Atmospheric methane is turned into fish food

Researchers at Stanford University have studied an innovative process that could partly contribute to reducing atmospheric methane: a system of bioreactors containing bacteria fed with methane taken from the atmosphere, oxygen and other nutrients that can provide a protein food for farmed fish. The researchers found that this methane sequestration system is much more efficient than other methods that attempt to remove this pollutant from the atmosphere. Moreover, the resulting food costs less than what is generally used, consumes fewer resources such as water, soil and fertilizer, and also has a higher protein content. The study was recently published in the scientific journal Nature Sustainability.

Remember that methane is the second most abundant anthropogenic greenhouse gas in the atmosphere and that its 100-year global warming potential is 25 times greater than that of CO2. Moreover, compared to CO2, its concentration has grown more than twice as fast since the Industrial Revolution. Extracting methane from the atmosphere could potentially help slow global warming in the coming decades. A 40% reduction could mitigate warming by 0.4 °C by 2050.

The process studied by Stanford scientists is already operational. Currently, the largest expense is due to electricity, accounting for 45% of the total. The bioreactor needs to be continuously cooled. Savings could be made by improving heat loss. This would make it possible to replace soya and other nutrients used as animal feed.