Climate Tipping Points, Ecological Collapse Could Arrive Sooner Than Expected: Study

A new study released Thursday warns that international experts may have been overly cautious in their warnings about widespread ecological collapse such as a catastrophic breakdown in the Amazon rainforest, which the Intergovernmental Panel on Climate Change said last year could come by the year 2100.

Scientists at Rothamsted Research and Southampton, Sheffield, and Bangor Universities in the United Kingdom found that as numerous factors such as water stress and pollution from mining compound the degradation of ecosystems in forests and bodies of water, the environments can be pushed toward tipping points more quickly.

The IPCC, suggests the study, which was published in Nature Sustainability, has been issuing its warnings about a tipping point in the Amazon while focusing on just a single factor, such as deforestation or planetary heating. Both of those drivers could interact with other environmental changes and accelerate tipping points such as dieback—in which the rainforest ecosystem would be replaced by one resembling a dry savanna.

"It is not clear whether the IPCC estimate for a tipping point in the Amazon forest before 2100 includes the possibility for interacting drivers and/or noise; if not, our findings suggest that a breakdown may occur several decades earlier," reads the report. "This would occur where local-scale failures in elements (such as species populations, fish stocks, crop yields, and water resources) combine with more extreme events (such as wildfires and droughts) to precondition the large-scale system, already vulnerable to the influence of other large-scale tipping elements, to collapse earlier—a meeting of top-down and bottom-up forces."

The researchers used computer models to assess the potential fates of two lake ecosystems and two forests, allowing for 70,000 adjustments of variables.

In the study, up to 15% of ecological collapses occurred as the result of new events or environmental stressors, even in cases where the primary stress affecting the ecosystem remained at the same level.

At Lake Erhai in southern China, for example, "abrupt lake eutrophication [the presence of excessive nutrients or minerals] was initially perceived to have been driven by transgression of a threshold in nutrient enrichment driven by agricultural runoff but historical analysis has shown that the shift was also affected by lake water-level management, seasonal climate, and fish farming," reads the study.

Because international experts may not have been considering variables such as water resources when they warned that the Amazon is headed for a climate tipping point by the turn of the next century, study co-author Professor Simon Willcock of Rothamsted Research told The Guardian, "We could realistically be the last generation to see the Amazon."

"It could happen very soon," he added.

The scientists said their research shows that even if some aspects of an ecosystem are managed sustainably, preventing stresses including planetary heating and extreme weather events—both being driven by the continued extraction of fossil fuels—is crucial for avoiding tipping points.

"Urgent action is needed now more than ever to prevent a catastrophic ecological collapse," said Tanya Steele, CEO of the World Wildlife Fund in the U.K., in response to the research.

Willcock noted that the study's findings suggest that an accelerated recovery of ecosystems is possible with a multi-pronged approach that would address deforestation, planetary heating, and other stresses.

"Potentially if you apply positive pressure," Willcock told The Guardian, "you can see rapid recovery,"