Question: How does global warming affect tropical rainforests such as the Daintree Rainforest in Northern Australia? Answer: One effect are the trees in the rainforest are now giving out more carbon dioxide than they take up. Rainforests used to be a large sink for carbon dioxide, and now this is not happening less. Scientists are finding out that the increase in carbon dioxide in our atmosphere is causing there to be a different range of plants in the rainforests than there used to be. The deforestation of tropical rainforests is a major cause of climate change. Tropical rainforest deforestation is an important contributor to global warming. Cutting down of living trees reduces the amount of photosynthesis.