Age: A GLOBAL agreement binding all significant countries, rich and poor, offers the best hope for tackling climate change, and could halve the cost of countries trying to tackle it alone, the International Monetary Fund advises. In its latest World Economic Outlook, to be released today, the IMF calls on national leaders to draft a global agreement quickly that establishes either a common tax rate on carbon, or an emissions trading scheme in which permits can be traded internationally, so …