Q 9.1 3. Over the past 100,000 years, human migrations have been significantly influenced by changes in climate. Describe two important examples of such influences.

Q 9.3 2. In what ways does deforestation contribute to the increase in greenhouse gases in the atmosphere? 9.4 1. Global warming will likely increase rainfall in some places. Why might warming cause this change? 9.6 2. It will eventually be necessary to lower CO2e emission rates below their current level. Why? 9.8 2. Because the costs of global warming are uncertain and many of the consequences are decades away, some economists argue that we should delay action at this time. What is your response to such an argument?