What impact will climate change have on natural spaces and species?

	Photo: © Tim Zurowski/CORBIS

Climate change is already having an impact on all kinds of wildlife. Species worldwide are shifting their ranges, migrating sooner and bearing young earlier than in the past. The American robin and red-winged blackbird frequently arrive at their breeding grounds weeks earlier than they once did. The Edith's checkerspot butterfly has moved northward and into mountains as temperatures heat up further south.

In the past, climate change usually occurred at a pace that allowed wild plants and animals time to adjust. Species slowly changed their behaviour and physical characteristics in response to changing environments over thousands of years. Today, shifts in temperatures, seasons and weather are happening so fast that wildlife has little chance to adapt to changes in key habitat elements — namely food, water, shelter and space.

Climate change is also believed to be one of the factors responsible for the widespread decline of amphibians, including Costa Rica's golden toad, now feared to be extinct. In addition, coral reefs worldwide are dying off because of various factors, including unusually warm ocean temperatures, changes in storm frequencies and changes in ocean circulation. All of these conditions are thought to be the result of climate change.

Some of the most dramatic changes observed are taking place in the High Arctic. Northerners are watching in disbelief as sea ice shrinks and pulls back from the coast, new species of birds like the American robin and barn swallow settle in, unfamiliar plants, like white spruce and dwarf birch, spread over the tundra, and salmon are caught for the first time.

In the future, the fate of many species will depend on their ability to move from unfavourable climatic conditions to ones that meet their survival needs. Those that are endangered, slow-moving or isolated in fragmented areas could find themselves stranded. Physical barriers, like mountain ranges and human settlements, may prevent some species from moving to suitable habitats. Migratory species whose arrival and departure dates are no longer synchronized with the rhythms of nature may not be able to access the food sources they need to survive and the wind and ocean currents they need to travel. Some species may flourish as a result of climate change. But wild plants and animals that cannot adapt may become extinct.

Case study: Rising arctic temperatures >