City populations are expected to grow by five billion people and expand by 1.2 million square kilometers by 2030. Much of this expansion is forecast to occur in the tropics, which contain the bulk of the world's species. The new study attempts to quantify the impact of urbanization on the world's so-called "hotspots" — nearly three dozen areas with exceptionally high levels of species found no where else.
Using data from a variety of sources, researchers at Yale University, Texas A&M University, and Boston University developed a probabilistic model for estimating the impacts of urbanization on vegetation, carbon stocks, and threatened species. They found that by 2030, nearly three percent of hotspot areas will be urbanized, up from one percent in 2000. While the extent seems small, paving over marshes, forests, and grasslands could generate 1.38 billion tons of carbon emissions (5 billion tons of CO2) from direct land use change. Some 214 species currently listed as endangered and critically endangered and considered focal species by the Alliance for Zero Extinction (AZE) would be affected by urban expansion, including 20 — 15 of which are amphibians — that would experience complete urbanization of their habitat.
The biggest biodiversity impacts would occur in Africa and Europe, whereas the biggest increase in hotspot urbanization is forecast in Africa and Asia, specifically the Eastern Afromontane, the Guinean Forests of West Africa, the Western Ghats and Sri Lanka hotspots, according to the study.
Via Dr. Stefan Gruenwald