Climate change is increasingly perceived as a cause of biodiversity loss. Whilst this is certainly true in many respects, the full picture is complex. These are two of the four forces of the global ecosystem that have exceeded their thresholds known as planetary boundaries. The science of these interactions remains uncertain.

The role of biodiversity as a defence mechanism against climate change is increasingly appreciated. The value of mangrove and coral reef ecosystems in mollifying the impact of rising sea levels and storm surges is an example. In addition to its store of biodiversity, the tropical forest is acknowledged for its stabilising influence over the water cycle, given the threat of erratic rainfall patterns.

Increasingly frantic endeavours to adapt to climate change have highlighted the contribution of biodiversity to food security. Almost every country in the world is scouring its indigenous gene pool for varieties of staple crops that might be tolerant to higher temperatures, drought, floods or salinity.

Alas, this prospective role as a guardian angel of climate adaptation may prove to be wishful thinking, as biodiversity itself is threatened by climate change. Warming oceans have already caused serious damage to coral reefs through bleaching. Tropical forests too are sensitive to higher temperatures and drought. Ocean acidification, brought about by interaction with greater atmospheric concentrations of carbon dioxide, threatens to disrupt the marine food chain.

A 2017 study published in Science journal warns that “climate change is impelling a universal redistribution of life on Earth.” The lead author states that “land-based species are moving polewards by an average of 17km per decade, and marine species by 72km per decade.” Birdlife is also known to be sensitive to changing temperature of habitats.

Rising temperatures therefore create the perverse situation in which animals and plants need to move out of national parks and other protected areas for their own survival. In the broader context, adaptation of both plants and animals will be obstructed by the physical obstacles of modern times – cities, roads and people. Whilst scientists now believe that they can assist climate migration in the natural world through habitat management, such measures may be scratching the surface.

A 2011 paper published in the Proceedings of the US National Academy of Sciences estimates that climate change alone could be responsible for the extinction of 10%-14% of all species by 2100. The presumption within international climate change agreements that two degrees of global warming represents a tolerable threshold is therefore not strongly supported by the science of biodiversity.

Indeed, studies show that restricting global warming to 1.5 degrees would significantly reduce the threat to biodiversity. Yet the 2015 Paris climate agreement makes almost no reference to the interaction between climate and biodiversity loss.

A damaging feedback loop is therefore at play in which the poorer countries are powerless to prevent a spiralling loss of their biodiversity. The richer countries are the primary agents of both the extraction of resources (a direct cause of biodiversity loss) and their consumption (a direct cause of climate change).

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more Biodiversity briefings (updated May 2018)
The Anthropocene
Importance of Biodiversity
Biodiversity Loss and Planetary Boundaries
Causes of Biodiversity Loss
Conservation of Biodiversity
Solutions to Biodiversity Loss
Sustainable Development Goals for Biodiversity
Biodiversity Finance and Economics
Biodiversity Access and Benefit-Sharing
Source Material and Useful Links