Humans have benefitted from an overall warmer climate over the past millennia. However, some now voice deep concern over the possibility of human activity leading to an acceleration of a global warming trend. There are others who refute this claim of human activity being responsible for change in climate and point to how climate has always fluctuated throughout the life of planet Earth. 1) Identify exactly what kind of human activity is being charged with contributing to the warming trend. 2) What evidence is used to refute this charge. Do you think we need more evidence before taking action to reduce CO2 emissions? Or is it better to act now to reduce CO2 emissions? What are the possible costs and benefits of each of these two strategies?