The planet is getting warmer, but at a statistically steady rate, a new study reveals. An international team of researchers from the U.S. and U.K. investigated if the rate of global warming has significantly increased, or “surged,” over the last half-century at statistically detectable rates. Published in Nature Communications Earth & Environment, the study confirms the broad consensus that the planet is getting warmer, but not at a sufficiently accelerated rate that can be statistically defined as a “surge.” Recent years have seen record-breaking temperatures and heat waves globally.
Data show 2023 was the warmest year since global records began in 1850. The 10 warmest years in the historical record have all occurred in the past decade (2014-2023). The team’s findings demonstrate a lack of statistical evidence for an increased warming rate that could be defined as a “surge.” Using detailed analyses of the global temperature anomaly series, they detected the well-documented temperature increase that started in the 1970s but found no significant changes in the rate of global warming after that period.
“Of course, it is still possible that an acceleration in global warming is occurring,” said lead author Claudie Beaulieu, professor of ocean sciences at University of California Santa Cruz. “But we found that the magnitude of the acceleration is either statistically too small, or there isn’t enough data yet to robustly detect it.”
Researchers performed a rigorous analysis of global surface-temperature averages from the four main agencies that track the average temperature of Earth’s surface, including NASA and NOAA, dating back to 1850.
Study confirms steady global warming
Since then, Earth’s temperature has risen by 0.11 degrees Fahrenheit per decade, according to NOAA. The study analyzed the “global mean surface temperature” (GMST), which tends to rise due to human-caused pressures and fluctuates because of natural phenomena. Distinguishing between natural variability and true underlying changes in the pace of warming is a statistical challenge, the team acknowledged.
“A warming surge would be indicated by sustained observed temperatures well above those expected under the current warming scenario, and we wanted to give climatologists an idea of how many years it might take to statistically detect a surge or hiatus relative to the current estimated rate,” said Colin Gallagher, one of the researchers. The team determined the level of increased warming necessary for a given number of years to detect surges. They found that a warming surge, indicated by a statistically significant change in the rate of warming, has not been observed.
Beaulieu emphasized, “Earth is the warmest it has ever been since the start of the instrumental record because of human activities — and to be clear, our analysis demonstrates the ongoing warming. However, if there’s an acceleration in global warming, we can’t statistically detect it yet.”
Other co-authors on the paper include Robert Lund, professor and department chair of statistics at UC Santa Cruz, and Xueheng Shi, assistant professor of statistics at the University of Nebraska-Lincoln.
