasised.

HT reported on January 15 that global temperatures over the past three years (2023-25) averaged more than 1.5 degrees Celsius (C) above pre-industrial levels, marking the first three year period which has exceeded the threshold, Copernicus Climate Change Service (C3S) said.

Berkeley Earth, which focuses on land temperature data analysis has warned that the warming spike in 2023 to 2025 appears to have deviated significantly from the previous largely linear trend. The warming spike in 2023 to 2025 appears to have deviated significantly from the previous trend. If we were to assume that global warming was continuing at the same rate as during the 50-year period 1970-2019, then the 2023 to 2025 excursion would be by far the largest deviation from that trend, Berkeley Earth said.

“We can now demonstrate a strong and statistically significant acceleration of global warming since around 2015,” said Grant Foster, a US statistics expert and co-author of the study, which was published in Geophysical Research Letters.

Most importantly, the study has also concluded that if the warming rate of the past 10

years continues, the Paris Agreement 1.5°C warming limit will be breached by 2030.

“Stopping this trend is in our hands: studies show that global warming will stop around the time humanity reaches zero CO2 emissions, but it can hardly be reversed. In the current political climate, however, it is quite possible that warming may continue its fast pace or even accelerate further. This much is clear: if the warming rate of the past 10 years continues, the Paris Agreement 1.5°C warming limit will be breached by 2030,” the study states.

Short-term natural fluctuations in global temperature caused by El Niño, volcanic eruptions, and solar cycles can mask changes in the long-term rate of warming. In their data analysis, which is based on measurement data, the two researchers work with five large, established global temperature data sets (NASA, NOAA, HadCRUT, Berkeley Earth, ERA5).

“The adjusted data show an acceleration of global warming since 2015 with a statistical certainty of over 98%, consistent across all data sets examined and independent of the analysis method chosen,” explained Stefan Rahmstorf, PIK researcher and lead author of the study.

The study comes at a time when there is major disruption in climate action.

HT reported in January that the US withdrew from 66 international organisations and conventions on Wednesday, with its most significant exit from the United Nations Framework Convention on Climate Change (UNFCCC), likely to deal a crippling blow to global efforts to tackle the climate crisis. Further, on February 12, the Environmental Protection Agency rescinded its “endangerment finding” for greenhouse gases. The 2009 “endangerment finding” concluded that a range of greenhouse gases were a threat to public health. Now, the Iran conflict is also a distraction from urgent efforts to curb emissions experts have noted.

“Along with its brutal human costs, this newest upheaval shows yet again that fossil fuel dependence leaves economies, businesses, markets and people at the mercy of each new conflict or trade policy lurch. But there is a clear solution to this fossil fuel cost chaos - renewables are now cheaper, safer and faster-to-market, making them the obvious pathway to energy security and sovereignty,” Simon Stiell, Executive Secretary of UN Climate Change had said last week.

“How quickly the Earth continues to warm ultimately depends on how rapidly we reduce global CO₂ emissions from fossil fuels to zero,” said Stefan Rahmstorf in a statement.