New Delhi, March 9 Global warming has accelerated significantly since 2015, according to a study that accounts for natural fluctuations in the warming rate and the influence of El Niño events, volcanic eruptions, and variations in the solar cycle on temperature data.
Researchers, including those from the Potsdam Institute for Climate Impact Research in Germany, said that 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.
The study, published in the journal Geophysical Research Letters, analyzed five global temperature datasets, including those managed by NASA and the National Oceanic and Atmospheric Administration (NOAA).
"We filter out known natural influences in the observational data, so that the 'noise' is reduced, making the underlying long-term warming signal more clearly visible," said Grant Foster, a US statistics expert, who is a co-author of the study.
"The resulting adjusted and thus less "noisy" data show that there has been acceleration with over 98 per cent confidence, with faster warming in (more than) the last 10 years than during any previous decade," the authors wrote.
Statistical confidence is the chance that a specific statistical method will correctly capture the true population value upon repeated sampling.
Subtracting the estimated influence of El Niño events, volcanic eruptions, and solar variations from the datasets makes the global temperature curve less variable, which "then shows a statistically significant acceleration of global warming since about the year 2015," the team said.
They also found that the years 2023 and 2024, which were exceptionally warm, become somewhat cooler, but remain the two warmest years since the beginning of instrumental records.
They added that while accelerated warming is not unexpected, it is a cause for concern and shows that efforts directed at slowing and eventually stopping global warming under the Paris Agreement have so far been insufficient.
"If the warming rate of the past 10 years continues, it would lead to a long-term exceedance of the 1.5 degrees Celsius limit of the Paris Agreement before 2030," said Stefan Rahmstorf, a researcher at the Potsdam Institute for Climate Impact Research, who is the lead author of the study.
"How quickly the Earth continues to warm ultimately depends on how rapidly we reduce global (carbon dioxide) emissions from fossil fuels to zero," Rahmstorf said.