Synergistic impacts of global warming and thermohaline circulation collapse on amphibians

Julián A Velasco,Carlos Gay,Didier Swingedouw,Francisco Estrada,Oscar Calderón-Bustamante,Dimitri Defrance,Carolina Ureta

doi:10.1038/s42003-021-01665-6

Abstract

Impacts on ecosystems and biodiversity are a prominent area of research in climate change. However, little is known about the effects of abrupt climate change and climate catastrophes on them. The probability of occurrence of such events is largely unknown but the associated risks could be large enough to influence global climate policy. Amphibians are indicators of ecosystems’ health and particularly sensitive to novel climate conditions. Using state-of-the-art climate model simulations, we present a global assessment of the effects of unabated global warming and a collapse of the Atlantic meridional overturning circulation (AMOC) on the distribution of 2509 amphibian species across six biogeographical realms and extinction risk categories. Global warming impacts are severe and strongly enhanced by additional and substantial AMOC weakening, showing tipping point behavior for many amphibian species. Further declines in climatically suitable areas are projected across multiple clades, and biogeographical regions. Species loss in regional assemblages is extensive across regions, with Neotropical, Nearctic and Palearctic regions being most affected. Results underline the need to expand existing knowledge about the consequences of climate catastrophes on human and natural systems to properly assess the risks of unabated warming and the benefits of active mitigation strategies.

Highlights

Impacts on ecosystems and biodiversity are a prominent area of research in climate change
The control run is based on the RCP8.5 emissions scenario for the period 2006–2100 and four hosing experiments were superimposed to the RCP8.5 which added 0.11, 0.22, 0.34, and 0.68 Sv (1 Sv = 106 m3/s; labeled as A, B, C, and D, respectively) of freshwater released in the North Atlantic from 2020 to 207029
These hosing experiments lead to different levels of additional weakening of Atlantic meridional overturning circulation (AMOC) over the century (Fig. S2)

Summary

Introduction

Impacts on ecosystems and biodiversity are a prominent area of research in climate change. We present a global assessment based on an ecological niche modeling approach (see “Methods”, Supplementary Information S3) of the synergistic effects of unabated global warming and different levels of AMOC slowdown for 2509 amphibian species across six biogeographical realms (Fig. S1).

Results

Conclusion