The kicker for Earth is that it's a lot easier and cheaper to make CH4 from biological sources (fossil fuels, fermenters, etc), so nobody does it at scale. All

The kicker for Earth is that it's a lot easier and cheaper to make CH4 from biological sources (fossil fuels, fermenters, etc), so nobody does it at scale. All the solutions (IIRC) need high temperature and a catalyst, which isn't surprising as we're un-burning rocket fuel. With cheap plentiful solar energy it's more practical; as Mars has no bio-sources of scale it's essential.