With a population of 5 million, New Zealand has about 10 million cattle and 26 million sheep. About half of New Zealand’s greenhouse gas emissions come from agriculture.

Farmers will start paying for methane emissions from 2025, according to a draft plan released Wednesday. The rates for short (methane) and long (nitric oxide) gases will be different, but emissions will be measured in the same way.

The proposal includes tax incentives for farmers to reduce emissions of feed additives. To compensate for emissions, forests can be grown on farms. The tax on emissions will be earmarked – revenues will be invested in research, development and advisory services for farmers. The proposal would be the largest change to taxation of agriculture in New Zealand since the removal of subsidies in the 1980s.