Together, climate and land use change pose massive threat

For decades now, scientists have been trying to understand the implications of climate change for species around the world. But climate change isn’t the only major environmental transformation being driven by humans. Land use changes are also impacting ecosystems that wildlife relies on across the planet. What happens when these two forces combine?

New research suggests that together, climate change and land use change could wipe out a large portion of terrestrial vertebrate species in ecological communities over the next several decades.

“When I looked at the combined effects of climate and land use, predictions of change were very high losses of biodiversity,” said Tim Newbold, the author on the study published in Proceedings of the Royal Society B.

A research fellow with the United Kingdom’s University College London, Newbold used maps that conservatively estimated present and future land uses, such as cultivation, livestock grazing and human habitation. He complemented those maps with climate forecasts and analyzed tens of thousands of birds, mammals, reptiles and amphibians under four carbon emission scenarios of varying severity projected out to 2070.

Land use change has already brought about the loss of 11 percent of vertebrate species from the average community, Newbold found, but over time, climate change will have a far greater impact. By 2070, it could cause the local extinction of nearly 29 percent of vertebrates from communities on average if current greenhouse gas conditions continue, he determined. Considering climate change and land use change together, nearly 40 percent of vertebrate species could be lost, with reptiles and amphibians being hit the hardest.

“By considering climate and land use together, we can balance strategies like biofuel plantations, which are good in terms of avoiding climate change but bad because they cause a lot of habitat to be destroyed,” Newbold said.

He recommends prioritizing climate mitigation over habitat conservation when necessary to most effectively protect biodiversity, but he also emphasizes combating climate change without habitat-degrading biofuels. “Because climate change is predicted to become the biggest effect, the best strategies are avoiding climate change,” Newbold said. “Even once you take into account the negative land use impacts of biofuel plantations, that scenario that mitigates climate change aggressively through biofuels emerges the best overall for biodiversity, but if we can do it in ways that are less damaging than biofuels to biodiversity, that’s going to be better.”

Header Image: Reptiles like the Coachella Valley fringe-toed lizard could be especially at risk of local extinction under the combined forces of land use and climate change. ©Tom Benson