Photo: Ed Schipul/Flickr
Hot on the heels of the latest United Nations forecast for population growth over the rest of this century (the middle of the road estimate is now 9.6 billion of us by 2050) comes a new report in Human Ecology examining the impact of more humans on species threatened with extinction. In the words of the report authors, the "outlook is grim."
Study lead author Jeffrey McKee of Ohio State University didn't mince words, saying, "You can do all the conservation in the world that you want, but it's going to be for naught if we don't keep the human population in check."
McKee and company found that that in countries with average levels of population growth, at least 3.3 percent more species will be threatened with extinction in the next ten years. By 2050, that population growth—again, at average levels—will produce an increase in threatened species of 10.8 percent.
On a global level the human population growth rate is just about 1.1 percent annually. That's about half what it was when the growth rate peaked in the early 1960s. Nevertheless, it still means that it took just 40 years for the human population to double from 3 billion (in 1960) to 6 billion (in 1999), a rate more than twice as quick as the previous doubling in population.
Over half of all population growth between now and 2050 is projected to occur in Africa, with Nigeria leading the pack. That has huge ramifications for African wildlife, which has already been impacted heavily in recent decades. Two thirds of Africa's forest elephants, for example, were poached in the last decade.
The connection between human population and threatened species works in the reverse as well, the study shows. In the 21 nations where population is expected to decline through 2050, the average number of threatened species is expected to decline by 2.5 percent.
Saying a species is threatened with extinction covers several levels of concern. Under the categorization by the International Union for Conservation of Nature, species categorized as threatened with extinction proceed from being classified as vulnerable to endangered to critically endangered—before meeting their eternal doom as extinct in the wild or just plain old extinct.
In ranking nations with the most-dramatic nexus of population growth and endangered species, the study finds that the Democratic Republic of Congo will likely have have the greatest number of newly-endangered species, with 20 more stepping on the road to extinction in the next few decades just because there are more humans around. The United States is sixth, with an estimated 11 additional threatened species by 2050.
The population growth alone part cannot be overstated. As the report authors emphasize, their work doesn't take into account the additional number of species that could become threatened with extinction due to climate change, wars, or any other factor that simply there being more humans around.
A recent IUCN report found that 24-50 percent of bird species are highly vulnerable because of climate change, with 24-44 percent of amphibians, and 15-32 percent of coral vulnerable. A more comprehensive study, published in Nature, concluded that 15-37 percent all species on the planet will be "committed to extinction" by 2050 due to the effects of climate change.