Researchers now argue that the warming slowdown was real
The latest salvo in an ongoing row over global-warming trends claims that warming has indeed slowed down this century.
An apparent slowing in the rise of global temperatures at the beginning of the twenty-first century, which is not explained by climate models, was referred to as a “hiatus” or a “pause” when first observed several years ago. Climate-change sceptics have used this as evidence that global warming has stopped. But in June last year, a study in Science claimed that the hiatus was just an artefact which vanishes when biases in temperature data are corrected.
Now a prominent group of researchers is countering that claim, arguing in Nature Climate Change that even after correcting these biases the slowdown was real.
“There is this mismatch between what the climate models are producing and what the observations are showing,” says lead author John Fyfe, a climate modeller at the Canadian Centre for Climate Modelling and Analysis in Victoria, British Columbia. “We can’t ignore it.”
Fyfe uses the term “slowdown” rather than “hiatus” and stresses that it does not in any way undermine global-warming theory.
Ups and downs
The debate revolves in part around statistics on temperature trends. The study that questioned the existence of the slowdown corrected known biases in the surface temperature record maintained by the US National Oceanic and Atmospheric Administration (NOAA), such as differences in temperature readings from ships and buoys. This effectively increased the warming recorded, and the researchers also extended the record to include 2014, which set a new record high for average temperatures.