How much land do we really need to plant with trees?

Both the government and the Climate Change Commission have misrepresented how much land will be covered in forests in 2050 with current emissions policies.

In its final report, the Commission told the government the existing policies and the Emissions Trading Scheme at $50 will deliver net zero emissions in 2050.

That extraordinary finding put a significant dent in the case for the Commission’s plan which has us paying somewhere between $250 and more than $500 per tonne of emissions – not $50 – to achieve the same emissions goal.

The Commission needed a way to explain why we should not stick with existing policies, which its own modelling shows more affordable and as effective as their plan. Their primary argument is that existing policies plant too many exotic trees.

The Commission and ministers have made various statements to this effect. For example, back in June, James Shaw told Parliament’s Environment Committee this (at 44:07 and again at 44:22):

[T]he pathway to getting to net zero at the least cost… involve[s] converting virtually every farm in the country into pine forestry.

Shaw’s statement is not close to being correct.

In its final report, the Climate Change Commission says getting to net zero emissions with existing policies including the ETS at $50 will require an additional 1.24 million hectares of exotic forests to be planted by 2050.

That is only 11% of the 11.7 million hectares of New Zealand farms which are not already forested. So much for Shaw’s “virtually every farm” claim.

Perhaps Shaw meant some time after 2050? So at what date could the last New Zealand farm be forested if we extrapolate from the rate between now until 2050?

On conservative assumptions, the earliest date exotic forests will cover the last New Zealand farm will be in the year 2250. That is about the same year the USS Enterprise from Star Trek is scheduled to launch.

But that date is based on the most conservative assumptions possible: gross emissions never fall from their current levels; all trees are only planted on farmland; agriculture pays a carbon price near zero; and zero access to offshore emissions units.

More realistically, the last farm land will not be forested until sometime after the year 2500.

Except the last farm will never be covered in trees – ever. We have land markets which mean trees will become an uneconomic way to capture and store carbon emissions long before the last farm is covered in pines.

In any case, the afforestation problem does not have to be solved today and certainly not by the central government. Local councils should be asked to do the job of capping afforestation in their areas, which has the advantage of being democratic and based on the circumstances which confront them in the future.

Remember there is a constituency for trees as well as against. Many landowners like trees because they are profitable. Funny how a carbon price helps do that.

The Commission’s main argument that existing policies will plant too many trees is almost equally applicable to its own plan.

The Commission’s modelling shows its plan will plant a further 4.4% of New Zealand’s total land area in forests. That compares to an extra 5.1% for current policies.

The Commission’s plan plants more native trees and fewer exotics, but this change in composition is hardly earthshaking. With current policies, exotics will make up 24% of all trees in 2050; under the Commission’s plan, 19%. Would anybody but industry insiders notice the difference?

See if you can spot the difference in outcomes between existing policies, which deliver net zero emissions in 2050 with an ETS price of $50, and the Commission’s plan, which has us paying between $250 and more than $500 per tonne of carbon:

By contrast to these minor changes in land use, households and businesses will not fail to notice the effects of the Commission’s plan on their cost of living. With carbon prices of between $250 and more than $500 per tonne, the Commission’s plan will profoundly affect the cost of everything, especially energy and travel. Its worst effects will almost certainly fall on low-income households.

As far as I can tell, the Commission has not considered the consequences of its ruinous plan for households and individuals living on low incomes. Its distributional analysis mainly considers effects across economic sectors of the economy – which is not really a distributional analysis at all. For all the talk about equity, it is not clear the Commission has checked what $500/tonne means for the price of bread, the cost of your daily commute, your power bill, or a flight to Auckland.

Another problem is that the Commission has presented existing policies as relying too much on trees and not enough on gross emissions reductions i.e. reductions at source.

But the Commission’s modelling shows existing policies do far more than just plant trees to lower emissions. Modelling for its draft report (it does not seem to have been repeated for the final report) showed that by 2075, 74% of the reduction in net emissions would come from lower gross emissions with existing policies including the ETS; only 26% from removals.

Is successful delivery of our emissions targets, but with a few more exotic trees and a somewhat more gradual transition in gross emissions, so bad as to justify paying between five to ten times more per tonne of carbon? Consider which option puts our emissions targets at greater risk.

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