Temperature overshoot will cause irreversible biodiversity loss: Study

CHENNAI: New research has shown that temperature overshoot above 2 degrees Celsius is likely to cause major and often irreversible damage to biodiversity and ecosystems across the world. The most affected regions losing most of its biodiversity will be the tropics, especially the Amazon, the tropical African coast, Indian Ocean, Southeast Asia and the Indo-Pacific.


Researchers from the University of Cape Town (UCT) and University College London (UCL) looked at what this temperature overshoot would mean for about 30,000 marine and terrestrial species if they were temporarily exposed to unsafe temperatures.

Key findings include that during the overshoot period, impacts on biodiversity are likely to arrive abruptly and disappear very slowly. Biodiversity impacts will last longer than the temperature overshoot itself.

Scientists warn that carbon dioxide removal technologies carry their own biodiversity impacts. They warn that even if temperature levels are bought back under control, some species will not recover from the overshoot.

Tropical regions are most affected by these risks, with over 90% of species for many locations in the Indo-Pacific, Central Indian Ocean, Northern Sub-Saharan Africa and Northern Australia pushed outside of their thermal niches. And in the Amazon, one of the most species-rich regions of the world, more than half of the species will be exposed to potentially dangerous climate conditions.

For around 19% of the total number of sites studied, including the Amazon, it is uncertain whether the share of exposed species will ever return to pre-overshoot levels.

And a further 8% of sites are projected to never return to those levels at all. This means that this temperature overshoot can cause irreversible impacts to nature. Species will go extinct and radical transformations of ecosystems will be irreversible even though the global temperatures may be back to normal.

Dr Andreas Meyer of the African Climate and Development Initiative (ACDI) at UCT said, “In the Amazon, this could mean replacement of forests with grasslands, and as a consequence, the loss of an important global carbon sink, which would have knock-on effects on multiple ecological and climatic systems as well as our ability to curtail global warming.”

Dr Joanne Bentley of the ACDI said, “It is important to realise that there is no ‘silver bullet’ solution for mitigating climate change impacts. We have to rapidly reduce greenhouse gas emissions. Many carbon dioxide removal technologies and nature-based solutions, such as afforestation, come with potential negative impacts. Our study shows that should we find ourselves overshooting the 2.0°C global warming target, we could pay dearly in terms of loss of biodiversity, compromising the provision of the ecosystem services that we all rely on for our livelihoods. Avoiding a temperature overshoot should be a priority, followed by limiting the duration and magnitude of any overshoot.”

The research was funded by a collaboration between the UK Royal Society and the African Academy of Sciences.