These emissions are what are called Scope 3 emissions from the gas companies. They are responsible for them because they are the foreseeable emissions that result from their sale of gas. That’s what Scope 3 means – they are the emissions caused by what you sell rather than what you do yourself. They should as a result account for them and the cost of their removal within the supply chain they manage under what I call sustainable cost accounting. If they had to do so then they would be starting to sell heat pumps now.
Gas companies should be selling the heat pumps which don’t use gas?
BP should be selling you the shoes you’ll need for Shank’s Pony? The butcher should be selling you the beans for your vegan diet? Ryanair should be selling train tickets?