The COVID crisis is child’s play compared to the impending climate change crisis that is coming fast and hard.
For a decade, her team had been sampling the air from sensors on aircraft flying over the world’s largest rainforest. Their collating of recent results showed that, perhaps for the first time in thousands of years, a large part of the Amazon had switched from absorbing carbon dioxide from the air, damping down global warming, to being a “source” of the greenhouse gas and thus speeding up warming.
“We have hit a tipping point,” Gatti almost shouted, caught between elation at her discovery and anguish at the consequences.
As she spoke, fires were burning across the Amazon, making headlines around the globe. But her findings were not the short-term result of the fires. They were based on measurements from before the upsurge in fires, and showed a long-term trend. She had previously observed the same thing briefly during drought years. But now it no longer mattered if it was a wet or a dry year, or how many fires there were, the sink had become a source. “Each year it gets worse,” she said. “We have to stop deforestation while we work out what to do.”
Gatti asked me to keep silent for the time being, while she prepared her data for publication. When I contacted her this month, her paper was still being finalized. But I can now tell the story. It vividly illustrates a growing dismay among climate scientists, who are seeing ecosystems around the world going the way of the Amazon.
The scientists are warning that past climate models used by the UN’s Intergovernmental Panel on Climate Change (IPCC) have not fully reflected the scale of the warming that lies ahead as carbon sinks die. These revelations are coming from three areas of research: Studies such as Gatti’s in the Amazon, showing forests turning from sinks to sources of carbon dioxide; a new generation of climate models that incorporate these findings into future projections of climate change, and whose early outputs are just emerging; and recent revelations that ecosystems are releasing rising volumes of methane—the second-most important greenhouse gas and of vital importance for temperatures in the next couple of decades.
It’s 5:00 somewhere.