“Satellites have detected methane emissions from belching cows at a California feedlot...”
BS.
Methane has a very specific spectral signature in the infrared and near infrared bands. It is easily detectable from orbit. Humans have used the same spectral lines to look for methane on Mars and also into deep space on exoplanets. With high resolution multi spectral orbital imaging it would be easy to spot methane from space. This method is used to spot leaks in pipelines and also from tank batteries from airborne multispec and orbital as well. Tech has gotten down to the one meter resolution from orbit much less if you have access to classified imaging means.
I hold a master’s in remote sensing, and a National geospatial intelligence certification as well. So I’m a expert in this field. Sensing the methane is not all that hard. The question is does it matter on a planetary scale the likely answer is not at all given how much methane is released naturally from swamps, ocean seeps, ocean hydrates, permafrost hydrates act.