Posts Tagged ‘atmosphere’

Geo-engineering – To use or not to use

October 24, 2010

One of the most topical debates going on at present is on the subject of Geo-engineering.  Should or should it not be used to prevent global warming and if so which methods are most appropriate.

It is certainly true that we humans have historically justified our pollution of the earth on the grounds that “Oh it is only a little drop of ‘Chemical X’ that we are adding to the huge volume of the earth’s oceans/water bodies/atmosphere/soil etc.”  The idea being that the recipient medium is so huge that it really will not make any difference.  Now alas, we know for certain that this is not the case.  Whereas, what goes into the soil is usually broken down sooner or later by the soil’s bacterial cocktail, if it reaches a water body or the atmosphere, the story is very different.  For example:  PCBs (polychlorinated biphenols) turn up in unexpected places, having being concentrated by the oceans’ currents.  They then lodge in fish oils and the fats of marine mammals and the associated human communities.  Once in animal bodies, we do not even now know the full extent of their effects; but we do know that they seem to have a bad effect on the reproductive system.   The chemicals released to our atmosphere, are similarly dissipated and not only travel around the globe in the Trophosphere, but some also seem to affect the gaseous mix in the Stratosphere.

However, I am against Geo-engineering for the following reasons:

Firstly, because the suggested strategies are relatively easy to put in place, but virtually impossible to remove, should the situation swing too far in the other direction.  The need to be able to fully control anything that we do, is not so daft as it may seem.  Already the planet has proved to be unstable in its circa 4.6bn year history.  Geological records and the volcanologists tell us that we are due for a reversal of the magnetic poles; though it was thought that this was a process that would take thousands of years, the latest information suggests that it in the past it has occurred over a mere 4 years!  We know for certain that in the history of life on earth, parts of the planet have been a lot warmer, a lot wetter and a lot colder than they are now.  NB there are huge aquifers under parts of the Sahara and records of predators that could not have survived without large herds of herbivores that in turn could not have survived without grasses and shrubs.  So whatever we do our strategies must be adaptable; and I suggest that we should begin by moving to renewable energy supplies, stop use of fossil fuels unless we are prepared to reconvert the carbon dioxide and water to hydrocarbons, and do what we can to clean up the toxic chemicals that we have released into our oceans and prevent further releases.  The following are my comments on some of the Geo-engineering strategies that have been suggested.

Carbon capture and storage, actually means storage of carbon dioxide (CO2) produced by the process of combustion in our atmosphere.  Thus for every 44gms of CO2 stored we would be removing 32gms of oxygen (O2) from our atmosphere.  Mammals have fairly advanced and efficient lungs but cannot abstract anything like 100% of the O2 inhaled. Invertebrates and Fish etc. are far less efficient and the 20% O2 in our atmosphere is likely to be necessary to provide high enough levels of dissolved Oxygen in the water to support its life forms, especially the Zooplankton.  Storing the carbon on its own would be OK, but better still: why not convert the CO2 back to hydrocarbons or electricity.  A number of research projects are already showing a lot of promise – from solar furnaces to electrochemical cells.

Seeding the ocean with Iron/fertilizers is equally daft.  We already know a lot about the effects of algal blooms due to ‘accidental’ release of fertilizers into the seas and freshwaters of the planet. The increased surface algae die and sink, meanwhile the decomposers get to work and in living remove large amounts of Oxygen from the water; with the result that it becomes too deoxygenated for the survival of the waters fish and their larval stages.

Global warming will, under the normal laws of physics, give rise to higher evaporation rates from the water’s surface.  So there should be no need for the expensive practice of spraying seawater up into the clouds!

The placing of trillions of tiny solar reflectors in space to prevent a percentage of the sunlight from reaching Earth, seems equally fraught.  How are these to be controlled, removed, repositioned etc. We have a complex series of temperature inversions that are not well understood in the atmosphere.  Moving up through the Trophosphere the air cools to well below freezing point at approx 16km up at the equator and 7km at the poles; it then warms up in the Stratosphere until it reaches 0oC at approx the boundary with the Mesosphere at an approximate height of 50km.  However, by the middle of the Mesosphere it has cooled to -90oC, finally warming up to a deep blanket of between 570o – 1570o (night & day and summer & winter temperatures)as it moves up through the Ionosphere, over the next 800 or so kilometres.  I strongly feel that we should not tinker with things that we do not fully understand; just because it seems to be OK if we consider one set of criteria, does not mean that it will be OK if we considered the full as yet unknown set.

Finally, there is the suggestion to release sulphate particles into the stratosphere (approx. 16 – 45km high).  Again, how is it proposed that we control the actual position of these, either around the globe or in terms of their placing in the stratosphere?  What is the chemical effect of placing sulphate particles in our upper atmosphere?  It has been suggested that doing this would be no more damaging than the effect of a large volcanic eruption on the surface of the planet, despite the fact that In general the effects of volcanic eruptions are not welcomed on the surface.  Plus if we are intent on blocking the sunlight, then we also reduce the possibility of power from photovoltaic panels.  This could push the planet towards nuclear power i.e. the use of a very finite resource and one with a very high invisible medical and genetic risk at every stage of its use from mining through to waste storage.  There are simply too many questions that remain unanswered, yet they need to be fully considered by experts in all the branches of scientific knowledge and research, before there is any move to carry out the procedure, or even to trial it.

Please let a wide understanding, of all the mechanisms and needs involved, over-rule uncontrollable geo-engineering and further waste of resources with unknown consequences.  Please let know how you feel about this topic.  A knee-jerk reaction now could, by chance, have an excellent result, but is more likely to cause a catastrophic reaction either for us or future generations.