Global Climate Change

Can human-induced runaway global warming turn the Earth into a boiling, sulfuric acid planet like Venus where life no longer exists?  Although not very likely, such a possibility has been raised by world famous Cambridge physicist Stephen Hawking. (1) More likely is that, over the next fifty to one hundred years, atmospheric gases generated by the burning of fossil fuels will result in major disruptions of the world's economy and the accustomed way of life of most of the Earth's inhabitants.  While nearly all Greens are familiar with the general threat posed by human caused climate change ( global warming ), not all may be aware of the full set of social and natural factors underlying this danger, nor of the various complex and largely unpredictable ways in which global warming can affect human society as this disturbing process unfolds over the coming decades.

Mechanisms of Global Warming:  The first step in understanding global climate change is to be aware of a few basic scientific facts.  Energy ( the ability to "do work", or make things happen in the physical world ) always moves from a state of high concentration to one of low energy and dispersion.  This is called the Second Law of Thermodynamics.  Following the Second Law, concentrated heat energy from the Sun radiates into cold empty space, some of it striking the Earth.  This energy warms the Earth's surface but the Earth then reflects the Sun's heat back into space.  If this were all that happened, the Earth's surface would remain as cold as that of the Moon and no life could exist.  Due to the Earth's particular evolutionary history however, a heat absorbing atmosphere has developed which trapped a certain amount of radiated heat from the Sun, keeping the planet warm and life-sustaining.  This heat trapping atmosphere originated from intense earthquake and volcanic activity hundreds of millions of years ago which resulted in massive ejections of heat absorbing carbon dioxide gas.  Resultant surface warming encouraged plant growth but this growth in turn absorbed carbon dioxide back out of the atmosphere, causing a new phase of surface cooling: this cooling was followed by an early "die off" of primitive life.  Die off cleared the way for the evolution of new, more complex life forms and thereafter a rough, dynamic, balance existed between terrestrial life and atmospheric carbon dioxide levels.

Within the anciently established and long-term CO2/heat equilibrium described above, however, shorter cyclical variations in the Earth's surface temperature have occurred over various shorter periods: 100,000-50,000 years, and less.  This alternation between warm and cool ages is attributed to slight periodic wobbles in the Earth's movement around the Sun which expose the planet's surface more or less directly to the Sun's rays.  And even with in this, there are even shorter warming and cooling periods ( Ice Ages ) of 18,000, 6,000, and 1,000 years known as Milankovich Cycles.

Given this complexity, how do we know that present global warming is related to human activity and not to some aspect of these natural causes?  Essentially, it is a matter of time scale: never before has as much warming happened in such a short time as has taken place during the modern period since 1800.  Furthermore, the cause mechanism is pretty well understood.

The Fossil Fuel Age:  Fossil fuels-coal, oil, and natural gas-were formed many millions of years ago from plant matter trapped at the bottom of ancient seas or in the earth and subjected to pressure over long periods of time.  This geological process left deposits of fossil hydrocarbons distributed irregularly under the Earth's surface: great stores of highly concentrated energy derived originally by plants from sunlight by the process of photosynthesis.  This stored energy, the result of millions of years of slow bio-chemical and geological interaction, remained untouched until the beginning of the Industrial Age.  With the coming of the modern factory and modern transportation, fossil fuels-first coal, then oil, and finally natural gas-were taken from the earth and burned for energy in the production of commodities.  This burning released stored carbon as carbon dioxide into the atmosphere, just as plants do in natural respiration.  The wild card in this process, however, is that as world industrialization proceeded millions of years of stored carbon dioxide was suddenly dumped into the atmosphere in a matter of a century.  Never before in the 3 billion year history of life on Earth had a single species ever had this effect on the planet's biosphere-atmosphere system.

Indications of Global Warming:  Analysis of ice core samples indicate that before 1800 atmospheric CO2 concentrations had remained at between 200 and 280 parts per million for the past 400,000 years.  Today, atmospheric CO2 is near 380 parts per million: in total, this amounts to a release of 270 billion tons of carbon into the atmosphere over the past 150 years ( about 3/4 of this during the past 50 years )  Paralleling this is the fact that global average temperature has risen between 0.3 degrees and 0.6 degrees C since 1860; this despite an opposite cooling effect from industrial and volcanic sulfur emissions.  This may not seem like a great increase, until one considers the amount of energy required to raise the temperature of the entire Earth's surface any amount at all. During the same period, sea levels have risen between 10-25cm as glaciers melt and warmed ocean water expands.  Most recently, studies have revealed an unprecedented increase in temperature in the Earth's upper latitudes.  This Arctic warming-which has taken place over the past 30 years-in some regions exceeds by tenfold overall global warming.  One reason for this unexpected development is probably the albedo effect, the heat reflecting power of ice in Arctic regions.  Such Arctic super-warming points to one primary fact of global climate change: that the results will be complex, "chaotic", and thus highly unpredictable, especially in regional consequences.

