Wednesday, April 15, 2009

Climate change: the net position

The government has released its Net Position Report 2009: New Zealand’s projected balance of Kyoto Protocol units during the first commitment period, which shows a dramatic improvement in our situation. From a projected Kyoto deficit of 21.7 million tons, we're now looking at a surplus of 9.6 million tons. So how did this happen?

Two words: methodological changes. The entire change - all 30 million tons worth - is due to shifts in how we project and calculate agricultural and forestry emissions. Some of this - for example, better projections of animal numbers, predicting 400,000 fewer dairy cows in 2010 as a result of drought and lower dairy prices - is good, and adds significantly to the accuracy of the projections. But some of it is very dodgy indeed. Dodgiest of all is MAF's decision to halve a number called Fracgasm, to do with the amount of animal excrement that turns into nitrous oxide (a powerful greenhouse gas). This "eliminates" 3.8 million tons of emissions - but the change has not been approved by the IPCC, and my sources inform me that the international reviewers might have some problems with NZ simultaneously claiming lower numbers for leaching, denitrification and volatilisation, which taken together means the nitrogen in that waste goes... nowhere. Also on the dodgy pile is the claim for 0.3 million tons due to the use of a nitrification inhibitor, which is similarly not IPCC approved (though this is small potatoes compared to the previous change).

There have also been big changes in how we calculate forest sinks and deforestation. They're now assuming a much higher rate of carbon absorption from post-1990 forests, based on the assumption that their owners never thin them or trim their trees. They assume that a large part of expected deforestation is immature forest which releases less carbon. And they're claiming that the rate of ineligible planting is lower than previously expected (again, that will need to be recognised by the IPCC).

Meanwhile, projected energy, industrial and transport-sector emissions are largely unchanged - because you can't twiddle the maths on those.

There are real changes: those 400,000 fewer cows make a massive change to our emissions, and the ETS really does seem to have significantly reduced deforestation. But the overall picture is of mathematical manipulation and juking the stats. But while they can do this for an (internal, NZ-only) net position report, they are going to have a much harder time doing it for our external, internationally peer-reviewed annual inventory reports. Those reports have a two-year lag-time, so we'll get our first real look at whether National's projections are worth the paper they're written on in early 2011 - just in time for the next election.