Dear Roy, Thank you for your detailed response.
You raise some issues about the risks of geo-engineering - but what is the risk of not geo-engineering? I believe that if we do not use geo-engineering, at least to save the Arctic sea ice, we will condemn the world to (a) massive methane release from permafrost, leading to many degrees of global warming (b) Greenland ice sheet disintegration, leading to many metres of sea level rise. It is difficult to imagine how civilisation could survive such a double whammy. Thus, when you consider this risk of not geoengineering, any risks associated with the two SRM geoengineering techniques I recommend (essentially mimicking of natural processes - volcanic discharge into stratosphere and sea spray), pall into insignificance. Note that the conventional wisdom is that we can prevent global warming if we make sufficient emissions cuts (e.g. by more efficient use of energy and by use of renewables) over the next few decades. This is a lie. It is a lie for the following reasons: 1. the lifetime of CO2 is effectively thousands of years, so global warming from anthropogenic legacy CO2 is bound to continue into the next century unabated; 2. even if CO2 levels could be reduced to 350 ppm over a few decades (Prof Hansen's target), the Arctic is warming so rapidly that the methane release and Greenland ice sheet disintegration will happen before the reduction in greenhouse gas forcing could have any significant effect; 3. one actually needs a negative forcing to cool the Arctic - reduction of CO2 levels, even to a pre-industrial level, will reduce the positive forcing, but not make it go negative. 4. the net positive forcing from greenhouse gases is of the order of 1.6 Watts/m2, whereas we need to counter a much higher forcing, of the order of 30 Watts/m2, caused by the Arctic sea ice albedo effect (as ice replaced by sea, solar energy is mostly absorbed instead of being mostly reflected back into space). There is no alternative to geoengineering for saving the Arctic sea ice. BTW, neither geoengineering technique is particularly expensive (each would cost less than $1 billion per year), and neither uses much energy for deployment compared to solar energy reflected. Nor is there any commercial interest in providing the technology, because there is nothing to sell. Cheers, John ----- Original Message ----- From: Roy Tindle To: John Nissen Sent: Wednesday, January 21, 2009 6:47 PM Subject: Re: [localsustuk] Re: [geo] What is geo-engineering? Interesting quote from Wikipedia but what a pity that the article wasn't quoted in full. But that wouldn't have supported this dead-end case, would it? Wikipedia, quite correctly, observes the many pitfalls, dangers and objections to these techniques, much promoted by engineering companies who could profit from such dangerous interventions - and by those with only a passing understanding of the physics - and chemistry - involved. Perhaps the most significant point to observe is that any major attempt at a worldwide Geo -engineering project would require world wide political agreement. Wikipedia refers to the possibility of side effects such as droughts etc, any of which could easily be regarded as deliberate and which could spark a global conflict. Imagine, for example, a US led initiative to spray sulphur dioxide aerosols into the upper atmosphere and that these fell as crop destroying acid rain on Russia and caused an extreme drought in Iran. Our understanding of atmospheric physics has grown considerably but it has a long way to go. There are still far too many interactions that we can not fully understand and the complexity of these interactions is so great that we are unable to compute them with accuracy. Hence we have good climate modelling but poor weather forecasting. So we solve one man made disaster by setting up another? Consider, also, the energy implications of some of the suggested processes. Whilst fossil fuels still provide most of our energy it doesn't seem such a good idea to embark on the world's largest ever engineering venture and so to put even more CO2 into the atmosphere in the hope that it may cure the problem. Then there's another little problem: we're at the beginning of a world-wide recession. The cost of many of the suggested interventions, at least those with some hope of working, is massive so engage in geo-engineering and imagine what will happen to renewables. I wonder how long it would take most politicians and corporations to drop any help for renewable energy development because of the cost of the intervention and because "a solution had been found". The real urgency is to begin to stop energy waste, to increase energy efficiency and to rapidly improve and deploy mature renewable generation technology. One of the worse aspects of the free market model is that academia has moved even further from cooperation and into competition, thus, instead of seeing any sensible coordination of research and development we tend towards a scramble for new ideas to attract new money. There are many economists who have no understanding of the natural sciences and many scientists who have as little understanding of economics. Unfortunately there seems to be an equal number of people seeking change who have little understanding of either. Fortunately our economic circumstances and the absence of any real degree of international political cooperation on climate change will almost certainly prevent such rash and dangerous action. 2009/1/21 John Nissen <[email protected]> > > > > > From Wikipedia: > > 'Geoengineering is the deliberate modification of Earth's environment on a large scale "to suit human needs and promote habitability".' > > There are two main classes of geo-engineering: one dealing with radiation input to the Earth from the sun; the other dealing with radiation output, trapped by greenhouse gases. The former class is sometimes called Solar Radiation Management, SRM, and involves reflecting the sun's radiation back into space. The latter class generally involves techniques to lower the level of greenhouse gases in the atmosphere. > > It is worth noting that one of the almost certain consequences of global warming is the Arctic sea ice retreat, see: > http://en.wikipedia.org/wiki/Arctic_shrinkage > This could be a tipping point for the whole Earth climate system, as further warming of the Arctic could lead to massive methane release from permafrost - sufficient methane to cause runaway global warming. > -- Roy Tindle Creekside Forum/ London Thames Gateway Forum Telephone 020 8141 0271 Mobile: 079 8884 7003 [email protected] --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "geoengineering" group. 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