Friday, April 10, 2015

Climate change: The latest inventory

The annual inventory report [PDF] of our greenhouse gas emissions has been released. The headline data:

Gross emissions have declined slightly, continuing the trend of remaining fairly static, but somehow growth in net emissions has ceased entirely. There doesn't seem to be any reason for this - there's certainly been no policy change - but somehow the growth in deforestation we were seeing after National gutted the ETS magically stopped in 2013, despite plummeting carbon prices.

What there has been is a significant change to calculation methods which has seriously altered the entire forest removals time series so a 10 million ton increase in deforestation since 1990 has suddenly become 2 million (I guess MPI really got value for money there). All the data in this year's report has been recalculated using the new methods, so its all internally consistent - but the differences with what the inventory was telling us last year, and the year before, are striking. Which makes it pretty hard to plan policy if what seems to be a problem changes so dramatically from year to year. Should we target deforestation or the energy sector? Whichever we choose, the numbers will have changed before we can bring a paper to Cabinet. No wonder we have policy paralysis.