Humans have a responsibility to care for the earth. Wise use of our resources is essential, but it is possible to be unwise and irresponsible in more than just one way. Those seeking power have learned to exploit fear to achieve their ends, and this happens in the realm of environmentalism as well. I marvel at the scientific unsoundness of the many fear-based decisions that are made in the name of saving the earth (the solution - surprise! - is usually to give a handful of wise, humble politicians more power and money).
An interesting article on this topic is "Science, Politics and Death" by Arthur B. Robinson & Jane M. Orient. It makes some salient points about global warming and other hot areas of environmental debate.