The PCE has a point on trees

Radio NZ report:

Few parts of the government’s plan emerged unscathed from the submission by Simon Upton, a former National Cabinet minister turned parliamentary commissioner for the environment.

He said relying on carbon pricing to drive down pollution in areas such as transport was “not coherent”.

He said the government was taking a “massive gamble” by relying on planting pine trees to offset carbon emissions instead of actually cutting emissions.

The PCE is correct that planting pine trees to offset carbon emissions is shortsighted.

The reason is that pine trees are usually harvested after 30 years. They can live longer but if pine trees are used as an offset against , that land has to be locked up for forestry for ever.

The reason is carbon emissions are very long lasting. They estimate that after 1,000 years a third to half of the CO2 stays in the atmosphere. So if one wants to keep using trees to offset CO2, then you’ll have to keep planting more and more and more, and keep them all there for 1,000 years or so (and replace the ones that die).

But this is not to say planting trees can’t play a useful role in reducing overall greenhouse gas emissions. Rather than allowing them to be a credit against CO2, we could allow them to be a credit against CH4 (methane).

You see methane does leave the atmosphere much more quickly. It is estimate to remain for just 12 years. Now using tree planting to offset methane makes more sense. The trees will last longer than the methane.

So a brave government would look at having two different ETSs. One for CO2 and one for Methane. And tree planting credits would only be available in the methane ETS. This would stop huge amounts of countryside being converted permanently to forestry. It would also allow farmers to plant to offer their own emissions.