Friday, January 25, 2008

Climate change: the false goal of emissions intensity

Over on PASystem, Don Christie asks the obvious question in response to our dismal progress on reducing emissions: "what about emissions intensity?" Firstly, our emissions intensity has indeed improved over the years, as shown in the graph below:

(Source: emissions from National Inventory Report; GDP in constant 1995/96 dollars from

The problem is, firstly, that it has not improved by enough (that lack of policy again) - in order to generate today's GDP on 1990's emissions, it'd need to be over $2,000 / ton of CO2. But more importantly, intensity is a false goal. If we are to deal with the problem of climate change, we need to actually reduce emissions. If we are to maintain the same standard of living while doing so, we must significantly improve intensity. But that alone isn't enough, because it is perfectly possible to improve intensity while spewing even more carbon into the atmosphere. And that is exactly what has happened in New Zealand over the last decade.

Basically, intensity targets give the illusion of progress while doing nothing at all to address the real problem. And that is why I prefer to focus on gross and net emissions.

But there's also another type of carbon intensity we can measure - emissions per capita. And on that front, New Zealand hasn't been doing very well at all:

(Source: emissions from National Inventory Report; population figures from

Despite all our progress in making more money per ton of carbon emitted, we now emit almost a ton more per person than we did in 1991. Again, this can be an illusory statistic - per capita emissions can reduce while emissions rise if the population is growing - but it captures the essential task better than GDP does. If we are to deal with the problem, we need to get per capita emissions heading steadily downwards. And in the long term, they need to reduce by well over 50%.

The good news is that now New Zealand has policy, which should prod the economy (and hence people's emissions) in the right direction. But it'll take a few years before it is all fully implemented, and there are serious questions as to whether it will be enough to produce the necessary reductions.