Friday, April 20, 2007

Carbon-Trading, the Ozone Layer and Frying Fish.

While the developed nations have all but banned manufacture of CFC's (chlorofluorocarbons) and related compounds, in the interests of trying to preserve the ozone layer, they are paying billions to countries like India and China to produce them. The problem is a loophole in the Kyoto Protocol which allows industrialised nations to meet their own greenhouse gas emissions by paying for cheaper emission reducing projects in developing nations. The Clean Development Mechanism (CDM) means that for every tonne of carbon saved (or its equivalent, denoted CO2e), one "carbon credit" is earned. Nearly half of all CDM credits have been issued for destroying HFC-23 (trifluoromethane), which is 11,700 times more potent as a greenhouse gas than CO2, and is produced during the manufacture of HCFC-22 (chlorodifluoromethane), which is widely employed as a refrigerant. The situation is very opportune for China and India, since they hold most of the developing world's facilities for manufacturing refrigerants, and foreign investors are prepared to pay up to 15 Euro for each CO2e credit - a lot less than it would cost to reduce emissions in Europe or the US!

In a recent paper published in Nature, it was estimated by Michael Wara, who is both a lawyer and an authority on CDM, the total cost of destroying HFC-23 via carbon credits is 4.7 billion Euro, whereas the actual cost to do it is more like 100 million Euro. He points out that this isn't merely an expensive loophole, it also discourages more desirable CDM projects based around biomass or wind-power, and might engender an incentive for companies in the developing nations to expand production of refrigerants for the simple purpose of destroying by-products from HFC-23 production.

So, how is the "ozone hole" these days? You may recall that the whole business of ceasing to manufacture CFC's and indeed of destroying existing stockpiles was to do with the fact that these volatile compounds survive transport through the troposphere, to reach the stratosphere where the ozone is, and there they are photolysed in a series of chemical reactions that result in decomposition of the ozone layer. This is also sometimes called the ozone-shield, in emphasis that ozone absorbs harmful UV radiation (UV-A and UV-B), and helps to protect life on earth from its harmful effects, e.g. causing skin-cancer. A well-documented "hole" has appeared in the ozone layer, most dramatically over Antarctica and worryingly over Europe too.

Earth systems are complex, and it is probably misleading to consider any aspect in isolation from the highly interconnected whole. There is no better example of a holistic system at work than the Earth and its climate. (A philosophical overview of this has been espoused in the novel Jagged Environment, by Chris James). Indeed, it is now thought that marine and freshwater systems might be placed at risk by the increasing levels of UV now reaching the Earth' surface. Aquatic ecosystems constitute more than half the biomass of the planet and are hence an essential component of the biosphere. According to a report by the United Nations, marine organisms may be killed-off by the UV, especially in the polar regions above where the ozone layer is thinnest, and such a diminution in marine organisms, e.g. phytoplankton, may reduce the capacity of the oceans to soak-up CO2 from the atmosphere.

I have noted previously, "Carbon in the Sky" (6-1-07), that since 1950 the amount of CO2 emitted into the atmosphere from burning fossil-fuels appears to have exceeded the planet's ability to absorb it by an average of 40%, or around 2 ppm per year. That excess seems to be increasing, probably in consequence of steadily increasing levels of emissions but also destruction of the world's forests and the phytoplankton - "green lawns" - of the oceans. Phytoplankton is thought to absorb more than half the CO2 that is taken-up from the atmosphere by the plant kingdom altogether through photosynthesis, and hence is responsible for over 50% of the atmosphere's oxygen. The fear is, of course, that an increase in atmospheric CO2 might lead to more dramatic global warming.

It is interesting that although there appears to be no direct link between "global warming" and the "ozone layer", there are indirect connections. Here, through the interactive ozone-hole/UV/phytoplankton/CO2 system, and that while rising CO2 levels cause the troposphere to warm, they cause the stratosphere to cool, leading to more cloud formation upon the surfaces of which more ozone is decomposed, we have a perfect (deadly!) "feedback mechanism". The interconnected processes of the Earth "systems" indeed constitute an intricate and delicate mechanism, and we tamper with it at our peril.

Related Reading.

Jagged Environment, by Chris James. This is described as: "A discussion on the origins of life and the relative impact of humankind on the environment". Personally, I found it interesting from a philosophical point of view, whether I agree with the "science" or not! "

Chemistry World, April 2007, Vol. 4, No. 4, p.8/p.32.
D.P.Hader et al., Photochem. Photobiol. Sci., 2007, 6, p.267.
M.Wara, Nature, 2007, 445, p.595.