(File photo) Shongwe said predictions for southern Africa saw the frequency of cold days significantly decreasing.

Paris - Lawsuits related to climate change have surged in recent years, although many have been thrown out, some are focussed on regulatory issues and the key question of liability remains undetermined.

- In 2010, 132 climate-related cases were filed in US courts, almost triple the tally of 48 for 2009. In 2003, just a single case was filed.

- Litigation outside the US is at a far lower level, but slowly growing. There have been at least 67 cases in the past decade, 32

of which have been filed over the past three years. In 11 cases, appeals have been filed or the outcome is unknown. Jurisdictions comprise Australia, Britain, Canada, the Czech Republic, France, Germany, New Zealand, Nigeria and the European Union.

- A quarter of US lawsuits filed since 2001 have been by green groups against coal-fired power plants. Many other suits, filed by activists but also by industrialists, are requesting adjudication on regulation of carbon dioxide emissions by the Environmental Protection Agency (EPA).

- In Europe, climate cases have focussed especially on corporate appeals against Europe's emissions trading system. A big case was France, where a law proposing a carbon tax was annulled.

- Other areas of litigation include access to corporate data on emissions, the impact on endangered species and compensation for climate-related damage. Unexplored areas include state-to-state litigation, the legal status of “climate refugees” and whether island states that become unhabitable because of rising seas should retain their seat at the UN or their rights to the sea bed.

- Compensation claims could theoretically lead to bills in the hundreds of billions of dollars, for those who extract fossil fuels, sell them and burn them. In the courts, these cases have run into uncertainty about judicial competence and legal responsibility. Two major cases have reached the US Supreme Court. -