What do Amazonian Dark Earths or terra preta have to do with the Global Climate and what lessons can they teach us about sustainable development and human/environment interaction?

We currently know little about Amazonian Dark Earths. They are ubiquitous prehistoric human-made soils that store significant amounts of carbon and are thus a global carbon sink. The soils are exceptionally fertile and resilient, standing out from the predominantly infertile Amazonian soils. Some scientists have already suggested that we could create terra preta and develop more productive and sustainable agriculture in the tropics. Most importantly, prehistoric native Amazonians practiced a more sustainable, environmentally-friendly form of food production that once supported dense populations and complex societies in the Amazon Rainforest.