FACTBOX: U.N. panel's findings on climate change

* SOLUTIONS/COSTS

Governments have a wide range of tools -- higher taxes on emissions, regulations, tradeable permits and research. An effective carbon price could help cuts.

Emissions of greenhouse gases would have to peak by 2015 to limit global temperature rises to 2.0 to 2.4 Celsius over pre-industrial times, the strictest goal assessed.

The costs of fighting warming will range from less than 0.12 percent of global gross domestic product (GDP) per year for the most stringent scenarios until 2030 to less than 0.06 percent for a less tough goal. In the most costly case, that means a loss of GDP by 2030 of less than 3 percent.