Microbes may be masking true scale of methane emissions

A team of US scientists has discovered that methane-producing microbes can change the chemical “fingerprint” of the gas they emit, making it harder to tell exactly where it comes from.

Methane is a powerful greenhouse gas, with about two-thirds of emissions coming from microbes living in oxygen-free places such as wetlands, rice fields, landfills and the stomachs of cows. Scientists often identify the source of methane by studying the ratios of heavier and lighter forms of carbon and hydrogen in the gas.

Researchers at the University of California, Berkeley, used CRISPR gene-editing to adjust a key enzyme inside these microbes. They found that when the enzyme’s activity dropped, the microbes altered how they processed their food, swapping hydrogen atoms with water in the process. This changed the gas’s chemical signature.

The study, published in Science, suggests some microbe types may be responsible for more methane than previously believed, and could help refine how scientists track and reduce emissions.