Human population growth over the next 40 or so years will cause the extinction of a great number of mammal and bird species, according to new research from Ohio State University.
Image Credit: Tarsier via Flickr CC
The new research states that a typical growing nation should expect at least 3.3% more threatened species in the next decade and an increase of 10.8% species threatened with extinction by 2050. (Author’s note: When taken together with the large body of previous research on this subject, these figures are very ‘optimistic’…)
As per the research — the US is currently ranked sixth in the world with regards to the number of new species expected to be listed as ‘threatened’ by 2050.
While there has been previous work done which has suggested “a strong relationship between human population density and the number of threatened mammal and bird species at a given point in time,” this is the first that definitively links expanding human populations to a decline for these other species, and to their possible extinction.
The lead researcher of this new work had previously created “a model based on 2000 data to forecast future threatened species connected to human population growth projections, and published the predictions in 2004. In this new study, that model’s predictions were confirmed by 2010 actual figures.” The researchers then utilized the same model — which contains data on 114 countries — to extend the predictions to the year 2050.
“The data speak loud and clear that not only human population density, but the growth of the human population, is still having an effect on extinction threats to other species,” said Jeffrey McKee, professor of anthropology at Ohio State and lead author of the study.
“The findings suggest that any truly meaningful biodiversity conservation efforts must take the expanding human population footprint into consideration — a subject that many consider taboo.”
“Our projection is based on human population density alone. It doesn’t take into account climate change, industrialization or wars. So the actual numbers that we predict for 2050 will be very different because everything we do will exacerbate the problem,” he said. “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.”
Ohio State University explains the specifics of the research:
McKee collected data on threatened species from the International Union for Conservation of Nature Red List, and obtained human census data for 2000 and 2010 from the world database of the U.S. Census Bureau. Overall species richness data came from the United Nations Environment Programme-World Conservation Monitoring Centre’s Animals of the World Database. He created a model using equations to analyze relationships among these variables.
After using 2010 data to confirm that the decade-old predictions came true, the researchers used the same equations to determine that between now and 2050, the nations that see the most population density growth will experience higher numbers of species facing new threats of extinction.
Only five nations rank higher than the United States in predicted new species threats by 2050. The Democratic Republic of the Congo tops the list, with a predicted new threat to more than 20 species in that time frame. The analysis suggests about 11 species will be newly threatened with extinction in the United States.
The model also suggests that the 21 countries with projected declining human populations by 2050 will see an average reduction in threatened species of 2.5%. The findings were bolstered by the fact that nine of the 12 nations with population declines between 2000 and 2010 showed a modest decrease in the number of threatened species of mammals and birds.
“There are an estimated 12 million species of plants and animals on earth, and the human population exceeds 7 billion — with a gain of an estimated 214,000 people each day.”
“When the population stood at 6 billion, McKee led a project with his students in which the group divided the planet’s land surface area among all the world’s people to determine how much space was available to each person. At that time, each of the world’s humans could claim space roughly equivalent to Ohio Stadium, which seats more than 102,000 football fans.”
“If we get to 11 billion people, which is where we’re supposed to peak, then the amount of space you have per person is a lot smaller than that stadium. When you’re left with less space, there’s virtually no space left for most other species,” he said.
The new research was published this week in the journal Human Ecology.
