Nicholas School researchers discredit belief that global temperatures will vary more in future

Global temperatures might be more predictable in the future, but only for some places, according to a Duke study.

The team of scientists, including Wenhong Li, associate professor of climate at the Nicholas School of the Environment, and Patrick Brown, Nicholas '16, found in a series of simulations that global temperatures will begin to fluctuate less within the coming decades. Their conclusions challenge the popular notion that climate change will lead to an increase in variable temperature globally. 

“It’s something I’ve noticed in public discourse related to global warming, that everything will become more variable, everything will become more crazy, but that’s not what we expect in reality,” Brown said.

One implication of this predicted decrease in temperature variability is that global temperature will be more predictable from decade to decade, he explained. Brown added that temperature variability is often compared to the carbon dioxide curve, since variations in temperature mimic variations in global carbon dioxide levels.

“As time goes on, and temperature variability decreases, we would expect the temperature to follow the carbon dioxide curve closer," he said. 

Brown explained that their findings were linked to ice distributions across the globe—especially those at higher altitudes. Normally, as ice melts, it absorbs some solar energy, thus amplifying the effects of climate change on temperature. However, in the future, atmospheric carbon dioxide concentrations may be so high that there may be too little ice for such an effect.

Irregular temperature events like surges—where the temperature is not correlated carbon dioxide levels, but instead increases because the system itself is warming—would become less frequent, Brown added.

He also stressed the importance of examining climate trends at the local level. The study demonstrated that although global temperature variability may decrease, in some smaller local areas, temperatures may begin to grow even more irregular.

The study showed that temperature variability could increase in areas such as Australia and the tropics, Brown explained, adding that these increases in local temperature variability could have severe negative impacts.

“I’m sure that ecologists that study the Amazon rainforest will tell you that it’s not a good thing to have an increase in temperature variability there, and that’s the type of thing this study is showing,” he said. “Even though the global average variability is decreasing, if it is locally increasing in certain key locations, that could have big implications.”

As for what such a future might look like, Brown noted that since he is not a climatologist, he could only speculate to what might happen in the future.

“I don’t study public policy or ecology, but I imagine it would be harder to manage water systems and agriculture and irrigation," he said. "It all takes knowledge of what the current climate is, and if the current climate is more variable, it’s harder to deal with that.” 


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