An international team of researchers from the United States, United Kingdom, and Germany has found that positive feedback loops are actively exacerbating global climate change. In a paper(Opens in a new window) published in the journal One Earth, the researchers describe these loops as “a process whereby an initial change that causes warming brings about another change that results in even more warming,” Unfortunately, they had many of these to discuss in detail.
The team divided these feedback loops into physical and biological categories. A couple of the 11 physical positive feedback loops might sound familiar, like melting sea ice in the Arctic; when the ice melts, there’s less bright white ice and more dark water, which absorbs more heat. Lesser-known physical positive feedback loops on their list involved Antarctic rainfall, the ocean’s solubility pump, and ocean stratification.
(Credit: Joanne Francis/Unsplash)
A familiar positive feedback loop of the chemical variety involves increasingly prevalent wildfires. When organic material burns, it releases carbon dioxide into the air, which bolsters the greenhouse effect and causes the atmosphere to warm more rapidly. Warmer, drier conditions create even more fertile ground for wildfires, perpetuating that burn cycle. The researchers also touched on aquatic plant growth rates, forest dieback, microbial respiration rates, and other phenomena that feed climate change.
While they studied 41 total feedback loops (20 physical and 21 biological), a few were found to be neutral or indeterminate in nature, meaning they aren’t currently known to exacerbate climate change. Seven were even found to be negative, suggesting that they might help alleviate or slow climate change—but not enough to make up for the 27 positive feedback loops.
Because these feedback loops weren’t studied in detail until recently, they’re largely missing from existing climate models. This means our current projections likely underestimate how much our climate could warm in the coming years.
“In a likely short-term scenario, our lack of dramatic emission reductions could result in a future with ongoing and intensifying climate impacts,” the researchers write. “In the worst case long-term scenario, interactions among feedback loops could result in an irreversible drift away from the current state of Earth’s climate to a state that threatens habitability for humans and other life forms.”
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