After running thousands of computer simulations, experts have revealed that a worst-case scenario would be “co-extinctions”. This is where a smaller species dies off, leading to the extinction of an animal or plant higher up the food chain. Eventually, this domino effect could lead to the death of all organisms on the planet, scientists have warned in a doomsday scenario.
Lead author of the research published in Scientific Reports, Dr Giovanni Strona of the European Commission’s Joint Research Centre based in Ispra in northern Italy, said: “Even the most resilient species will inevitably fall victim to the synergies among extinction drivers as extreme stresses drive ecosystems to collapse.”
The team came to this conclusion after running 2,000 simulated “virtual Earth’s” where they linked one animal or plant extinction to another.
Some of the extreme changes to the environment that the scientists simulated was runaway global warming, scenarios of ‘nuclear winter’ following the detonation of multiple atomic bombs, and a large asteroid impact.
Co-author Professor Corey Bradshaw of Flinders University in South Australia said: “What we were trying to test is whether the variable tolerances to extreme global heating or cooling by different species are enough to explain overall extinction rates.”
“But because all species are connected in the web of life, our paper demonstrates that even the most tolerant species ultimately succumb to extinction when the less-tolerant species on which they depend disappear.”
“Failing to take into account these co-extinctions therefore underestimates the rate and magnitude of the loss of entire species from events like climate change by up to 10 times.
“Not taking into account this domino effect gives an unrealistic and exceedingly optimistic perspective about the impact of future climate change.”
Dr Strona added that it would not take much in the way of climate change to induce a huge global die off.
He said: “Another really important discovery was that in the case of global warming in particular, the combination of intolerance to heat combined with co-extinctions mean that 5-6 degrees of average warming globally is enough to wipe out most life on the planet.”
Prof Bradshaw says the next step of the research will focus on how climate warming creates extinction cascades in the worst possible way.