There is ample evidence that climate change affects biodiversity. According to the Millennium Ecosystem Assessment, climate change is likely to become the dominant direct driver of biodiversity loss by the end of the century. Climate change is already forcing biodiversity to adapt either through shifting habitat, changing life cycles, or the development of new physical traits.

At the same time, biodiversity has a role to play in climate change adaptation and mitigation. For example, the conservation of habitats can reduce the amount of carbon dioxide released into the atmosphere. Currently, deforestation is estimated to be responsible for 20 percent of human-induced carbon dioxide emissions. Moreover, conserving mangroves and drought-resistant crops, for example, can reduce the disastrous impacts of climate change such as flooding and famine.

In addition, for a given ecosystem, functionally diverse communities are more likely to adapt to climate change and climate variability than impoverished ones. High genetic diversity within species appears to increase their long-term persistence. It must be stressed, however, that the effect of the nature and magnitude of genetic and species diversity on certain ecosystem processes is still poorly known. The ability of ecosystems to either resist or return to their former state following disturbance may also depend on given levels of functional diversity.