Climate change impacts biodiversity through complex interactions among species and between species and their habitats.

The structure of both habitats and their ecological functions will change in a new climate regime. But the movement of species into or out of a community will also affect both the physical elements of the ecosystem and other species. Changes to local conditions and resources will thus influence a species' ability to survive. And if a species can no longer survive in an ecosystem, it has two choices. If it can disperse rapidly enough and an accessible and suitable alternative habitat exists, it can relocate. Or it can gradually disappear in different locations and eventually go extinct.

Whether directly or indirectly, climate change can produce a variety of effects on species populations, including:

- distribution changes: due to habitat loss and depending on species dispersal ability;

- phenological changes: changes in timing of life stages;

- ecological changes: mismatching of species life-cycle events and food sources, decoupled predator-prey relationships, new invasions and spread of already established invasive alien species.

Under a new climatic regime, therefore, individuals of some species may be able to colonise new, more suitable areas. But a variety of factors could limit the availability or accessibility of such areas, including land use changes and fragmentation, hydrological changes and nitrification, and sea level rise. New species assemblages and changes in the relative abundance of populations are expected in some ecosystems. Changes in species composition, habitat structure and ecosystem functioning will be noticed and, in combination, may affect the resilience of ecosystems and the services they deliver to humanity.

Further reading:

Selected links:

European Climate Adaptation Platform (CLIMATE-ADAPT)

Climate Change indicators

Adaptation support tool

The CLIMSAVE project

EC Climate Action

EC Global Climate Change Alliance (GCCA)

European Topic Centre for Air Pollution and Climate Change Mitigation (ETC/ACM)

European Topic Centre on Climate Change impacts, vulnerability and Adaptation (ETC/CCA)

EEA Climate Change data centre

Intergovernmental Panel on Climate Change (IPCC)