Now if this pans out, the New Zealand government should consider releasing the technology for everybody in the world to use, as New Zealand's substantive contribution to the fight against greenhouse gasses.
If high-end methane reductions maintain, New Zealand on net very likely will have done far more good in reducing agricultural methane than it could have done with a $30/tonne carbon charge.
If everyone in the world were doing carbon trading or carbon taxes, we'd want to as well. But, realistically, if New Zealand were to disappear into outer space tomorrow, it's pretty unclear that the entire abolition of New Zealand's net greenhouse gas emissions would do much on aggregate warming outcomes. Maybe we'd delay the onset of any particular level of GHG accumulation by a half day over a century. In that case, New Zealand could perhaps do better by picking high variance plays despite their lower expected mean. Pour money into biotech research for low GHG pastoral systems and give the resulting technology away to anybody who wants to use it. Lower expected returns, but if it pans out, it could reduce GHG emissions by a heck of a lot more than NZ could achieve on its own via domestic incremental reductions in carbon or methane emissions.Some lotto investments are worthwhile.