He says NZ farmers are renowned for doing a good job around climate change issues and they should be more incentivised.
A professor and air quality specialist in co-operative extension in the Department of Animal Science at the University of California, Mitloehner presented a webinar with the NZ Roundtable for Sustainable Beef (NZRSB)
He pointed out that NZ farmers are part of the solution when it comes to climate change, and policymakers could better acknowledge and respect that.
“If you run a policy that makes farmers want to give up, then whatever livestock products are produced in NZ as a result, will then come from elsewhere in the world,” he said.
“Will the products from places that pick up the slack be as efficient and environmentally conscious as your farmers?
“This kind of leakage is the last thing you want.”
He says NZ farmers are known for doing a really good job, so you want them to keep doing it, and to quantify it appropriately.
“I recommend they are incentivised to work even harder along these lines,” he said.
“It is important to keep your eye on the ball, and that ball is warming. It is not about a carbon footprint, it is about a warming footprint.”
Mitloehner says NZ would be well-served by looking at what the impact of its livestock has been over the years.
“What is the warming footprint of NZ’s beef, dairy and other industries?” he asked.
“You will never get the answer to that question by using the traditional method of measuring greenhouse gas emissions, Global Warming Potential 100 (GWP100).”
GWP100 was developed in 1990 and the science has moved on. GWP100 assumes all GHGs are cumulative, that is, they never reduce. While this is correct for carbon dioxide and nitrous oxide, methane is a flow gas and has a lifespan of about 10 years before it disintegrates.
Mitloehner says that GWP100 will not provide the answer to NZ’s warming footprint, but using GWP* will.
GWP*, a new more accurate approach to measuring methane emissions, recognises that methane survives in the atmosphere for 10 years, whereas the other two main greenhouse gases survive for thousands of years.
For countries with high methane emissions, this can make a big difference in how reducing emissions is understood and progressed.
“This is not some kind of greenwashing or creative accounting,” he said.
“GWP* uses GWP100 in its formula, but it looks at it over time.”
GWP* means that if herd numbers remain the same after 10 years, then methane levels remain constant, with the quantity emitted equaling the quantity disintegrating.
The NZRSB is supportive of the GWP* approach.
“The GWP* approach is gaining traction around the world and if NZ wants to be a world leader in this space, it is time we started using an accurate measure that correlates to actual warming,” NZRSB chair Grant Bunting said.
Bunting says modifying the use of GWP so that it accounts for the differences between short-lived and long-lived gases will better connect emissions and warming.
“If all GHG emissions are treated the same, as they are using GWP100, short-lived emissions are unequally accounted for,” he said.
“As we learn more and the science develops, we need to ensure our approach remains relevant.”
Watch the webinar here: https://www.nzsustainablebeef.co.nz/media-releases/rethinking-methane
