Climate change will soon threaten many more species with extinction

Dr Tony Martin In the Arctic tundra, climate change will cause dramatic losses in waterbird breeding habitat Zoom In

Climate change will reduce, and force shifts in, the ranges of many species. Many will not be able to move fast enough, or in concert with other species. This will result in extinctions. Whether we lose a few species or huge numbers will depend critically on the degree of warming. We must act now to minimise this.

Many species will suffer from range shifts and losses

Modelling studies show that the ranges occupied by many species will become unsuitable for them as climate changes. The climate space that is suitable for particular species may shift (in latitude or altitude: see box 1), contract (boxes 2 and 3), or even disappear (box 4). Species whose climate space both contracts and shifts substantially will be of particular concern (box 5).

Climate change will result in many extinctions

Studies suggest that many species will not be able to keep up with their changing climate space. As species move at different rates, the community structure of ecosystems will also become disrupted. Both local and global extinctions are likely, even of species currently considered safe. One recent global study estimated that 15–37% of species could be committed to extinction by 2050 as a consequence of climate change. The most susceptible species will be those with restricted ranges, bounded distributions (on the edges of continents, mountain-tops or small islands), specialised habitat requirements, poor dispersal abilities or small populations. While bird species differ greatly in dispersal abilities, most are relatively mobile compared to other organisms—which will be impacted even more severely.

The extent of warming will be critical

The size of the extinction crisis caused by climate change will be directly related to the degree of global warming (box 4). A global average temperature rise of 2°C in the next century will lead to numerous extinctions, but leave open some practical management options for the conservation of biodiversity. Temperature rises beyond this level are predicted to lead to catastrophic extinction rates, with few management options and a bleak future for both biodiversity and people.

Boxes: case studies and scientific analyses

Download SOWB pp.48–49 (PDF, 371 KB) containing the following:

1. In Mexico, climate change may lead to habitat becoming unsuitable in large parts of the range of Worthen's Sparrow
Modelled future distributions of Worthen's sparrow

2. In the Arctic tundra, climate change will cause dramatic losses in waterbird breeding habitat
The Dunlin is predicted to suffer extensive loss of its tundra breeding habitat

3. In southern Africa, the range of Cape Longclaw is predicted to retreat to upland areas
Modelled future range of Cape Longclaw

4. The number of montane endemic birds that go extinct in Australia will depend on the degree of warming from climate change
Modelled range loss of Australian mountain endemics

5. In Europe, species with ranges that both contract and shift are likely to be most at risk
The percentage overlap and size change of the potential future ranges of ten bird species endemic to Europe, under a climate change scenario