"Unlike many reports from scientists, this report gives very clear recommendations for what the international community and nations themselves must do to mitigate and adapt to climate change", said Peter Raven, a leading expert in biodiversity and former President of Sigma Xi, a 60,000-member scientific research society. Confronting Climate Change: Avoiding the Unmanageable, Managing the Unavoidable was released by the Scientific Expert Group on Climate Change and Sustainable Development at a panel discussion organized by the United Nations Foundation and Sigma Xi at UN Headquarters on 27 February 2007, where the co-authors outlined the sweeping changes needed to deal with climate change.

From left: Peter Raven, Timothy Wirth, John Holdren UN photo/Ryan Brown

"Climate change is real and it is already happening", said John Holdren, professor of environmental policy at Harvard University. "If global carbon levels continue to increase as they have, the earth's climate will become unmanageable and intolerable." He offered strategies to mitigate the effects of climate change, mainly through limiting the amount of carbon released into the atmosphere by, among others, promoting energy efficiency, stopping tropical deforestation, expanding renewable sources of energy, such as wind and solar energy, and making fossil-fuel powered energy plants as clean as possible. The report says that holding global increases in temperature at between 2 and 2.5 degrees Celsius is required to mitigate the most serious effects of climate change, and this requires global carbon dioxide emissions to peak no later than 2015 to 2020 and decline to one third of that value by 2100.

Rosina Bierbaum UN photo/Ryan Brown

"Hundreds of animal species have already changed their ranges, and the ecosystems are being disrupted due to climate change", said Rosina Bierbaum, Dean of the University of Michigan's School of Natural Resources and Environment. Floods, droughts and storm intensity have increased in recent decades, and most of the negative effects of climate change will be felt in the developing world, she said, adding that tens of millions of "climate refugees" will flee rising sea levels and storm surges. Adapting to climate change contained "many win/win solutions; we can create economic opportunities, reduce global poverty and achieve sustainability at the same time". Immediate steps to begin the adaptation process included conducting regional vulnerability assessments to identify challenges and priorities, and avoiding development in coastal areas that are less than one metre above high tide, she said.

As for the United Nations, Ms. Bierbaum said that it should help developing countries to finance and deploy energy efficient technologies, incorporate adaptation into UN framework conventions on climate change and related environmental organizations, and develop a framework for climate change and sustainable development to succeed the 166-member Kyoto Protocol, an international agreement aimed to reduce carbon emissions that is set to expire in 2012.

Following the steps prescribed in the report would also lead to the achievement of the Millennium Development Goals, the eight targets ranging from halving extreme poverty to halting the spread of HIV/AIDS by 2015, Mr. Raven said. Not following the steps would make the goals "much harder, if not impossible, to reach".

The report points out the enormous reductions in greenhouse gases that can be achieved in the transport sector, which is responsible for one quarter of carbon emissions from energy worldwide, through the "supply side" options, such as switching from oil to natural gas or biofuel, and the "demand side" solutions, which make transportation more efficient. Demand-side solutions include encouraging shorter trips for commuting, shopping and recreation through smart urban planning, switching from private vehicles to cleaner modes of transport like bicycles, buses and regional trains, and increasing the number of passengers per automobile. Mr. Holdren suggested taxing automobiles that have low fuel efficiency and providing financial rewards for buying cars that use less fuel.

The report also champions the construction of "climate resilient cities", which Mr. Holdren identified as cities that produce low per-capita emissions and are able to manage weather-related events. A climate resilient city also has a reliable supply of potable water, given that water will likely become scarcer as weather patterns change. Such cities would likely be more compact and densely populated, with large open spaces between them--areas that can be used to absorb the brunt of storms and hold water, Mr. Holdren said.

"This group views the climate challenge as an enormous opportunity for very significant economic change and for dealing with the poverty issue", said Timothy Wirth, President of the United Nations Foundation. He called on the UN Secretary-General to "lead the world to a consensus discussion and develop a strategy to be implemented over the next 50 years", and that "the faster we get at it, the easier it's going to be to adapt".