Morrisons is to have its cows given additives of seaweed in an attempt to reduce methane emissions.
This additive reduces methane emissions by as much as 80%, and given that morrisons currently has roughly 10% of the country shopping there, they have the potential of reducing cow based emissions by 8%. Now other brands need to follow Morrisons lead on this, but about 5% of the UK emissions is accounted for by the emissions of cows, which means that Morrisons move alone, should cut carbon emissions in the UK by around 0.5%, now while this is not huge, if everyone across the country chose to use this meat, 5% of emissions is a pretty substantial cut.
More to the point, with the main supermarket chains in such close competition in the UK, I find it hard to believe that others are not going to follow Morrisons lead. I for one will be happy to get our beef from Morrisons (though in our case, we have already replaced most of our beef mince with turkey mince which has a far lower carbon footprint anyway.