When it comes to climate change, complexity is the rule.  Along with rising sea levels and coastal flooding, regions that are now dry may become wet, and wet regions dry.  Vegetation and crop distribution patterns will change; as will local, long established, weather patterns.  Some plant and animal species will benefit from change, others will suffer extinction or endangerment.  It is difficult to know exactly how climate change will affect human economic activity, but the chances are the effects will be highly destabilizing. Especially when coupled with expected stresses caused by increased population and resource depletion.

Another probable consequence of carbon dioxide induced climate is that-due to the complex nature of the total change process-some areas of the globe will experience local cooling rather than warming.  To illustrate just how complex the actual process of climate change will be, some scientific models ( Manabe and Stouffer, 1995; Russell and Rand, 1999 ) predict greenhouse gases, by increasing precipitation at high latitudes, will decrease ocean salinity in the North Atlantic, and thus cause a weakening of the ocean conveyor belt which bring heat to the North Atlantic and North America.(2)  The result may be regional cooling rather than warming.

Destructive Feedback:  One of the most disturbing possibilities associated with fossil fuel produced climate change is that of destructive feedback loops.  The world's oceans-as well as tropical forests-are vast storage "sinks" for carbon dioxide: if it were not for oceans the amount of CO2 in the atmosphere would be much greater than it is today. However, what would happen if, because of human-made climate change, the Earth's oceans began to release their stored carbon dioxide into the atmosphere?  Just this possibility has recently come under study, and is the basis for Hawking's speculations on a Venus-like future Earth.

Although there are several ways in which global warming could weaken the ability of oceans to hold carbon dioxide; a major one is through the destruction of phytoplankton organisms ( the foundation of the entire ocean food chain ) which are one of the oceans' primary CO2 absorbers.  Once this happens, much more carbon dioxide will enter the atmosphere, greatly speeding global warming--which will in turn destroy more phytoplankton.  Which will further increase warming.

This and other chaos-like feedback loops could shift climate change from a gradual process to a sudden qualitative plunge to planetary disaster.  This prospect is not impossible.

What Can Be Done?  As scientists, activists, private groups and governments have become convinced of the reality of global climate change, at least some tentative steps have been taken to deal with the problem in a coordinated fashion,  In 1992, an international Climate Change Convention was established with the aim of getting developed nations to take measures to stabilize greenhouse ( fossil fuel ) gas emissions at 1990 levels by 2000, and for all countries to limit emissions, gather information and cooperate in research and technology.  In 1997, the Kyoto Protocol was adopted.  Kyoto called for legally binding commitments to reduce greenhouse gases by at least 5% by the period 2008-2012.  The United States Congress, however, has not as yet agreed to ratify the Kyoto Protocol.

Unfortunately, most of the 'solutions' envisioned by the Climate Change Convention, and even by Kyoto, are essentially technological and do not address the fact that modern global climate change is at bottom a social process.  Massive amounts of fossil fuel gases have been placed in the atmosphere over the past 150 years not so much because of technology but because of the specific way human beings have produced and exchanged goods during this period.  Perhaps the most striking example of this is the private automobile.  Automobile emissions are one of the primary contributors to atmospheric CO2 increase--and yet from a technological point of view the automobile is almost entirely unnecessary.  Automobile use has been promoted for the profit of oil companies and auto manufactures, for military mobility; and accepted by a public fed immature notions of "personal freedom and independence".  And in fact the entirety of modern global consumer society can be seen in the same light.

The point here is that the rational solution to the automobile problem is not more efficient engines with lower emissions but elimination of the product all together.  In other words, and extending the argument, the real solution to the climate change threat is not primarily technological reform; it is a matter of political will and social vision.  Whether or not these can be brought into play in time to prevent radical change in the Earth's atmosphere, oceans, and biosphere-and assure the survival of our present society is an open question.  Never-the-less, and whatever ultimately happens, vision and political will are the two things that will have to be mobilized eventually if human society is to have an enlightened, democratic future.

At some point, climate change will bring the Fossil Fuel Age to an end.  The question is, what will follow it.  In considering this question, one disturbing fact should be kept in mind: much has already happened that will not be undone for a long, long time. Referencing a 2001 Intergovernmental Panel on Climate Change ( IPCC ) report, J. T. Hardy says, "Even if all emissions of greenhouse gases decline linearly to zero from 2100 to 2200, the Earth's climate will probably remain altered for centuries to come.  These changes will have serious effects on the Earth's ecosystems that support human civilization."(3)  In other words, when it comes to human caused climate change, it may be time to start thinking not only about prevention but how we are going to live in a future world we have already created.

(1)  Nando Times, 9/30/2000.  Archived at http://eces.org/archive/ec/globalwarming/runaway.shtml

(2)  Manabe, S. and R. J. Stouffer 1995. "Simulation of abrupt climate change induced by freshwater input to the North Atlantic", Nature 378, 165-167; Russell,G. L. and D. Rind, "Response to CO2 transient increase in the GISS couple model: Regional coolings in a warming climate", J. Climate 12, 531-539

(3)  John T. Hardy, Climate Change, John Wiley, 2003, p.72