Global Warming

 

If the Pope is about to utter on global warming – why shouldn’t I?

 

The recent actions, or intended actions, by the G7 are an encouraging sign that the government of the world is beginning to take the problem of global warming and rising CO₂ levels seriously.  The emphasis on developing nuclear energy and other renewable sources of energy such as solar and tidal power are certainly to be welcomed.  On their own, they are however likely to do little more than to slow down the process and to delay the time when the effects of global warming become serious.  The development of effective energy production by nuclear fusion – “creating a mini sun on the earth” -may be an exception to this prognosis. 

 

However, there are two measures that could deal with the situation much more effectively.

 

The first is necessary, whatever other solutions are adopted. This is to arrest the growth of the human population or indeed to secure some degree of decline.  The projections of global population growth have decreased over the last twenty years, The main factor that seems to have been involved is the improvement of living standards and particularly of women’s education in the developing world and, not least, the provision of bathrooms, which make contraception much easier.  However, there are still populations which for religious reasons remain committed to the duty to breed as a primary human concern ; and in some cases such populations aim to outbreed their neighbours for political ends.  This is a problem that needs to dealt with by governments rather than by science. 

The other solution, however, which could deal effectively with global warming, though it would not prevent the exhaustion of other planetary resources that will come about unless the population is controlled,  is to genetically engineer major crop plants so as to increase their efficiency of photosynthesis.  This proposal was put forward by the late Lord Porter, a former President of the Royal Society and a very distinguished photochemist, in his 1995 Rajiv Gandhi lecture.  He pointed out that if the efficiency of photosynthesis could be improved from the present level of 1% to around 5% then this would allow all the food and energy needs of the planet to be met from the amount of agricultural land under cultivation at that time.  This is not an easy problem to solve.  The initial enzyme, Rubisco, is notoriously inefficient and early attempts to increase its efficiency were unsuccessful.  However, with the greatly increased knowledge of molecular biology and of the role of chaperones it does seem possible that this could be achieved if a major effort were put into it.  Although some laboratories are currently involved in this work, it really requires an effort on the scale of the Manhattan Project since this is an innovation which could literally save the planet.  There has been some scepticism of this approach on the grounds that evolution would have achieved an increased efficiency of photosynthesis if this were possible.  This argument is, however, fallacious.  When CO₂ levels are low, there is no evolutionary advantage in raising  the efficiency of photosynthesis.  This would simply lead to the plants running out of CO₂ and being unable to continue photosynthesis.  In other words, increased efficiency of photosynthesis is valuable only when CO₂ levels are high and if we succeed in bringing them right down again using genetically engineered crops then in due course the world’s agriculture will revert to the less efficient crops that we have at the moment.  It might be of interest, if it were possible, to investigate the photosynthesis by  plants in the carboniferous age when there were indeed very high CO₂ levels and the present fossil fuels were being deposited in the ground.  It is, however, so long ago that it may not be possible to recover the genetic information one wants.  Nevertheless, this should be a project that is given huge support and one of the reasons that it isn’t is undoubtedly the irrational, but widespread, opposition to plant molecular biology and to the modification of food plants by genetic techniques. 

 

This opposition is totally irrational and is held largely by people who do not realise that all plant breeding involves genetic modification and that as a technique it is totally morally neutral.  It is, of course, necessary to take precautions about what gene one introduces to make sure that the product is not toxic or allergenic, or that the mode of insertion into the genome does not produce undesirable side effects.  That is already the case with all novel foods however they are produced.  Indeed, a common method of producing genetic variation in food plants, - irradiating the seeds,- produces much more widespread genomic change and is potentially much more damaging and therefore does require very careful control.  However, no-one should doubt that the root and branch opposition to genetic modification of plants is hugely harmful and may one day be seen as one of the main causes why we have been so inefficient in dealing with global warming and its potentially devastating consequences. 

This is an issue on which scientists should speak out.