One in six species on the planet will be at risk for extinction because of climate change if humans don’t curb their carbon emissions soon, according to a study published in Science today. Buildings, powerlines, antennas, and wind farms are also causing millions of animal deaths each year, according to a second study published in Science today. Overall, humanity’s effect on animal species isn’t looking very good.
"We face losing one in six species."
"Global biodiversity provides the foundation for economy, culture, food, and human health," says Mark Urban, an ecologist at the University of Connecticut and the author of the extinction study. Unfortunately, "if we continue on our current trajectory of greenhouse gas emissions, we face losing one in six species."
In the extinction study, Urban compiled results from a number of published studies in order to produce an analysis of climate-induced extinctions risks. As global temperatures continue to rise, the loss of species diversity is accelerating, he found. Urban's study also revealed that species face the highest extinction risk in South America, Australia, and New Zealand. And in one model of climate change, Urban assumed a modest rise in temperature — only two degrees, compared with temperatures recorded before the Industrial Revolution. Even using that figure, which is widely considered an underestimation, the extinction risk for any species of animal almost doubles, to 5.2 percent from 2.8 percent. Should temperatures increase by 4.3 degrees Celsius, however, 16 percent of the world’s species could find themselves at risk for extinction.
To forecast extinction risks, Urban looked at factors including species characteristics and distributions, global temperatures, and a region's features. "I spent lots of my time searching for studies that predicted extinction risk from climate change, understanding them, and extracting data," Urban says. "It took me over a year to find 131 studies out of thousands." Urban also made sure to weed out lower-quality studies. "For example, I concentrated on multi-species studies that are less likely to choose a particular species because of its predetermined risk," he says.
In the second study, scientists looked at the effect of human activity on airspace. As with the extinction study, the researchers compiled results from previous published work. They found that buildings, wind farms, powerlines, and antennas threaten billions of animals each year and cause millions of deaths. Animals crash into windows and planes, for instance, and are forced to alter migration patterns. And this isn’t just causing animal deaths; over 200 people have been killed because of aircraft collisions with birds, the researchers note.
"We are drawing attention to the importance of the airspace."
"It was only as recently as 2013 that researchers proposed that the airspace be recognized as habitat," says Emily Shepard, a bioscientist at Swansea University in the UK and a co-author of the airspace study. "We are drawing attention to the importance of the airspace, in terms of all the organisms that depend on it and the services they provide."
Overall, collision rates are increasing, she says. And new uses of the airspace, such as drones, are also likely to cause conflict — "though this is so new that there has only been one systematic study of the effects of drones on animals to date, and this focused on three species of waterbird."
There have been some successful interventions that have helped reduce conflict. New York City, for example, announced that it would join others cities in the US that will turn off their lights when songbirds migrate; lights can disorient birds and cause them to crash into windows. Still, there's a lot more that could be done to reduce human-animal competition for airspace. Efforts like making windows more visible and maintaining untouched "airspace reserves" for aerial wildlife, for instance, would go a long way.
Now that the extinction study has been published, Urban is working on developing more sophisticated models of predicting responses to climate change that incorporate things like species interactions, for instance. And the airspace researchers are hoping to collaborate on a map of the movements of Andean Condors. "Condors are very particular — their huge size means that they are dependent on finding rising air in order to fly and find food," Shepard says. "This dependence means that they will not pick their flight paths at random, they will most likely be using a network of low-cost flyways." Investigating how movements of the air influence the birds' chosen path will ultimately help them understand how to avoid potential conflict with humans.
"We have a chance to determine the fate of biodiversity."
"As a world, we have a chance to determine the fate of biodiversity in December at the UN Conference of the Parties to the UN Framework Convention on Climate Change," Urban says. "We can choose to adopt stringent policies that limit this risk." Scientists also need to develop better, more accurate models for predicting extinction risks that incorporate our complete collective understanding of responses to climate change, he says. Doing that will ensure that we can determine which species are most at risk of extinction — "and implement conservation strategies to protect them."