The extinction of species caused by extreme environmental damage could create a catastrophic chain of events (or “extinction domino effect”) that will wipe out every single animal on the planet. And yes, that includes humans.
This is according to a study published in the journal Scientific Reports – happy Friday, everyone.
It comes down to a concept called co-extinction. This is the idea that a species will suffer (and eventually face extinction) if an organism it relies on dies out. Think of a flower that depends on a particular pollinator. Or a parasite that's entirely reliant on its host. Eventually, the death of these species could cause the entire eco-system to come tumbling down, affecting even the hardiest of creatures.
“Even the most resilient species will inevitably fall victim to the synergies among extinction drivers as extreme stresses drive biological communities to collapse,” the study authors warn.
"Furthermore, co-extinctions are often triggered well before the complete loss of an entire species."
Giovanni Strona of the European Commission's Joint Research Centre and Corey Bradshaw of Flinders University came to this conclusion after simulating 2,000 “virtual Earths” and subjecting each to environmental changes sparked by various disaster scenarios, from the impact of a large asteroid or series of automatic bombs (triggering a “nuclear winter”) to runaway global warming.
The purpose of the exercise was to test how the tolerances of different species to different levels of global warming or cooling affected extinction rates. Instead, they ended up showing the passing of less tolerant species brought more tolerant creatures down with them in a domino effect – because, ultimately, “all species are connected in the web of life”. The researchers note that while the models are a simplifaction of ecological reality, the results proved consistent with real-world phenomena like the Permian extinction, which almost annihilated life on the planet.
"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," Bradshaw explained.
This result would hold true whatever triggered this temperature-provoked species decline but now that tensions between North Korea and the US appear to have cooled off, the most serious threat is climate change caused (at least in part) by humanity’s gas-guzzling lifestyle. According to Strona, “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.”
Which is not a particularly cheery way to end the week – particularly one where we have heard that the Amazon is being destroyed at the fastest rate in a decade, CO2 emissions are rising for the first time in four years, and 2018’s exceptionally high temps are expected to make the last four years the hottest on record. Not to mention the Trump administration's (failed) attempt to bury its own climate report.
But we are not doomed yet. Green energy is (slowly) taking over, despite efforts by certain figures to hold it back. More and more places are pledging to switch to renewables (or at least go climate neutral). And, encouragingly, more people than ever before are prepared to acknowledge that climate change is happening – and that we are at least partly to blame.
According to the latest reports, it will be a struggle but it is still possible to limit warming to the 1.5°C advised by the IPCC, provided we act quickly. This would avoid the worst effects of climate change and keeps us well below the 5 to 6°C that could spark an “extinction domino effect”.