NEWS

ECOLOGICAL "DOOM LOOPS" EDGING CLOSER ACCORDING TO NEW STUDY

Extreme events combined with rising stress levels are increasing the likelihood of ecosystem collapse

  • 22
  • JUN
  • 2023

Extreme weather events such as wildfires and droughts will accelerate change in stressed systems leading to quicker tipping points of ecological decline, according to a new study published today in Nature Sustainability.

Using computer modelling, the research team looked at four ecosystems under threat to work out what factors might lead to tipping points, beyond which collapse was inevitable. In some systems, the combination of adding new extreme events on top of other ongoing stresses brought the timing of a predicted tipping point closer to the present by as much as 80%.

Ultimately, say the authors, a “perfect storm” of continuous stress from factors such as unsustainable land use, agricultural expansion and climate change, when coupled with disruptive episodes like floods and fires, will act in concert to rapidly imperil natural systems.  

“Over a fifth of ecosystems worldwide are in danger of collapsing,” said Professor Simon Willcock, who co-led the study. “However, ongoing stresses and extreme events interact to accelerate rapid changes that may well be out of our control. Once these reach a tipping point, it’s too late.”

The team looked at two lake ecosystems and two forestry examples, including the historic collapse of the Easter Island (Rapa Nui) civilisation, widely thought to have been the result of over-population combined with unsustainable exploitation of tree cover.

The models were run over 70,000 times for each ecosystem, with variables adjusted on each occasion. Up to 15% of collapses occurred as a result of new stresses or extreme events, even while the main stress was kept constant.  In other words, even if ecosystems are managed more sustainably by keeping the main stress levels like deforestation constant, new stresses like global warming and extreme weather events could still bring forward a collapse.  

The number of extreme climate events has increased since 1980 and global warming even at 1.5°C will increase those numbers further.  Scientists are also concerned about possible knock-on effects as one collapsing ecosystem impacts on neighbouring ecosystems.

“In the past two years, the world has come together around the climate and ecological crises through the UN Climate Change and Biodiversity Conferences. But we should remember that the causes of the crises are interlinked – that they have already collided - and that inaction over both may result in dire consequences,” said Willcock. 

“Previous studies of ecological tipping points suggest significant social and economic costs from the second half of the 21st century onwards.  Our findings suggest the potential for these costs to occur much sooner,” added co-author Professor John Dearing.

An example is the UN’s International Panel on Climate Change (IPCC) estimate for a tipping point in the Amazon Forest prior to 2100. The new study suggests a breakdown may occur several decades earlier than predicted by the IPCC. For example, it is well known that the Amazon Forest is threatened by deforestation. However, it is easy to imagine how global warming and extreme climate events such as droughts and wildfires add to this stress. This may decrease the Amazon’s ability to generate its own rainfall, making it drier and more vulnerable – resulting in the ecosystem spiralling down in a doom-loop. 

“All four of the ecological systems we looked at showed the same overall outcomes,” said co-author Dr Gregory Cooper. “This has potentially profound implications for our perception of future ecological risks. While it is not currently possible to predict how climate-induced tipping points and the effects of local human actions on ecosystems will connect, our findings show the potential for each to reinforce the other. Any increasing pressure on ecosystems will be exceedingly detrimental and could have dangerous consequences”

This research was carried out in part under the Resilient Farming Futures Institute Strategic Programme at Rothamsted Research, funded by the BBSRC

About Rothamsted Research
Rothamsted Research is the longest-running agricultural research institute in the world. We work from gene to field with a proud history of ground-breaking discoveries, from crop treatment to crop protection, from statistical interpretation to soils management. Our founders, in 1843, were the pioneers of modern agriculture, and we are known for our imaginative science and our collaborative influence on fresh thinking and farming practices.
Through independent science and innovation, we make significant contributions to improving agri-food systems in the UK and internationally. In terms of the institute’s economic contribution, the cumulative impact of our work in the UK was calculated to exceed £3000 million a year in 20151. Our strength lies in our systems approach, which combines science and strategic research, interdisciplinary teams and partnerships.
Rothamsted is also home to three unique resources. These National Capabilities are open to researchers from all over the world: The Long-Term Experiments, Rothamsted Insect Survey and the North Wyke Farm Platform.
We are strategically funded by the Biotechnology and Biological Sciences Research Council (BBSRC), with additional support from other national and international funding streams, and from industry. We are also supported by the Lawes Agricultural Trust (LAT).
For more information, visit https://www.rothamsted.ac.uk/; Twitter @Rothamsted
1Rothamsted Research and the Value of Excellence: A synthesis of the available evidence, by Séan Rickard (Oct 2015)

About BBSRC
The Biotechnology and Biological Sciences Research Council is part of UK Research and Innovation, a non-departmental public body funded by a grant-in-aid from the UK government.
BBSRC invests in world-class bioscience research and training on behalf of the UK public. Our aim is to further scientific knowledge, to promote economic growth, wealth and job creation and to improve quality of life in the UK and beyond.
Funded by government, BBSRC invested £469 million in world-class bioscience in 2016-17. We support research and training in universities and strategically funded institutes. BBSRC research and the people we fund are helping society to meet major challenges, including food security, green energy and healthier, longer lives. Our investments underpin important UK economic sectors, such as farming, food, industrial biotechnology and pharmaceuticals.
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About LAT
The Lawes Agricultural Trust, established in 1889 by Sir John Bennet Lawes, supports Rothamsted Research’s national and international agricultural science through the provision of land, facilities and funding. LAT, a charitable trust, owns the estates at Harpenden and Broom's Barn, including many of the buildings used by Rothamsted Research. LAT provides an annual research grant to the Director, accommodation for nearly 200 people, and support for fellowships for young scientists from developing countries. LAT also makes capital grants to help modernise facilities at Rothamsted, or invests in new buildings.