To make a model that can accurately predict the impacts of climate change, it's crucial to know whether tropical forests will in fact be sinks for carbon dioxide---net reducers of CO₂ in the atmosphere---or whether they'll be sources, releasing more CO₂ than they absorb. The research of Deborah and David Clark, at La Selva in Costa Rica, hints at the idea of rainforests as CO₂ sources, a scary proposition that could speed up the effects of global warming. Armed with decades of data, the Clarks are now showing that enough global warming will slow the growth of tropical trees, which could cause rainforests to emit more carbon dioxide than they soak up, and by century's end, trees in the tropical forests could die. Instead of saving us from the greenhouse effect, the world's rainforests could contribute to it. This thesis includes a reported work of journalism about the Clarks' research, as well as thoughts about the potential for a longer body of work on this topic. It concludes with observations about the relationship between scientists and journalists.