GWP* is misleading environmental measure

• Measuring GHG emissions
• food and meat accounts for a large proportion of greenhouse gas emissions
• Eating local makes only small improvement to your environmental impact

The world’s meat and dairy companies are pushing for a new way to calculate and report their methane emissions, arguing that it better accounts for the gas’s short-lived nature. For example, the gas typically has a lifespan of up to 12 years, compared to hundreds of years for carbon.

This is true but methane is much worse for the environment. It has around 28 times the impact of carbon dioxide over a 100-year period, and 80 times over a 20-year period.

GWP* could indeed be relevant for preparing emissions trajectories “to estimate the level of methane emissions that would still be consistent with a specific temperature trajectory”.

it is not valid for estimating specific country, company or farm emissions. even small emissions reductions could give a misleading picture of climate neutrality

Because the tool measures the rate of change in emissions, countries that increase livestock herds from a low base – often those in the Global South– would be seen as bigger pollutants than major emitters that have large but stable herds. Additionally, companies with high but stable methane emissions could claim to be climate-neutral or -negative based on minor reductions.

Developing countries could be penalised for even small increases in livestock production, while developed countries could be rewarded for tiny reductions in their herds

Tyson foods could achieve GWP* of 0 while still having emissions higher than the whole country of Peru.

GWP20 might be better

New York has switched to this metric to “reflect the severe short-term warming impact methane has and highlight climate benefits of rapid methane reductions”.