The document discusses the greenhouse effect and global warming. It begins by outlining the key processes in the carbon cycle, including combustion, respiration, photosynthesis, and fossilization. It then analyzes historical records of increasing atmospheric carbon dioxide concentrations. The relationship between rises in CO2, methane, and nitrogen and the enhanced greenhouse effect is explained. The precautionary principle is outlined, and its use as justification for action on global warming is evaluated. The economic costs of action are balanced against potential environmental harm. Finally, the document outlines consequences of temperature rise such as effects on arctic ecosystems and possible actions that can be taken to reduce carbon emissions and sequester CO2.