Scientific facts cannot be denied

IN his recent column (February 10th) Anton Coaker argues that methane emissions from livestock are not ‘comparable’ to methane emitted from the fossil fuel industry. This is certainly true, because the amount of methane originating from fossil fuel production and use, which is calculated in the global carbon budget (https:// www.globalcarbonproject.org/ carbonbudget/) as between

111 and 128 TgCH4/year, is only approximately half of that originating from agriculture and waste at 206-217 TgCH4/year.

Since the industrial revolution, methane concentrations in the atmosphere have increased by ca. 2.5 times due exclusively to human activities of which agriculture and waste has made, and continues to make, the largest contribution. In fact, domesticated ruminants are the largest source of anthropogenic methane, contributing an estimated 28% of annual global production.

In the UK, government statistics for 2019 (https://www.gov.uk/ government/statistics/agriclimate-report-2021/agri-climatereport-2021) reveal agriculture accounts for 47% of all CH4 emissions and of this 84% originates from enteric fermentation in livestock.

The argument that emissions of methane from cows is somehow ‘natural’ and involved in a ‘shortterm’ cycle which is not adding to global warming is frankly scientifically bogus.

Molecules of CH4 emitted from cows, from fossil fuel use or from any other source survive in the atmosphere for approximately nine years and have the same warming potential on the earth’s atmosphere.

CH4 is the second most important non-condensing greenhouse gas affecting the Earth’s climate, and the contribution of domesticated ruminants to CH4 emissions is highly significant.

Unfortunately, these facts based on scientific study cannot be gainsaid, however much Anton Coaker wishes they were not true. Professor Bruce Webb

Exeter, Devon