为一篇关于气候变化的文章提供三篇可靠的来源，并写出每篇来源的简要描述。
1. IPCC (Intergovernmental Panel on Climate Change) - a United Nations body that provides scientific information to policymakers regarding climate change, including its causes, impacts, and potential solutions.

2. NASA (National Aeronautics and Space Administration) - a U.S. federal agency responsible for the study of Earth and space science, which has conducted extensive research on climate change and its impacts.

3. NRDC (Natural Resources Defense Council) - a nonprofit organization that advocates for environmental protection and sustainable policies, which produces research and analysis on climate change and its impacts on the environment and human health.