In this issue we again visit the ever-expanding universe of climate change. Recently, even the Americans and Australians have shown some governmental interest in the subject and our own political parties are revamping their policies. I have to agree with the Greens that our initiatives have hitherto been feeble. A target of 3.4 per cent of biofuels by 2012 (up from an initial suggestion of 2.25 per cent) is hardly going to save the world! Surely 15–20 per cent should have been achievable in five years.
However, biofuels are not my focus in this missive. For some time I have been troubled by the notion of buying carbon credits to offset CO2 production, and then claiming that the purchasing enterprise is carbon neutral. It seems a bit too slick and painless. The carbon credits may be in the form of wind-generated energy or subsidies for cleaner-burning cookers in some third world countries, but often they are tree plantings—somewhere. The idea is that the trees are going to grow and suck carbon out of the air to form their wood and leaves and the enterprise will buy a carbon sink equal to their production.
Can we be sure that the trees are planted and that they grow as planned? If they grow more slowly than anticipated, they will not be removing as much carbon as the enterprise is producing. And as the trees start to approach maturity, their growth slows so they become less effective carbon sinks. Then, for the scheme to be meaningful, those trees must never be cut down. Most trees—like all other living things—have finite lives: eventually, they die, releasing their sequestered carbon as they decompose. Generally the faster a tree grows and the better a carbon sink it is in the short term, the shorter its life. Slow growing trees like most NZ natives will be sinks for a much longer time than pines, but their uptake will be slow. There don’t seem to be any free lunches here.
The other question that should be asked is whether the offset trees would have grown without the carbon credit payment incentives. The answer could well be, “not now”, but that really isn’t good enough. If woody vegetation would ever have regrown on the site naturally, it seems to me that the carbon credit is questionable. And what is the end of the practice of planting forests that cannot be cut down? Senescent trees covering most parts of the earth that can sustain tree growth? That seems a nonsense. Of course, given the level of corruption in the world, it is entirely likely that offset forests in third world countries will never be planted or else will be quickly harvested for firewood and the like. The potential for abuse is vast and not only in the less developed world.
We come back to biofuels here. One of the objections to them is that too much land will be consumed in their production. Well, the carbon offset credits are going to take just as much space, with the major difference that the biofuel land can be grown, harvested, replanted, harvested again etc. The carbon offset land is going to be planted and left and more will have to be locked up each year as fuel consumption rises and tree growth slows.
English academic, writer and activist George Monbiot has compared carbon offsets to the medieval Catholic practice of selling indulgences (http://www. monbiot.com/archives/2006/10/19/selling-indulgences/). Under this fine system, intending sinners could pay the priest money in exchange for indemnity from the consequences of their future misdemeanors. Fancy some adultery? Well, it was a lot more expensive than petty theft but the priest would still absolve you in advance! Your heavenly eternity would remain intact as long as you could afford to pay for your sins in the currency of the day. I somehow doubt that the scheme cut much ice with God. Will our present clever schemes prove a substitute for weaning ourselves off fossil fuels? Levels of atmospheric carbon dioxide continue to rise despite Kyoto.