Penguin exposure to climate change inferred through CMIP6 projections

LOIS, NICOLÁS A.; RISARO, DANIELA B.; RAYA REY, ANDREA

Virtual

Congreso; Climate change and birds: solutions to the crisis; 2020

British Ornithological Union

Oceans have been affected by global change and are expected to suffer higher impacts in the near future according to the most recent climate models. In order to develop effective species-targeted conservation measures we need to first assess their vulnerability to climate change. In this work we evaluate the exposure of penguins to global climate change under 2 different CMIP6 scenarios for the next century. We ensembled between 9 and 14 climate models for Sea-Surface Temperature (SST) for three CMIP6 experiments: 'historical' and two ScenarioMIP (SSP2-45 and SSP5-85). The 'historical' ensemble models recent past while SSPs are projections forced by low and high CO2 emissions respectively. We analyzed the difference between 2075-2100 (ScenarioMIP) monthly climatology to 1975-2000 ('historical') for each penguin distribution during breeding, non-breeding and pre-molt stages (IUCN & Birdlife). Climate change confers a heterogeneous impact on SST in the southern hemisphere and therefore on penguin species. No significant differences were encountered between reproductive stages, so data was pooled. The lowest net change in SST is present south of the Antarctic Circumpolar Current (ACC). Thus, Antarctic-dwelling penguins are the least exposed to SST increase. In the Southern Ocean, north of the ACC, penguins with global distributions present intermediate exposure, while penguins inhabiting New Zealand and Australia are among the most exposed. Remarkably, the little blue penguin presents a stable population and low IUCN vulnerability classification, but is the third most exposed species to SST increase. Hopelessly, the most endangered species with lowest populations today are among the most impacted with changes in SST of up to 4 °C for the Humboldt and Galapagos penguin, and 2.8 °C for the African penguin. Other impacts such us sea ice cover and chlorophyll concentration variation should be evaluated and complemented with demographic modelling for better predicting these species faith in the face of global change.