News ID: 217507
Published: 0551 GMT June 30, 2018

Climate models fail to account for CO₂'s impact on life

Climate models fail to account for CO₂'s impact on life
Research suggested planet Earth's biological systems, including rates of vegetation growth, could be altered by rising CO₂ levels even as warming slows.

Increasingly, climate scientists are calling for climate models to focus more on CO₂ levels and less on temperature.

In a new study, researchers from the University of Exeter in England contend warming could slow even as a rise in CO₂ accelerates. Not only do current models mostly ignore this reality, study authors suggest they also fail to account for CO₂'s myriad impacts on biology — on life, UPI reported.

Because current models use too narrow a range to describe future CO₂ concentration, predictions tend to ignore the gas' impact on plants and animals.

Exeter researcher Richard Betts said, "Higher CO₂ concentrations cause increased growth in many plant species.

"This causes a general 'greening' of vegetation, but also changes the makeup of ecosystems — some species do better than others. Slower-growing large tree species can lose out to faster-growing competitors."

Higher CO₂ levels can also cause plants to use less water, which can diminish the impact of droughts on local ecosystems.

Betts said, "Both of these factors can potentially enhance crop yields, possibly helping to offset some of the negative impacts of climate change —although even if that happens, the nutritional value of the crops can be reduced as a result of the extra CO₂.

"Rising CO₂ also causes ocean acidification which is damaging to corals and some species of plankton."

The new research doesn't diminish the threat of global warming. Recent studies have suggested rising CO₂ levels could pose a variety of serious threats even if warming rates plateau.

The latest paper — published in the journal Nature Climate Change —suggested the impacts of rising CO₂ levels are likely to prove a mixed-bag.

But the details buried in that mixed-bag won't be revealed unless climate scientists start paying closer attention to the impact of rising CO₂ levels on biological systems.

Betts said, "To get the full picture, we need to consider these other effects of CO₂ as well as those of rising temperatures.”

Betts and his research partners didn't attempt to predict the impacts of different CO₂ levels on biological processes. Their aim was to show a wider variety of CO₂ levels are compatible with different warming scenarios.

Betts added, "Instead of calculating the probability of a particular amount of warming if CO₂ doubles, we calculated the probability of a particular amount of CO₂ rise for a particular level of warming.

"This lets us estimate what the range of CO₂ concentrations would be when global warming passes those levels, if CO₂ were the only thing in the atmosphere that we are changing."


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