In a new study, published today in Environmental Research Letters, we assess how much of today’s climate refugia (areas sheltering biodiversity from climate change) may be lost in the future, depending on various levels of global warming and climate action. 
We show that more than 60% of today’s global climate #refugia area may lose its sheltering function towards the end of this century under a warming scenario in line with current climate policies. In other words, warming levels in line with current policies would drastically reduce the climatically suitable range for animal and plant species. 
Compared to current policies, more ambitious climate action, compatible with limiting long-term warming to #1p5C, may more than halve the loss of climate refugia. But even at 1.5 °C, substantial parts of today’s climate refugia would be lost. 
To realize ambitious climate action, most existing decarbonisation scenarios imply land-intensive mitigation efforts in the form of forestation and the cultivation of energy crops. Such land-intensive efforts (if not cautiously implemented) may come with negative climate refugia implications on their own. 
As part of our analysis, we compared climate refugia implications of warming and land-intensive mitigation side-by-side. We show that warming-related global climate refugia loss is substantially larger and arises markedly faster than potential loss due to land-intensive mitigation. Still, high reliance on land-intensive mitigation increases the land allocation in climate refugia. 
In our study, we focused on potential climate refugia implications in scenarios where warming peaks above 1.5 °C, after which warming is reversed again to some degree (#peak-and-decline warming trajectory). We illustrate how climate refugia implications after peak warming strongly depend on species’ ability to recover when warming starts to decline. If species are able to recover and repopulate areas that become climatically suitable again, returning to 1.5 °C by achieving net negative emissions could benefit biodiversity substantially. 
However, for the assessed timescales, only very limited recovery can be expected. Generally, the recovery capacity under peak-and-decline warming is highly uncertain and depends on an array of open questions, including:
- How would ongoing regional climate change under peak-and-decline affect the future location of climate refugia?
- How would peak-and-decline shift ecosystem composition and alter predator-prey or plant-pollinator relationships?
- How would land-intensive mitigation affect species’ migration corridors when tracking shifting climate niches?
More research is required to better understand potential ecosystem responses under peak-and-decline warming. Despite many uncertainties, one thing is clear: constraining overshoot of 1.5 °C by cutting emissions as much as possible is our best chance to limit climate-related biodiversity loss. 
Find the open access study here.
Sabine Fuss, Jeff Price, Rachel Warren, Nicole Forstenhäusler, Yazhen Wu, Andrey Lessa Derci Augustynczik, Michael Wögerer, Tamás Krisztin, Petr Havlik, Florian Kraxner, Stefan Frank, Tomoko Hasegawa, Jonathan Doelman, Vassilis Daioglou, Florian Humpenöder, Alexander Popp and Joeri Rogelj
overshoot biodiversity climate cdr
Humboldt-Universität zu Berlin (Humboldt University of Berlin)
PIK - Potsdam Institute for Climate Impact Research
Grantham Institute - Climate Change and the Environment
International Institute for Applied Systems Analysis (IIASA)
Imperial College London
Tyndall Centre for Climate Change Research
University of Natural Resources and Life Sciences, Vienna (BOKU)
Ritsumeikan University
PBL Planbureau voor de Leefomgeving
Copernicus Institute of Sustainable Development, Utrecht University