How can developing nations expect the developing nations to stop logging their rainforests, strip-mining, over-fishing, etc., if we don't give them a financial incentive to do so? Maybe developed nations should pay into a Global Environmental Tax fund annually based on their pro-rata use of global resources. The money in this fund would then be paid to developing nations for every acre of sustainable healthy natural resources they maintain.
For example, the Fund would pay Brazil for every acre of sustainable rainforest it maintains. After all, clean air and species diversity is of benefit to the whole planet -- why shouldn't Brazil be able to "sell" this resource just like some nations sell their oil? If we could make it more (or as) profitable for Brazil to keep the rainforest standing than to destroy it, this might provide a powerful incentive for them to focus on sustainability and environmental protection. Some portion of the Fund would also go toward funding a rapid-response team to conduct emergency environmental cleanup operations around the world.