The global implications would be profound. The loss of the rainforest would cause a large-scale drying across the region. The circulation of the atmosphere could change in response, altering weather patterns around the world.
How long it can keep holding on is the million-dollar question. The new study shows that an irreversible tipping point is inching closer — but it hasn’t arrived. And it’s still unclear how long it might take to get there.
As the forest begins to die off, it may enter a reinforcing cycle. With fewer trees, the region will grow even drier. More droughts will cause more trees to die. Wildfires may also grow more severe, wiping out huge tracts of forest at a time.
“Once it starts, my sense is it could happen in decades,” said Chris Boulton, a scientist at the University of Exeter and lead author of the new study.
‘There is still hope’
Scientists have warned, for instance, that the Greenland and Antarctic ice sheets may have their own dangerous thresholds — that enough future warming could cause rapid, unstoppable ice loss and the risk of catastrophic ice sheet collapse. In such a scenario, the effects on global sea levels would be apocalyptic.
Studies have also suggested that one of the world’s largest ocean currents, the Atlantic Meridional Overturning Circulation, is slowing down as the planet warms. The AMOC helps ferry heat between the equator and the Arctic and plays an important role in regulating climate and weather patterns throughout the Northern Hemisphere. Some experts have warned that the current may also have a tipping point, beyond which it could collapse entirely.
A recent report from the Intergovernmental Panel on Climate Change notes that there’s a lot of uncertainty about the Earth’s tipping points and a lot of debate about how much warming it would take to actually cross them (Climatewire, Aug. 12, 2021). While none of these scenarios can be completely ruled out, some of them present more immediate concerns than others.
Scientists generally agree that the ice sheets will likely melt at faster and faster rates in the coming decades, a growing concern for global sea-level rise. But catastrophic ice sheet collapse is highly unlikely anytime within the next 100 years. Similarly, the AMOC is expected to keep on slowing, but is unlikely to be at risk of collapse in this century.
The new study doesn’t make any concrete predictions about it.
“We can’t turn this into a definitive forecast of when the tipping would happen,” Lenton said.
Curbing global climate change is key. Slowing down the warming can help mitigate the droughts, wildfires and other disasters that are damaging the rainforest.
“The resilience loss that we observed means that we have likely moved closer to that critical point, to that tipping point,” said Niklas Boers, a modeling scientist at the Technical University of Munich and another co-author of the new study. “It also suggests we haven’t crossed that tipping point yet, so there is still hope.”
Reprinted from E&E News with permission from POLITICO, LLC. Copyright 2022. E&E News provides essential news for energy and environment professionals.
