Entering Earth's 6th Great Mass Extinction

6/25/2015 biodiversity , crisis , ecosystem services , extinction 0 Comments

For a decade now it has been widely debated whether humanity has set in motion a sixth great mass extinction event, comparable to the catastrophe which erased the dinosaurs some 66 million years ago. According to a recent study by Ehrlich et al. (2015) there is no longer any doubt, we truly have.

There is general agreement among biologists that extinction rates have reached levels unparallelled since previous mass extinctions on Earth. However, some have believed the numbers to be overestimated. But this new study confirms that species are disappearing up to about 100 times faster than the normal rate between mass extinctions, known as the background rate. If allowed to continue, life would need millions of years to recover.

The study took a precautionary approach and only allowed for conservative estimates, which means that their calculation probably underestimate the severity of the extinction crisis.

As human population continues to grow and consumers become more affluent more and more natural habitats will be altered or destroyed. Already in 2005 scientists warned that about 60% of all ecosystem services had been degraded or destroyed (Millennium Ecosystem Assessmentt). The long list of impacts include: land clearing for farming, logging and settlement, invasive species, carbon emissions that drive climate change and ocean acidification and toxins that alter and poison ecosystems. 

While there is still much discussion about the causes of some mass extinctions, it is generally believed that they can occur when the biosphere is under long-term stress, for example from a warming climate generated by greenhouse gasses in the atmosphere. As ever more species face extinction we lose the vital ecosystem services they provide, such as: pollination, water purification, pest control, storm control, soil regeneration etc. For its continued existence mankind is reliant upon an untold number of species that maintains the function of those services. As these species disappear, that existence becomes increasingly fragile.

Stanford biologist Paul Ehrlich calls for fast action to conserve threatened species and habitat before the window of opportunity closes. Below is a video from Standford with Ehrlich describing the issue.