On the other hand, the Outlook offers a message of hope. The options for addressing the crisis are wider than was apparent in earlier studies. Determined action to conserve biodiversity and use it sustainably will reap rich rewards. It will benefit people in many ways - through better health, greater food security and less poverty. It will safeguard the variety of nature, an objective justified in its own right according to a range of belief systems and moral codes. It will help to slow climate change by enabling ecosystems to absorb and store more carbon; and it will help people adapt to climate change by adding resilience to ecosystems and making them less vulnerable.

Taking actions to ensure the maintenance and restoration of well-functioning ecosystems, underpinned by biodiversity and providing natural infrastructure for human societies, can provide economic gains worth trillions of dollars a year. The latest science suggests ever more strongly that better management, conservation and sustainable use of biodiversity is a prudent and cost-effective investment in social and economic security, and in risk reduction for the global community.

This Outlook shows that efforts to date have not been sufficient to reduce significantly the rate of biodiversity loss and analyses why; it assesses the potential for long-lasting or irreversible ecosystem changes to result from current trends and practices; and it concludes that concerted and targeted responses, with action applied at appropriate levels to address both direct pressures on biodiversity and their underlying causes, can in the long term stop or even reverse the continued decline in the variety of life on Earth.

The action taken over the next two decades will determine whether the relatively stable environmental conditions on which human civilization has depended for the past 10,000 years will continue beyond this century. If we fail to use this opportunity, many ecosystems on the planet will move into new, unprecedented states in which the capacity to provide for the needs of present and future generations is highly uncertain.

Box 1: Biodiversity, the CBD and the 2010 target

The word biodiversity, a contraction of the synonymous phrase 'biological diversity', is defined by the Convention on Biological Diversity (CBD) as 'the variability among living organisms from all sources including, inter alia, terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are part; this includes diversity within species, between species and of ecosystems'. This is the definition used throughout this document. The CBD is one of the three "Rio Conventions", emerging from the UN Conference on Environment and Development, also known as the Earth Summit, held in Rio de Janeiro in 1992. It came into force at the end of 1993, with the following objectives: "The conservation of biological diversity, the sustainable use of its components and the fair and equitable sharing of the benefits arising out of the utilization of genetic resources, including by appropriate access to genetic resources and by appropriate transfer of relevant technologies, taking into account all rights over those resources and to technologies, and by appropriate funding." There are currently 193 Parties to the Convention (192 countries and the European Union). In April 2002, the Parties to the Convention committed themselves to achieve by 2010 a significant reduction of the current rate of biodiversity loss at the global, regional and national level as a contribution to poverty alleviation and to the benefit of all life on Earth. This target was subsequently endorsed by the World Summit on Sustainable Development (the "Rio + 10" summit) in Johannesburg, 2002, and by the United Nations General Assembly. It was also incorporated as a new target under one of the Millennium Development Goals - Ensure Environmental Sustainability. The 2010 biodiversity target is therefore a commitment from all governments, including those not party to the CBD.