James Lovelock FRS put forwards the hypothesis that the whole planet, including its molten core and all living organisms, is a single living climate regulating system that keeps global temperatures within such limits that life can flourish. This is accomplished by negative feedback mechanisms, which enable the planet to withstand disturbances such as ice ages. Lovelock calls this living planet Gaia, named after the Greek earth goddess Gaia. But mankind has stressed Gaia so much that soon it will probably not be able to maintain the present temperature limits; rather it will fairly suddenly switch to a much hotter regulatory system where the majority of mankind will be killed.
Feed back is a process in which changing one quantity changes a second quantity, and the change in the second quantity in turn changes the first.
Positive feedback increases the change in the first quantity while negative feedback reduces it. Feedback is important in the study of global warming because it may amplify or diminish the effect of a particular process.
Lovelock gives an explanation:
“When a car we are driving deviates from our intended path we alter the direction of the front wheels sufficiently to cancel the deviation. The error we have sensed is amplified by the power steering and applied to oppose the error. This is negative feedback. If by accident the steering mechanism was faulty and it increased, not opposed, the car’s deviation, the error would be amplified and this would be an example of positive feedback” (reference two below).
Lovelock finds evidence that various positive feedback mechanisms have come into play in recent times. An example here of positive feedback concerns ice and water in the Greenland area. To provide a perspective, Lovelock notes that the floating ice of theArctic covers an area equal to the area of the United States.
In the Greenland area there are two principal surfaces – exposed ground and ocean waters on the one hand that appear very dark from space, and snow and ice on the other. Snow and ice reflect sunlight, and so reflect heat back into space. But exposed ground and ocean waters absorb heat. So bare ground, or water adjacent to ice and snow, melts the latter, reducing the total area of snow and ice and increasing dark areas, and this process continues.
Lovelock also writes that the immediate cause of global warming is the increased production of carbon dioxide through fossil fuel combustion. But this increased production is occurring at the same time that forests which play such a major role in regulating climate, are being destroyed, and other ecosystems vital to Gaia are being debilitated. And underlying all these changes is the growth of the world human population – “the root of our problems with the environment comes from a lack of constraint on the growth of population“(our bold text; reference two page 140).
Lovelock in his latest (2009) book A final warning. The vanishing face of Gaia (reference three) writes that this fairly sudden change to a hotter state is now almost certain to take place. Even the most stringent conditions proposed to deal with climate change, let alone the feeble ones so far agreed to by most nations are inadequate to stop it.
Lest you might think Lovelock is a crank, we add this. The foreword to the book is written by Sir Martin Rees, Master of Trinity College and Professor of Cosmology and Astrophysics at CambridgeUniversity and he was at the time of writing President of the Royal Society.
Rees writes: “He is both a fine scientist and an eloquent advocate of action”. And “It is no exaggeration to say that our civilisation’s long-term future depends on whether the ‘call to arms’ in this riveting book is widely heeded”.
References.
- The ages of Gaia. A biography of our living earth. Oxford University Press, 1988.
- The revenge of Gaia. Penguin Books 2006.
- A final warning. The vanishing face of Gaia. Allen Lane 2009, Penguin Books 2010.