IUCN's Global Species Programme, in collaboration with IUCN's commissions and members, is working hard to ensure that the complexities of the impacts of climate change on species are appropriately considered in conservation activities, and that human responses to climate change consider and address how they can minimise the impacts to the biodiversity upon which they depend.
Anthropogenic climate change is increasingly being acknowledged as one of the greatest threats to biodiversity and human societies alike. Significant changes in the climate system are already being observed, and the most recent projections of future climates suggest combinations of increased average temperatures; changes in the global water cycle; increasing ocean acidity and rising sea levels; continued loss of polar ice and montane glaciers; and altered weather patterns, including changes in the frequency and severity of extreme events.
Such changes have necessitated reconsideration of how we think about species extinctions, and even of how we approach conservation.
The ways in which climate change is expected to affect species are multiple and complex, but are generally thought to include:
- Loss or degradation of important habitats and microhabitats.
- Changing of environmental thresholds e.g. temperature, water availability/quality beyond those that a species can tolerate.
- Loss of important interactions between two unrelated species, or the arrival of new, negative ones e.g. disease.
- The disruption of environmental cues (e.g. for breeding or migration).
- The direct loss of individual organisms, or even populations, as a result of extreme events.
Species affected in the above ways will either need to move to new, more suitable locations or to somehow adapt to change at their current locations. Species that are unable to do this are likely to perish, and in some cases may become globally extinct.
IUCN is continuing to develop and apply their unique 'trait-based' approach to assessing species' vulnerability to climate change (see diagram below), and promoting the use of its outputs when developing or revising species conservation strategies.
Working in many corners of the globe, IUCN has been applying these methods to an increasing range of species, including vertebrates, invertebrates and plants, and have aimed to increase the capacity of stakeholders at many locations to interpret and act on their findings, or even to conduct species vulnerability assessments of their own.