Ecosystems and biodiversity underpin biological productivity and socio-economic development, through the provision of many goods and services to people and industry. These ecosystem services include food, water, timber, fuel and fibre; supporting services such as soil formation, photosynthesis and nutrient cycling; and regulating services that affect climate, floods, disease, waste and water quality, helping people to adapt to climate change. Humans are fundamentally dependent on the flow of these ecosystem services.
Climate change threatens these basic elements of life. For example it is predicted that melting glaciers will initially increase flood risk and then strongly reduce water supplies; declining crop yields, especially in Africa (where over 70% of workers rely on small-scale farming that is dependent on direct rainfall) could result in an additional 80-120 million people at risk of hunger; rising sea levels will result in tens to hundreds of millions more people affected by flooding each year; changing climatic conditions will result in geographic shifts in human diseases; and ocean acidification, a direct result of rising carbon dioxide levels, will have major effects on marine ecosystems, with possible adverse consequences for fish stocks.
Developing countries need extra resources to allow them to safeguard and manage their assets sustainably. New policies are needed to integrate options for meeting biodiversity, climate and sustainable development objectives.
These direct and indirect impacts of climate change are of central concern to BirdLife's objectives and targets, in terms both of biodiversity and of human development.
Even if the most effective measures were taken now without delay, a certain degree of rapid and significant climate change is already unavoidable. In order for people and nature to come well through this unprecendented crisis it is essential to increase the ability of ecosystems to adapt, and to accommodate the need of species and habitats to move into areas with more suitable climatic conditions.

Climate change impacts including droughts, crop failure, flooding, sea-level rise and extreme weather events are already being felt across the world, with the poorest people and vulnerable ecosystems hit hardest.
There is an increasing weight of scientific evidence that observed changes in climate have already adversely affected biodiversity at the species and ecosystem level, and current levels of climate change are modest compared to most projections. Plant and animal ranges are shifting poleward and upward, and studies suggest many species will not be able to keep up with their changing climate space.
One global study estimates that 15–37% of species could be committed to extinction by 2050 as a consequence of climate change; another that each degree of warming could drive another 100-500 bird species extinct. Temperature rises beyond 2 °C are predicted to lead to catastrophic extinction rates, with few practical conservation options left.
Over the past 50 years, humans have changed ecosystems more rapidly and extensively than during any comparable period of time in human history, largely to meet rapidly growing demands for food, fresh water, timber, fibre and fuel. The result has been a substantial and largely irreversible loss in biodiversity. Climate change exacerbates these impacts.
Impacts include increased extreme weather (floods and droughts), the retreat of mountain glaciers, the thawing of permafrost, later freezing and earlier break-up of ice on rivers and lakes, lengthening of mid- to high-latitude growing seasons, poleward and altitudinal shifts of plant and animal ranges (resulting in declines in some plant and animal populations, and the potential extinction of species where no such shift in range is possible) and phenological changes, such as the earlier emergence of leaves and insects and the timing of migration and breeding of species, usually genetically 'programmed' to coincide with optimal climatic circumstances and hence food availability. Adapting to a changed climate requires evolutionary change which can take a very long time. Very rapid climate change as the one we are currently witnessing could mean that many species will fail to adapt and face massive starvation and breeding failure.
These and other problems may lead to further declines in bird populations with currently common species becoming rare, and rare species disappearing from vast parts of Europe and some species risking complete extinction. The loss of species and decline of wild birds populations makes our world poorer but is also contributing to weakening the ecosystems on which we ultimately depend. Healthy ecosystems are even more important in times of rapid climate change as complex ecosystems can better buffer some of the consequences of climate change such as extreme weather events and spread of invasive species.