The impacts of climate change on nature

Animals and plants under increasing threat

Human-induced climate change has already sounded the death knell for its first victims.

The golden toad (Bufo periglenes) and the harlequin frog (Atelopus varius) of Costa Rica have disappeared as a direct result of global warming. Species are under threat in more than one way.

Irreversible changes to ecosystems and animals

As climate change wreaks its havoc across the globe, ecosystems could disappear altogether, or they may undergo serious and irreversible changes, such as those happening to coral reefs.

Warming affects cold seas and polar communities as well:

  • Polar bears in the Hudson Bay area of Canada are losing weight and getting less fit because the ice breaks up 2 weeks earlier in spring, robbing them of 2 weeks’ hunting.
  • Fish stocks that used to stay in Cornwall in south England have moved as far north as the Shetland Islands.

As average temperature increases, optimum habitat for many species will move higher up mountains or further towards the Poles. Where there is no higher ground or where changes are taking place too quickly for ecosystems and species to adjust, local losses or even global extinctions will occur.

Seasons are changing

Satellite maps showing of Koyukuk River, Alaska showing the four seasons. 
	© MODIS Instrument on the Terra Satellite operated by NASA
The seasons change in Huslia, Alaska on the bank of the Koyukuk River.
© MODIS Instrument on the Terra Satellite operated by NASA

Rapid temperature changes affect the seasons, causing variations in season length.

Changes such as shorter winters can lead to mismatches between key elements in an ecosystem, such as feeding periods for young birds and availability of worms or insects for food. It also impacts on farmers’ growing seasons.

Climatic records put together with long-term records of flowering and nesting times show clear warming trends.

In Britain flowering time and leaf-break records date back to 1736, thus providing solid evidence of climate-related changes. Long-term trends towards earlier bird breeding, earlier spring migrant arrival and later autumn departure dates have been observed in North America, along with changes in migratory patterns in Europe.

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