Although climate fluctuations are normal, in the absence of a catastrophic event (e.g. the meteor that is proposed to have been responsible for the demise of the dinosaurs) it is the rate of the change occuring now that is most alarming, and which points unquestionably to a human involvement. I didn't expect to see these changes, especially of this magnitude, in my own lifetime, but they're here and accelerating.
The cost of doing nothing will be far greater in human terms than the cost of taking steps to slow the process, if it isn't already too late.
It is also unrealistic to suggest that we simply "sit back and enjoy it". We're not going to enjoy this. This is not going to mean simply an across the board increase in temperature of a couple of degrees, equally around the world. Air temperature change will be accompanied by changes in ocean temperature, which in turn will decrease ocean salinity, for instance. All organisms that have evolved in the current status depend on that microenvironment to live. Plankton that thrive in the microenvironment feed a wide variety of small fish, for example. Those fish comprise the diet of larger fish, and on and on. If the salinity is changed, most of that vegetation, and everything that depends on it to live, will not survive. New organisms will not spring up immediately to replace them; that will take far longer than we have to live.
Another change occasioned by alterations in northern ocean (Atlantic in this case) salinity, and temperature, will be the Gulf Stream, which crosses the Atlantic from southwest to northeast, warming Europe and providing the climate and humidity that the crops in that region depend on. The (still) colder and less salty water from melting polar ice will divert the flow of the Gulf Stream from its present course, in effect stranding the continent from its warming influence. Warmer global temperatures are not expected to compensate for that. So Europe is likely face some very difficult problems in feeding its population. Similarly, the estimates of water levels world wide are estimated to rise alarmingly; estimates vary but all but the lowest will undoubtedly flood coastal areas, making many large urban centers uninhabitable.
Changes already appear to be taking place in arid and desert regions; you'd think that with more water available there would be more rainfall, and that may occur in localized areas, but there's an increase in the desertification of a large arid region in central China, and here where I live we're beginning to face some serious water crises as well. A number of predictions have been made about increased storm activity and severity. I don't understand enough about that to make any sort of statement other than to report that.
The consequences of climate change go far beyond those above. This is just a small sample. There are some things that we can do. Many involve simply being more conscious of conservation of our resources. Many involve alternative, renewable energy sources. Many involve taking a good hard look at the way that we live and trying to be more responsible to our habitat so that we can can leave a habitable planet behind for those who will follow us.
