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A warming world threatens the planet’s library of life
April 16, 2018
Climate change in the coming decades – even if global temperature rise can be kept to below 2°C – will adversely affect animal and plant species across the world. If the world adopts a “business as usual” approach, and we see a rise of 4.5°C, many more species could die off.
This is the basic finding of new research by the World Wildlife Fund, the Tyndall Centre for Climate Change at the University of East Anglia in the United Kingdom, and James Cook University, Australia.
The study, Wildlife in a Warming World, looked at 35 “Priority Places” for conservation throughout the world. It found that:
Today’s climatic extremes are tomorrow’s new normal. Extreme hot and dry years in the past have often led to significant declines in species’ populations.
We will need stronger climate mitigation efforts if we are to avoid severe loss of biodiversity. While the Paris Agreement aims to limit the average global temperature rise to well below 2°C (aiming for 1.5°C), current national climate pledges set us on a course to around 3.2°C of warming. As the temperature rises, so does the proportion of species at risk. With 4.5°C of warming, almost 50 per cent of the species currently found in Priority Places are at risk of local extinction. But if temperature rises are limited to 2°C, this risk is halved, underlining the importance of urgent action to cut greenhouse gas emissions.
Even a 2°C rise will lead to widespread biodiversity losses. Under a 2°C scenario, almost 25 per cent of species in Priority Places are at risk of local extinction. Plants are projected to be particularly badly hit, because they are often unable to adapt quickly enough to a changing climate.
Dispersal can make a massive difference: Some species may be able to survive by tracking their favoured climatic conditions and dispersing into new areas. However, without the ability to disperse, the proportion of species exposed to local extinctions at a 2°C global temperature rise increases from 20 per cent to around 25 per cent. Under a worst-case scenario of no dispersal at 4.5°C, that figure jumps from 40 per cent to 50 per cent.
Conservation efforts are crucial: They are important for dealing with the existing pressures – such as habitat loss, poaching and unsustainable harvesting – but they can also help species to adapt to climate change. Redoubled local conservation efforts will be needed to protect and restore biological corridors that support dispersal, and to secure those areas that will remain as suitable habitat – known as “refugia” – even as temperatures rise.