Scientists detect a sudden acceleration in global warming

 Global warming has been increasing at a faster pace since about 2015, according to a new study from the Potsdam Institute for Climate Impact Research (PIK). By adjusting global temperature records to remove known natural influences, researchers were able to identify a statistically significant rise in the rate of warming for the first time.

During the past decade, global temperatures have climbed at an estimated rate of about 0.35°C per decade, depending on the dataset analyzed. From 1970 through 2015, the average increase was just under 0.2°C per decade. The more recent trend represents the fastest warming observed in any decade since instrumental temperature records began in 1880.

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

"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," Foster added.

Removing Natural Climate Variability From Temperature Data

Short term natural events can temporarily raise or lower global temperatures and make it harder to detect changes in long term climate trends. These influences include El Niño events, volcanic eruptions, and variations in solar activity.

To address this challenge, the researchers analyzed measurement data from five widely used global temperature datasets (NASA, NOAA, HadCRUT, Berkeley Earth, ERA5). By adjusting the data to account for these natural factors, the team was able to isolate the underlying warming trend more clearly.

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

Statistical Analysis Reveals a Shift in Warming Trends

The study focused on determining whether the pace of warming has changed, rather than identifying the causes behind that shift.

After accounting for the influence of El Niño and the recent solar maximum, the extremely warm years of 2023 and 2024 appear slightly cooler in the adjusted analysis. Even with these corrections, they still rank as the two warmest years recorded since instrumental measurements began. Across all datasets, the faster warming trend becomes visible around 2013 or 2014.

To evaluate whether the warming rate has changed since the 1970s, the researchers applied two statistical techniques: a quadratic trend analysis and a piecewise linear model that identifies when shifts in warming rates occur.

Implications for the Paris Agreement Climate Target

The study does not attempt to determine the specific reasons behind the acceleration in warming. However, the authors note that climate models already allow for the possibility that the rate of warming could increase over time.

"If the warming rate of the past 10 years continues, it would lead to a long-term exceedance of the 1.5°C limit of the Paris Agreement before 2030," says Stefan Rahmstorf. "How quickly the Earth continues to warm ultimately depends on how rapidly we reduce global CO2 emissions from fossil fuels to zero."

Source: ScienceDaily