Mass extinction imminent?

TUESDAY, 15 MARCH 2011

The concern follows a study conducted by a team of palaeobiologists from the University of California. They compared current extinction rates with those estimated from the fossil record, and assessed the likelihood of extinction for a variety of species. Their study suggests that losing species that are currently considered ‘critically endangered’ would propel the world into a state of mass extinction. Additional losses of ‘endangered’ and vulnerable’ species could accomplish the sixth mass extinction in just a few centuries Nature, 471(7336), 51-57. doi:' target='_blank' rel='noopener noreferrer'>^[1] .

The stage appears to be set for another extinction event. Global changes in atmospheric carbon dioxide levels and above-typical increases in temperature are both in line with conditions that characterised previous mass extinctions, each of which saw three-quarters or more of all animal species go extinct. Combined with this are habitat fragmentation, pollution, overfishing, threats from invasive species and an expanding human biomass.

The principal author of the study, Anthony D. Barnosky, provided some reassurance on this alarming research."So far, only 1 to 2 percent of all species have gone extinct in the groups we can look at clearly, so by those numbers, it looks like we are not far down the road to extinction. We still have a lot of Earth's biota to save ^[2]."

However, just because the magnitude is low compared to the biggest mass extinctions we've seen in the last half a billion years doesn't mean to say that the species losses aren't significant. The huge difference between where we are today, and where we could easily be in a few generations, reveals the urgency of relieving the pressures that are pushing species towards extinction.

Written by Elizabeth Anne Bateman

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