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New Zealand Engineering 1999 June Letters Can't see
the forest for the trees Can't
see the forest the trees It is not the process of photosynthesis which constitutes the carbon sink, because if plant respiration and photosynthesis are in balance then there is no net sink. The sink occurs because a forested landscape contains more carbon in the vegetation than one in pasture or annual crops. The act of converting one type of land cover to another changes the carbon density (tonnes carbon per hectare) of the landscape. In the case of replacement of pasture by a forest of radiata pine grown on a 28-year cycle, this represents a one-off net movement of carbon from the atmosphere to the earths surface of about 100 tonnes carbon per hectare. I use the word "forest" advisedly, a forest being a collection of component "stands", which are typically even-aged. A forest with an even balance of age classes would be in a steady-state situation, with no change in carbon density. It would be a carbon reservoir, but not a sink. In order to make this concept more intuitive, let us consider deforestation. This is the permanent removal of forest cover and replacement with a non-forested cover (not to be confused, as did Peter King in his article, with harvesting which is a temporary phase in a cycle, and usually affects only some stands in a forest in any one year). Imagine a swathe of the Amazon jungle torched, and you can picture the carbon being transferred from the woody material (where it comprises half the oven-dry weight) to the atmosphere. Afforestation, or the establishment of a forest on a non-forested area, is merely the reverse process. Given that New Zealand has anything up to five
million hectares of land in pasture that could be considered unsustainable for reasons of
economics, erosion and weed ingress, and given that the carbon density of this land could
be increased by at least 100 tonnes carbon per hectare, this represents a potential carbon
sink of 500 million tonnes of carbon or 1833 million tonnes carbon dioxide. Valued at even
a lowly $10 a tonne of CO Piers Maclaren Rangiora Truth, the profession and climate change D A Wilsons splendid letter (NZE April 1999) must set engineers wondering how theyve got into the state of bondage to accountants, lawyers and bureaucrats - and to politicians. Imagine engineers of the past, such as Bull Hansen, in these circumstances, meekly accepting the control by these non-technical people of decisions for which professional engineers traditionally had the authority and the responsibility. Inevitably, the changed circumstances have led to a sad loss of engineers professional standing. The engineers involved today are more likely to be consultants whose advice may or may not have any effect on the non-technical decision makers. The engineer has to accept these conditions, otherwise he wont be appointed as consultant next time. Eventually, the downward slide will correct itself naturally as the mistakes of the new engineering "order" become apparent - the Mercury fiasco (an American report, June 1998, stated - "The government has mandated an inquiry, but specified that privatisation is not to be considered as a possible cause"!); the demolition of the corps of engineers, the toast of the engineering world, which produced the lowest-priced power in the world; the electricity "reforms" which certainly cannot live up to the politicians ludicrous claims for lower-priced power; Cave Creek, which brought about a Ministers resignation over design errors with a viewing platform; the perceived need to drain the surroundings to the Clyde Dam, (deemed unnecessary by the designers, and reputed to have cost an extra one billion dollars). The official organ of the profession (New Zealand Engineering) illustrates how abject engineers embrace the principles of their new lords and masters to whom they seem so eager to be subservient - largely unconcerned with engineering issues, its pages seem rather devoted to politically-correct statements for the benefit of their accountancy and legal associates and for bureaucrats in general. The April issue of NZE reflects, more than usual, the sad trend. Theres an article on ownership of New Zealand rivers, certainly of general interest, but without specific concern for engineers, and presenting only one side of this thorny issue - a partisan opinion by one proclaimed as independent. But the most worrying feature of this April issue is the major article "Profiting from Climate Change" which exemplifies the policy of the official engineering body in ignoring the developing greenhouse Truth, seeing more advantage in supporting the vested interests of their non-technical associates in the western worlds dishonest, fast-growing industry. Here they are promoting the claim that New
Zealand, through some nebulous scheme for the trading of emissions, can profit from the
as-yet non-existent agreement to control the level of the "pollutant" CO The technical world - at least those people who
are not on the greenhouse gravy train - are quickly coming to the conclusion that changing
CO Given these facts, engineers must seek the Truth, taking time to comprehend the factors that destroy the greenhouse fallacy. Above all, the acceptance of the untrue cannot be justified on the spurious claim that it could lead to some mythical profit. The lack of technical content in NZE led the writer, some six months ago, to subscribe to NZ Engineering News. Coincidentally, the April 99 issue of the latter published the greenhouse Truth in an article "Global Warming is not our Fault" - while, in line with NZEs avoidance of the Truth, its April issue presented this "Profiting from Climate Change". Comparison of the two articles explains why engineers should stick to their technical last, rather than embrace the dishonesty of the self-seeking lawyers, politicians, accountants and bureaucrats, who are ruining the proud standing of their professional body. Peter A Toynbee |
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