A leading conservation group called for deep cuts to greenhouse gas emissions by 2050 and said biodiversity losses pose a greater risk to mankind that current financial problems.

"The clear message coming out of this meeting is that biodiversity underpins the well-being of human societies and their economies," said Julia Marton-Lefèvre, director general of the International Union for Conservation of Nature, in a statement at the end of a 10-day IUCN congress in Barcelona.

"But conservation can only succeed if we attack the underlying causes of biodiversity loss, and action is taken at the same time to reduce the impacts of that loss," she said.

The IUCN, formerly known as the World Conservation Union, said it is calling on the United Nations Climate Change Summit scheduled to meet in Poland in December to implement more specific goals for cutting carbon dioxide emissions. The IUCN said a 50 to 85 per cent cut in CO2 emissions by 2050 and actions on biodiversity and ecosystem services are needed.

The group also called for improved guidelines and standards for biofuels to limit their potential impacts on nature and people. While biofuels help cut greenhouse gas emissions, dedicating land to growing biofuel crops can impact wildlife habitats.

More than 8,000 conservation specialists gathered at the meeting of the IUCN, formerly known as the World Conservation Union. The group began their meeting with the release of the first review of the world's mammals in more than a decade, which found that close to a quarter of mammal species are threatened with extinction.

The group said in a statement that while the news around the world focused on a deepening financial crisis, the cost of biodiversity losses are greater and "in many cases, they are irreparable."