I have just read
James Lovelock's book 'The Vanishing Face of Gaia, A Final Warning'. It is well worth reading. He makes a few simple but compelling arguments which I will summarise here:
The weather is part of a complex system that is inherently very difficult to predict accurately with any confidence. Scientists and in particular the
IPCC have become overly reliant on models and do not place enough emphasis on traditional scientific method based on observation and measurement. The measurements now suggest that sea levels are rising 1.6 times faster than the models predict and that the climate is heating 1.3 times faster than the models predict (
Science, May 2007) . He makes the point that nobody knows what will happen but that the
probability of extreme climate change happening much faster than the IPCC predict (ie in the next decade or two) has gone up significantly. Climate policy is therefore wholly inadequate and misguided based as it is on gradual predictable warming and a reassuringly gradual response (ie to reduce emissions by 60% by 2050 to avoid dangerous climate change).
He points out that there are powerful positive feedback forces at work some of which are not given sufficient (or any) weight in the models. These forces are capable of causing very rapid climate change because of the exponential nature of a positive feedback loop. The processes he mentions are:
I) Every summer larger areas of polar ice melt than the year before (
IPCC Nov 2007). Ice and snow reflect 60% more sunlight back into space than the darker water which absorbs more heat (because it has a lower
albedo). Thus as the ice caps shrink the same amount of sunlight heats the planet significantly more.
II) The less ice there is to melt the more the same amount of heat from the sun will warm the planet, because it takes 81 times more heat to melt ice than to raise the temperature of liquid water by one degree. This is because of what is known in physics as
latent heat. The heat energy that is not used to melt ice every summer will therefore heat the planet by much more as the buffer of ice diminishes.
III) In addition to their well known function of absorbing carbon dioxide, forests are important regulators of temperature. Trees draw water from beneath the soil and release it through their leaves in a process called evapotranspiration. It takes nearly 600 calories to evaporate one gram of water and this allows trees to maintain their leaf temperature at the optimal level for photosynthesis. In warm sunlight forests act as giant cooling systems affecting both local and global temperature. As forests recede so do these benefits recede, further boosting global warming.
IV) As the sea warms the amount of algae diminishes and there are now large barren areas of the ocean which are growing (
Jeffrey Polovina, Geophysical Research Letters 2008) Algae absorb carbon dioxide, so this further boosts the amount of greenhouse gases in the atmosphere. In addition as the seas die off they become darker and absorb more heat from the sun because the albedo of dark water is lower than that of algae-rich water.
(One effect he does not mention is that as the area of arctic tundra that melts each year increases it releases methane since much of the area is frozen peat bog. This has a huge impact since the greenhouse effect of methane is some twenty times that of CO2 and the areas affected are vast; in the many thousands of square kilometres
Nature July 2006)
All of these powerful mechanisms are part of a global positive feedback loop: as the earth heats, these effects promote further heating which in turn produce more of these effects and so on.
Lovelock says "I find it extraordinary that, given the depth of our ignorance, scientists are willing to put their names to predictions of climates up to fifty years from now and let them become the basis of policy. Surely they are not predictions, just speculations to assuage the fear of the dark clouds that loom on the climate horizon".
My conclusion is that it is probable that global warming will happen much faster than current projections and if that is what indeed happens then certain consequences will inevitably follow. Lovelock then says we should be preparing for those consequences now. I think he is right and that public policy should be an exercise in risk management; if something nasty is more likely to happen then it is responsible to take precautions in case it does happen.
So what are the likely consequences of faster and greater global warming ? Media coverage concentrates on higher sea levels and extreme weather events. These are clearly undesirable and dangerous outcomes but far more dangerous would be the catastrophic impact on agriculture.
If warming continues huge areas of agricultural land will become dust bowls, crops will fail and millions will starve. This is the main challenge of global warming. The processes that are in place are unlikely to be reversed by the timid efforts at carbon emission reduction that are being undertaken. Even if these efforts were accelerated Lovelock credibly argues that we are too late and should be directing our efforts towards preparing for the consequences rather than trying to assuage our consciences by switching off lights or buying carbon offsets (which he likens to papal indulgences).
Read the book. Move away from the tropics. Move away from the sea. Learn how to grow your own food, buy land, prepare to defend it. Convince your government to prepare for the likely consequences. These are the measures we should be taking.
