The Forces Driving Rapid Climate Change
Predicting weather is not an easy task. Winds and rains are fickle and subject to a wide range of random variations. Predicting how climate is going to change over time is an even more daunting task.
Information based on: Rizza,SOE 95-2. Environment Canada, 1995
The relationship between sun, earth and atmosphere is exceedingly complex. For example, increased radiation from the sun trapped by more greenhouse gases in the Earth's atmosphere make the Earth's mean annual temperature rise. This causes more water to evaporate from the oceans, leading to more cloud cover. During the day, having more cloud cover means more of the energy back into outer space than does a cloudless sky. Thus these clouds have a cooling effect. But clouds at night act as a blanket helping to hold the Earth's surface heat in, thus having a warming effect. The net effect of the two opposite effects is not yet fully understood!
Living plants also contribute to the dynamic climatic cycles. During warming cycles boreal forests move northward, conquering areas that were previously treeless tundra, thus adding to global warming. There are other feedback sub-systems that are part of the complex climate dynamics, including absorption and fixation of carbon by shelled creatures of the sea.
Existing forest and grassland boundaries (TOP MAP) and change in the extent of these ecosystems (BOTTOM MAP) resulting from global warming and associated climate shifts if the atmospheric CO2 level doubles--projected to occur around the year 2100 if current emission rates are not stablized.
As computers get more powerful and models get more sophisticated--in a decade or so--climatologists predict that we will know with much more certainty the rate of global warming and by how much it is increasing, how much human activities are contributing to it and more accurately what negative climate shifts will ensue that will negatively affect us and our children.
But even in our ignorant state now and with conservative estimates the changes are going to be staggering. The ultimate fear is -- by the time we really know what is happening we may have launched ourselves past a point of no return where cutbacks in greenhouse gasses no matter how steep will not be able to avert catastrophic changes.
The most rapidly changing variable affecting climate on a global scale today is the increase in greenhouse gasses accumulating in Earth's atmosphere. There are many of these being introduced by human industrial activities. They include carbon dioxide (CO2), methane (CH4), nitrogen oxides (NOx) and the notorious chlorofluorocarbons(CFCs) that also destroy high level ozone that protects the Earth's surface from the sun's high energy ultraviolet sunlight radiation.
But by far the greatest contributor is carbon dioxide. Even when fossil fuels are burned cleanly, there is no way to escape producing CO2. Greatly curtailing the use of fossil energy sources (coal, oil, and natural gas) will go a long way to putting the brakes on global warming!
