Our responsibilityThe fact that there have been extreme climatic changes in the history of our planet does not mean that we should disregard any impact our behaviour might have on the well-being of our planetary home. (After all, it is generally thought we put a hole in the ozone layer which a reduction in CFCs will hopefully plug.)
Whether the planet is warming is still debatable but most scientists seem to feel it is happening. How far man is responsible for the warming is also debatable, perhaps more debatable, but our production of greenhouse gases is, at the least, unlikely to help the situation and probably will aggravate it.
All that said, the real point is that humans are now such an important factor in the well-being of the planet that we have really got to start managing it. Just like anyone who is responsible for a closed, finite system, it is important to try to keep it in balance and to keep it running smoothly. Our planet is such a system. When we were just another animal, we could rely - and had to rely - on the self-regulating functions of the planet but now we are the masters, now we extract and exploit all the planet’s resources, we must learn to manage the system and accept the responsibilities that management entails.
Of course, nature may throw at us climatic changes we can’t handle – another prolonged ice age, massive increases in temperature caused by a hyperactive sun. Nevertheless, we owe it to our species to do what we can to give our children, and theirs, the best prospect of survival.