Two panels were convened entitled, "Rising to the Challenge: Partnerships on Climate Change" and "Responding to a Multifaceted Challenge: The UN at Work." [Watch Webcast: Panel 1, Panel 2]

Featured speakers include New York City Mayor Michael Bloomberg, actress Daryl Hannah and Sir Richard Branson, Founder and Chairman of the Virgin Group.

Mayor Bloomberg detailed the metropolis' plans to reduce its carbon footprint by nearly one third by 2030.

"Reducing your carbon production increases the social and economic well-being of your people," said Mayor Bloomberg, citing such examples as New York's taxis converting to hybrid cars, congestion pricing to reduce pollution and the planting of 1 million trees over the next decade to capture carbon dioxide. [Watch Bloomberg Webcast]

Mr. Branson appealed for concerted global action to face the challenges posed by climate change. During a press conference on Monday, Mr. Branson proposed the creation of an "international war room," a politically-independent gathering of scientists, economists and others to catalyze the public sector, businesses, non-governmental organizations and governments to act on a large scale. [Watch Branson Webcast]

"The war room will be a unique combination of entrepreneurial muscle, the best possible data and the power to mobilize resources and influence policy," he said.

Mr. Branson, whose company has offered a $25 million prize to encourage scientists and inventors to figure out how to extract carbon from the environment, also underscored the necessity of finding a technical solution to the issue of global warming.

Meantime, the top UN climate change official urged increased financial investment and technological innovation to tackle the issue.

Yvo de Boer, Executive Secretary of the UN Framework Convention on Climate Change (UNFCCC), said that they are "the glue that connects action on the part of developed and developing countries." [Watch de Boer Webcast]

Secretary-General Ban Ki-moon, who just returned from Chicago where he encouraged hundreds of business leaders to embrace 'green economics,' also called on developed nations to lead the effort to combat global warming in order to spur action by poorer ones. [Watch Secretary-General Webcast]

"The more ambitious the commitments by developed countries, the more actions we can expect from developing countries," he stated. "The more developing countries engage, the more ambitiously the developed countries will commit."

The Secretary-General urged participants to build on the momentum generated by the breakthrough at last December's landmark UN Climate Change Conference held in Bali, Indonesia, where ended with 187 countries agreeing to launch a two-year process of formal negotiations on a successor pact to the Kyoto Protocol, which expires in 2012.