Experts Warn Climate Change Will Become Primary Driver of Biodiversity Loss
The purpose of the study is not to predict what will happen, but to understand alternatives and avoid these trajectories, the researchers say.
The projection comes from a new study led by the German Centre for Integrative Biodiversity Research (iDiv) and the Martin Luther University Halle-Wittenberg (MLU), and involving a researcher at the University of York.
In the largest multi-model study of its kind, the research also confirms that land-use change (such as cutting down forests to create agricultural land) is the largest driver of biodiversity loss in the present day and may have already caused a global biodiversity decline of between two and eleven percent.
To provide “the most comprehensive estimate of biodiversity trends worldwide” the scientists looked at thirteen different ways of predicting how changes in land-use and climate change might affect four different measures of wildlife diversity, like the variety of species, and nine ways that nature benefits us, like clean water and pollination.
Future scenarios
While land-use change will remain relevant, climate change stands to put additional strain on biodiversity and ecosystem services by 2050, according to the findings.
The researchers assessed three widely-used scenarios for the future – from a sustainable development to a high emissions scenario. For all scenarios, the impacts of land-use change and climate change combined result in biodiversity loss in all world regions.
While the overall downward trend is consistent, the study identified considerable variations across world regions, models, and scenarios.
Avoid trajectories
Co-author of the study and co-lead of the model analyses, Dr Inês Martins from the Leverhulme Centre for Anthropocene Biodiversity at the University of York, said: “The purpose of long-term scenarios is not to predict what will happen. Rather, it is to understand alternatives, and therefore avoid these trajectories, which might be least desirable, and select those that have positive outcomes.
“Trajectories depend on the policies we choose, and these decisions are made day by day.”
The authors also note that even the most sustainable scenario assessed does not deploy all the policies that could be put in place to protect biodiversity in the coming decades. For instance, bioenergy deployment, one key component of the sustainability scenario, can contribute to mitigating climate change, but can simultaneously reduce species habitats. In contrast, measures to increase the effectiveness and coverage of protected areas or large-scale rewilding were not explored in any of the scenarios.
Most effective
Assessing the impacts of concrete policies on biodiversity helps identify those policies most effective for safeguarding and promoting biodiversity and ecosystem services, according to the researchers.
First author of the study, Professor Henrique Pereira, from iDiv and MLU, said: “Our findings clearly show that current policies are insufficient to meet international biodiversity goals. We need renewed efforts to make progress against one of the world’s largest problems, which is human-caused biodiversity change.”