Climate change primer

As I mentioned in my first post, those of us who will be riding the People's Climate Train are headed for NYC to participate in the People's Climate March, an effort to make concern about climate change loud enough and visible enough so that world leaders, who will be meeting at the United Nations on Sept. 23, get the message that they MUST create a strong international agreement to take whatever steps necessary to reverse the growth of emissions of greenhouse gases so that catastrophic climate disruption can be averted. What follows is a simplified explanation of the basic issue.  

 Currently, the average surface temperature of the earth is relatively hospitable to human life, as well as to the life of  the other creatures with which we share the earth, as has been the case for several million years. That temperature, we now know, is sensitive to the levels of certain gasses in the atmosphere, and has fluctuated with those levels over the millenia. These are called “greenhouse gasses”, because, like the transparent surface of a greenhouse, they allow most of the radiant energy of the sun’s rays to reach and warm the surface of the earth, but they then trap the infrared rays radiated back out by the earth rather than allowing them to escape back into space, thus keeping the earth warmer than it would be otherwise. To a certain extent this is a good thing, because without these greenhouse gasses the earth would be too cold to support life as it currently exists. However, too high a proportion of greenhouse gasses in the atmosphere will cause the earth to be too warm to support life as we know it.

 Over billions of years, the earth has evolved a system of regulating the amount of greenhouse gasses in the atmosphere. One of those is carbon dioxide. Certain processes, such as decaying vegetation, fires, and animal respiration release carbon dioxide into the atmosphere.  Through photosynthesis, however, plants “breathe in” carbon dioxide, they separate the carbon from the oxygen, they turn the carbon into new vegetable matter, and “breathe out” oxygen back into the atmosphere, which we then breathe in to start the cycle again. Over time, a certain equilibrium between the creation and consumption of carbon dioxide has resulted in the climate we currently enjoy.

  People used to think (and some still do) that there is no way that human activity could have a significant effect on a system as massive as the earth, but three factors belie this belief:  one is the increasing power of human technology; another is continuing population growth;  the third is the delicate balance of the ecological system within which we live.  The tools we invented, which originally gave us an adaptive advantage but did not endanger the ecosphere at first because they were not so powerful and we were not so numerous, have become so sophisticated and powerful that our use of them has now become maladaptive. We now see that our activity does, in fact have significant impacts on the global ecosystem. Those impacts are threatening to cause the collapse of that system on any number of fronts, and of course if it does collapse it could well mean the end of us as it has already for numerous other species. 

It is not just that the earth is warming that is the problem. Just as big a problem is that all the weather patterns-- amount and distribution of precipitation, prevailing winds, season length and rapidity of changes, etc.-- upon which our global food supply depends is being disrupted. We are so dependent on the global system of industrial food production and distribution, which is in turn dependent on a stable and dependable climate, that significant disruption of those patterns can rapidly lead to a worldwide food crisis, followed by mass migration of populations and widespread violence. The violence in Syria was precipitated by a severe, extended drought in the northern rural areas of the country which forced millions of rural dwellers to urban areas seeking relief and employment.

The question is whether we will adapt and change our behavior rapidly enough so that the ecological balance on which our lives depend can be preserved for future generations of humans, or whether it will be left to other species to pick up where we left off once we are gone. That is very much an open question. The People's Climate March-- and solidarity events and activities that are happening all over the world at this point (see http://peoplesclimate.org/join-an-event/) is one effort in a growing movement weigh in on the side of future generations of humans. Not everyone can travel to New York to directly participate in the march, but everyone can do something to become part of the movement.