What can farmers do about climate change?
It doesn't matter what your opinion is on climate change, it is happening.
The challenge is what we can all do to slow it down.
For farmers this is a particularly complex challenge because any mitigation that decreases their production of food is bad for their livelihood and for everyone.
Farming is not a business that has had its time and can be closed down and replaced by something else. We all need food. We all like good quality food and none of us like to pay too much for it.
So farmers need mitigations that enable them to produce enough food for us all, while helping to save the planet from the impacts of climate change. But do these mitigations exist yet?
In my view, the short answer is yes for carbon dioxide but no for methane. For a time the other major greenhouse gas, nitrous oxide, could be mitigated by applying dicyandiamide (DCD) but the use of DCD products had to be withdrawn when they turned up in milk. DCD in milk highlights the complexity of finding safe solutions for decreasing the greenhouse gases produced by farming.
The greenhouse gases produced by human activity continue to increase despite worldwide concerns. The contribution of the various greenhouse gases to the world's production is divided between carbon dioxide (76 per cent), methane (16 per cent), nitrous oxide (6 per cent) and other gases (2 per cent).
Farmers can slow down the emission of carbon dioxide by using electricity from renewable sources, by using cars and road transport less and by planting trees faster than they are cut down.
Research on ways to store carbon in the ground continues at the NZ Biochar Research Centre at Massey University but currently no mitigations are available to farmers.
The focus for New Zealand farmers has mainly been on methane and nitrous oxide. Cattle and sheep produce methane when they digest feed in their rumen and then belch it out into the atmosphere. Because 35 per cent of the greenhouse gas emissions from NZ are from livestock, a decrease in methane will send a signal to the world that we are doing our bit for the planet.
We are certainly doing a lot of research on methane reduction. The New Zealand Agricultural Greenhouse Gas Research Centre and its many partners have increased our understanding of how methane is produced by livestock.
Potentially, we can develop vaccines to decrease methane production.
Potentially, we can breed sheep that produce less methane. But for now all a farmer can do is use high quality forage so livestock produce less methane for each kilogram of meat or milksolids produced.
Some of you will say ''why not just decrease the number of sheep and cattle in New Zealand?'' I cannot see the logic in this approach. The demand for meat and milk will not go away; somewhere elsewhere in the world will pick up the slack and the planet will be no better off. So for the moment, farmers can plant trees, feed livestock methane efficient forage and wait for research to provide better mitigation tools.
* Peter Kemp is head of Massey University's Institute of Agriculture and Environment.