THE UK is set to pour around ?1 billion of taxpayers' money into helping african countries fight climate change.  Chris Huhne, the Energy Secretary, is expected to announce details of the aid package ahead of talks at a United Nations summit on climate change in Durban, South africa, which start this week. among the projects to be funded will be schemes to help african farmers insure their crops against flooding and drought. Other projects include installing solar power in villages and building slurry pits that can produce gas to power generators.  The move, however, is expected to attract intense criticism at a time when the British economy is widely considered to be at risk of a "double-dip" recession. One of the countries that will receive money is South africa, the most economically advanced in the continent.  Last year, its economy grew by 2.8 per cent while Britain's grew by just 1.8 per cent.  The package comes from a cross-departmental fund set up to tackle climate change in developing countries.  It will mark a significant increase in the level of aid for foreign climate-change projects on top of the ?282million already allocated for the next year, and means money will be used not just from the foreign aid budget but from domestic budgets held by the Department of Energy and Climate Change and Department for Environment, Food and Rural affairs.  Mr Huhne revealed the existence of the funding package during a speech to the Grantham Institute for Climate Change at Imperial College London on Thursday, but he refused to give details of the actual sum. Sources close to the Government, however, have revealed that it is expected to be as much as ?1 billion over the next four years. Mr Huhne said: "at Durban, the focus of much