I see what you're saying OE...and it is a popular point....the earth is going to do what she is going to do...or as I've heard some say..."the earth will take care of herself." But, I ask, is the argument whether we have power over the earth or the power to influence the earth? I would argue that the concept of global warming (or global climate change) is that it is a point of power to influence, not power over. If the sun and earth want to do something, they will do it - we have little power to change that. However, it is obvious we have power to influence the earth's tendencies. We can seed clouds to cause rain - or prevent it in other places, with some degree of success. We have raised the local temperatures of specific areas by building cities there and causing urban heat traps. We have caused the rain's pH to change significantly enough in some areas to kill plant life through acid rain.
We certainly can and have influenced the earth's otherwise natural tendencies. The impacts are small on the scale of ice ages, plate tectonics, etc. When it comes to these issues, we currently have little or no power to influence them. The earth's climate will cool again - and we will have an ice age (unless we find a way to install a giant lens in space). However, that doesn't mean that man can have no influence over otherwise natural tendencies on time scales shorter than these very slow dynamics.