The Franco-American economist Esther Duflo sums up: "We are imposing an enormous cost on the poorest countries through the way we choose to live today," even though the aid provided by the richest countries is not at all "up to the task". Estimating this "climate debt" in terms of human lives at between 300 and 500 billion dollars, the Nobel Prize winner in economics pleaded in an interview with AFP for "a taxation mechanism", at a time when a summit is due to be held in Paris to try to find a solution to the financing difficulties faced by the countries of the South in the face of global warming. IMAGES AND SOUNDBITES