Ecosystems are beyond 'tipping point' now
Source: Middle East Insurance Review | Aug 2023
Extreme weather events such as wildfires and droughts will accelerate change in stressed ecosystems leading to quicker tipping points of ecological decline, according to a new study published by Rothamsted Research.
The research, published in a recent issue of scientific journal Nature Sustainability, revealed that 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 imperil natural systems.
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. The team led by Rothamsted Research professor Simon Willcock, 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.
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%.
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 by 1.5°C will increase those numbers further. Scientists are also concerned about possible knock-on effects as one collapsing ecosystem impacts neighbouring ecosystems. M