Delegates from across the world are meeting in Durban, South Africa, to review prospects for the Kyoto Protocol, parts of which are set to expire.
U.N. Secretary-General Ban Ki-moon said more work was needed to slow the pace of deforestation.
"I am encouraged to see that forest countries are acting to reduce deforestation and that donor countries are pledging to support these activities," he said in a statement. "Yet, forests continue to disappear at an alarming rate. We must do more and with a greater sense of urgency."
The United Nations through its Collaborative Program on Reducing Emissions from Deforestation and Forest Degradation aims to put a monetary value on the carbon stored in forests and offer incentives and help developing countries invest in a low-carbon economy.
Using satellite data, the United Nation's Food and Agricultural Organization concluded forested land was lost to other uses at an annual rate of 4.9 million hectares from 1990-2005.
The FAO found the rate of deforestation accelerated from 2000-05 when compared with 1990-2000.