Tuesday, February 18th 2020, 6:20 pm - Hundreds of species, particularly those in the tropics, face local extinctions if atmospheric temperatures continue to rise.
Climate change is an imminent threat to global biodiversity and the risk to plant and animal species is continuously rising as scientists learn more about how warming temperatures will impact habitats.
If we do not start taking action to mitigate the effects of human-caused climate change, the impact on global biodiversity could be devastating during the next 50 years, according to a new study conducted by scientists from the University of Arizona. The results found that one out of three plant and animal species will face extinction by 2070 under current global emission trends. According to John Wiens, one of the researchers involved in the study, the alarming figures could be considerably reduced if we follow the Paris Agreement signed back in 2015 to reduce greenhouse gas emissions.
The study uses information from specific changes in 19 climatic variables that have been associated with past widespread local extinctions. Data from 538 plant and animal species from hundreds of locations around the world provide valuable information that relates to climate change and species extinction. In the past, these places that experienced local extinctions had larger and faster changes when hotter temperatures were measured than those without the heat.
About half of the species experienced local extinctions when average high temperatures increased by 0.5°C. The number of local extinctions jumped to an alarming 95 per cent when the average high temperature rose by 2.9°C. If we continue on a business-as-usual trend for greenhouse gas emissions, the Intergovernmental Panel on Climate Change (IPCC) projects that Earth could be 2.6 to 4.8°C warmer than pre-industrial levels by 2100.
The research team concluded that local extinctions occurred in places with smaller changes in the average annual temperature, which indicates that large changes in annual temperatures are not indicative of past extinctions. They also evaluated if species can survive climate change by dispersing and shifting their niches to tolerate warmer conditions. With dispersal alone, 57 to 70 per cent of species would still face extinction. However, if niche shifts are considered together with dispersal, those potential 2070 extinction figures can drop by 30 per cent or less.
In the past, studies of species extinction related to climate change had shown species migration to cooler environments as an attempt to avoid warming conditions. This particular study now shows that even if species disperse to other areas, many will not be able to do it fast enough to avoid extinction. According to team researcher Cristian Roman-Palacios, the extinction of animals and plants would be two to four times more frequent in tropical than in temperate regions, which is troubling because most species today are located in tropical regions.