Worst-case predictions ruled out by new climate change model

18 Jan 2018

Image: MrPhotoMania/Shutterstock

New research into climate change prediction models has cast serious doubt on existing belief.

One of the greatest challenges with climate change science is trying to predict, with complete accuracy, what is going to happen not only in the next few years, but the next few decades.

However, a team from the University of Exeter believes that its newly published research not only reduces much of the uncertainty that comes with predictive models, but also shows hope that we can turn things around.

While the majority agreement for the past 25 years has been that the range of climate sensitivity has remained between 1.5C and 4.5C, the new study actually reduces the variation by 60pc.

This narrows the range of potential global warming from 3C to 1.2C, which, if true, would have major implications for existing and future climate change agreements.

By dramatically reducing the range of climate sensitivity, the team said, scientists will be able to have a much more accurate picture of long-term changes to Earth’s climate.

“You can think of global warming as the stretching of a spring as we hang weights from it, and climate sensitivity as related to the strength of the spring,” explained the study’s lead author, Prof Peter Cox.

“To relate the observed global warming to climate sensitivity, you need to know the amount of weight being added to the spring, which climate scientists call the ‘forcing’, and also how quickly the spring responds to added weight. Unfortunately, we know neither of these things very well.”

We still need action

The breakthrough came after the team decided to move the focus away from following global warming trends to date, and instead looking at the variations in yearly global temperatures. This, the team added, means year-to-year variations can tell us a lot about longer-term changes we can expect in a physical system such as Earth’s climate.

Co-author of the study, Mark Williamson, said: “We used the simplest model of how the global temperature varies, to derive an equation relating the timescale and size of the fluctuations in global temperature to the climate sensitivity. We were delighted to find that the most complex climate models fitted around that theoretical line.”

As to how significant these results are for the future of climate science, Cox believes it gives us greater hope that we can reverse climate change’s most damaging effects.

“Our study all but rules out very low or very high climate sensitivities, so we now know much better what we need to [do],” he said. “Climate sensitivity is high enough to demand action, but not so high that it is too late to avoid dangerous global climate change.”

Colm Gorey was a senior journalist with Silicon Republic