The belch threatening the planet

There is no silver bullet which will blast away agriculture’s troublesome greenhouse gases. But that doesn’t mean the Government should do nothing. That is the rather cryptic conclusion of the report this week by the Parliamentary Commissioner for the Environment. Jan Wright certainly shows the limitations of the various means by which farming might minimise emissions. Her warning that change needs to start now is well-founded, but her policy recommendations are sparse.

She is right that farming can’t stay still in the hope that something will turn up. Agriculture emissions, the methane belched out by sheep and cattle and the nitrous oxide that comes from animal urine, account for nearly half of New Zealand’s greenhouse gas emissions. That makes this country unusual in global terms, and it presents a specific set of problems.

The best hope of a technological fix lies with an animal vaccine that would slash methane emissions. If the Government is pinning its hopes on this, however, Wright’s report is not encouraging. A usable vaccine, she warns, might never eventuate. Changes to the way animals are bred, or what they are fed, or how they are managed on the farm can help. But here too the prospects are limited.

The most promising route for agriculture is to plant more trees and to allow native bush to regenerate. Here Wright’s report marshals some very telling statistics. A million hectares of marginal land, if left to regenerate into native forest, could offset about 17 per cent of agricultural greenhouse gas emissions.

This is certainly an avenue worth pursuing, and Wright enthusiastically advocates it. There is also scope to plant pines and other trees on farmland. Treeplanting requires no technological breakthrough and can be done now.

There are, of course, problems. Much will depend on how forestry rules are negotiated in the wake of the profoundly important Paris agreement on climate change. Ngai Tahu argues that current rules often prevent afforestation using native species from earning carbon credits.

Rules need to be framed to encourage tree-planting; the Government claims it is already doing so through various incentive schemes. It remains to be seen whether the massive reafforestation programme envisaged by Wright will come about.

Some deeper issues remain. Wright has previously argued for including agriculture in the Emissions Trading Scheme, and this remains a necessary step. The Government refuses to take it till there are economically viable technologies available to reduce emissions and our trading partners make more progress on reducing emissions generally.

That, however, would be to wait too long. Abrupt transitions are undesirable, as Wright says, but if we don’t make a start then the transition in agriculture will have to be abrupt. Bringing agriculture into the ETS could be combined with transitional measures to recognise farming’s particular problems. But a start must be made.

There's no silver bullet for greenhouse gases from agriculture, but something must be done.