A recent report from the World Wildlife Fund has found that two-thirds of vertebrate animals could be extinct by 2020.
Habitat loss, climate change and pollution are just a few reasons cited by the report as major contributors. Unlike previous mass extinctions where asteroids and meteors were to blame, the WWF says humans are responsible for the current state of the environment.
But some researchers are skeptical about these numbers.
Larry Mantle sat down with Robin Freeman, research fellow and Head of Indicators and Assessments Unit at the Zoological Society of London and Stuart Pimm, professor of conservation ecology at Duke University, to break down the report and assess its implications.
Click on the blue playhead above to hear the full discussion, or read highlights below.
On the legitimacy of the statistic
Pimm: I think this survey is horribly misleading... It's basically designed to promote WWF's fundraising activities. And so they're interested in a large, single, alarming statistic. And the problem is much more complicated than that. There are places where species are doing quite well thanks to very energetic conservation efforts, there are places where we just don’t know [...] To come up with a single number leads people to think we have much better data than we do.
Freeman: This statistic is about how much populations of wild species have declined... It's not that these populations are going extinct - they're still here, they're just smaller [...] While the headline number of 58 percent has a lot of variability around it, I think the really important details come when you begin to break that number down.... How can we use this large data set to look at how things like habitat loss are impacting these species?... I still think this number can be a useful tool.
So what does this mean about the takeaways of the report?
Pimm: There's no question that Robin [Freeman]'s overall conclusion is right. That species are declining ...The problem is severe but if you come up with a number like this, it suggests we'll have no wildlife left in 25 years time and then people are going to come back and say, ‘look you're being alarmist.’
Is there a downside to this kind of statistic?
Pimm: We don’t want people to simply be discouraged and think there's nothing we can do [...] Once a species gets put on that endangered species list, it has a really good chance of surviving. Moreover, there are spectacular success stories. There's gray whales, off the California coast... The gray whale, like many other whales, was driven to the very edge of extinction - it's now coming back... That's a remarkable success story of what we can do in the ocean if we want to put our minds to it.
What can we do moving forward?
Pimm: There are so many things we can do, so many individual choices — do I eat fish? Yes, I go to the Monterey Bay Aquarium website and find out what fish I can eat.... Let's be encouraged when we should be, let's be worried when we should be and let's get better data when we don't know.
This interview has been edited for clarity.
Robin Freeman, research fellow and Head of Indicators and Assessments Unit at the Zoological Society of London