Climate change & extinction: what elephant seals and current climate research teach us about Earth’s future

Climate change is among the greatest threats of our time—with far-reaching consequences for our health, economic stability, and biological diversity. Two current scientific studies show what disturbing effects unchecked global warming could have on ecosystems and life on Earth—and why we urgently need to act.

Elephant seals as witnesses of past climate change & a warning for the future

A study published in the journal Global Change Biology shows how closely the history of southern elephant seals (Mirounga leonina) is linked to climatic changes in Earth’s history and the influence of humans. Once, together with fur seals, prehistoric sea lions, and penguins, they populated the beaches of New Zealand—their range extended across large parts of the Southern Ocean, from South Africa to Western Australia and New Zealand.

Using genetic analyses of subfossils from New Zealand, Tasmania, and Antarctica—some up to 8,000 years old—the researchers reconstructed the species’ former range and genetic diversity. Climate data show that during the ice ages the animals survived in several refugia, including South Africa, Australia, New Zealand, and South America.

With the arrival of humans, however, the species’ decline began: Indigenous communities hunted elephant seals for food and made jewelry from their teeth. In the 19th century, European sealers massively decimated the populations—the animals’ coveted oil was used as lamp fuel.

This intensive exploitation drove the species to the brink of extermination. Southern elephant seals have been protected only since the 1960s. Today, larger populations survive only on remote subantarctic islands such as South Georgia, Macquarie Island, and the Falkland Islands.

The researchers interpret elephant seals as a biological early-warning system: their fate reflects the vulnerability of many species whose habitats are increasingly shrinking due to climate change and human intervention. Without consistent conservation measures, renewed population crashes and an irreversible loss of genetic diversity threaten.

PIK long-term study: a look into the distant future of our climate

A current long-term climate study by the Potsdam Institute for Climate Impact Research (PIK) paints an alarming scenario for the coming centuries: even under moderate emissions, Earth could warm by as much as seven degrees Celsius by the year 3000.

Particularly dangerous are the so-called feedback effects in the climate system—self-reinforcing processes that further drive global warming and are hardly reversible:

• Thawing permafrost releases enormous quantities of climate-damaging gases such as CO₂ and methane.
• Melting ice sheets reduce the reflection of sunlight (albedo effect), causing Earth to heat up further and the ice to melt even faster.
• Warming oceans lose their ability to absorb CO₂ and release stored greenhouse gases back into the atmosphere.

According to the study, these feedbacks could increase long-term global warming by up to 55%. Even after a complete stop to all emissions, warming would continue because of these processes. The researchers therefore emphasize: it is no longer enough merely to limit emissions. Targeted measures for active CO₂ removal are also necessary to keep global heating within manageable bounds.

The consequences for people and nature would be catastrophic:

• Sea-level rise by several meters – millions of people worldwide would lose their livelihoods.
• Expansion of drylands and deserts – with devastating consequences for agriculture and food security.
• Collapse of marine ecosystems – including coral reefs and fish stocks.
• Increase in extreme weather, water scarcity, and global conflicts over vital resources.

Added to this is the ongoing loss of major natural CO₂ sinks such as tropical rainforests, which further worsens the situation. Especially severe is the deforestation of the Amazon rainforest—one of the most important tipping systems on our planet, whose collapse would have global consequences.

The PIK study makes one thing unmistakably clear: the window of time for stopping these developments is closing rapidly. Only determined action and a global turnaround in climate policy can prevent these processes from becoming unstoppable.

Species loss as an underestimated threat

While global warming is receiving increasing attention, species loss is also continuing unchecked—often less noticed, but just as dramatic. According to the IPBES Global Assessment Report on Biodiversity and Ecosystem Services, up to one million species could be threatened with extinction in the coming decades—mainly due to human activities and climate change.

PIK also warns in its report 10 Must-Knows on Biodiversity: the loss of species and the progressive destruction of ecosystems threaten not only individual animal and plant species, but directly our own foundations of life. Intact ecosystems provide clean air and drinking water, regulate the climate, preserve fertile soils, and offer protection against natural disasters. Their collapse would have severe consequences—ecological, economic, and social.

PIK therefore calls for clear and determined measures:

• Protecting and restoring natural habitats worldwide
• An ecological transformation of agriculture in order to connect climate and species protection and reduce land consumption
• Phasing out environmentally harmful subsidies that continue to drive biodiversity loss and environmental destruction

The message is clear: without a fundamental change of course in climate and biodiversity policy, we risk the stability of the natural systems on which our survival directly depends.

Climate protection is species protection—and our life insurance

The history of elephant seals and the findings of current climate research make clear how closely climate change, species loss, and our own future are intertwined. Unchecked warming would not only destroy the last refuges of species such as elephant seals—it would also threaten our food security, water supply, health, and economic stability worldwide.

But we can take countermeasures:

• Climate-friendly consumption: less meat and fewer animal products, more regional and seasonal foods—this protects climate and biodiversity alike.
• Saving energy and using renewable energy: every kilowatt-hour saved reduces CO₂ emissions and relieves pressure on the climate.
• Preserving and creating habitats: whether in the garden, on the balcony, or through supporting local projects—natural spaces strengthen biodiversity directly on our doorstep.
• Becoming politically active: effective climate and species protection policy needs public pressure—at the municipal level as much as nationally and internationally.
• Sharing knowledge and raising awareness: those who understand the connections act more consciously—and motivate others to do the same.

Climate protection has long since ceased to be an abstract task. It determines whether we and future generations will live on a planet worth living on.

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Sources

• Berg, M. L., Rawlence, N. J., O’Connor, S., Major, H. L., Griggs, J. A., McCormack, F., … & de Bruyn, M. (2025). A dynamic history of population extirpation, persistence and divergence in the southern elephant seal (Mirounga leonina). Global Change Biology, 31(4), e17010. https://doi.org/10.1111/gcb.17010
• Kaufhold, C., Willeit, M., Talento, S., Ganopolski, A., & Rockström, J. (2025). Interplay between climate and carbon cycle feedbacks could substantially enhance future warming. Environmental Research Letters, 20(4), 044027. https://doi.org/10.1088/1748-9326/adb6be
• Thonicke, K., Biber-Freudenberger, L., Friess, D. A., Gasparatos, A., Kimengsi, J. N., Lam, D. P. M., … & Wanger, T. C. (2022). 10 Must Knows from Biodiversity Science 2022. Leibniz Research Network Biodiversity / PIK Potsdam. https://doi.org/10.5281/zenodo.6038916