@julieca you know who actually has the power to put pressure on firms, through targets and legislation - the government.
Do you know who doesnt have power to put pressure on firms - children, women in abusive relationships, disabled people, the elderly, people living in poverty, all the people disadvantaged by your idea.
There are plenty of other ideas on here that are much better.
You know what else would reduce carbon emissions - a four day working week - less car travel needed, less carbon emissions on heating buildings, lighting them, powering computers etc. You know who benefits from that - women with children (less childcare needed), disabled people (who may be able to work 4 days where they cant work 5 and part time jobs are hard to find, or who may have more family around to look after them instead of having to rely on carers so have a better quality of life), the elderly - again more scope for care and social visits and a better quality of life., people living in poverty as it may be easier for them to have the time to pick up a second job, or give them the time to study to improve their employment prospects or have to pay less childcare, or cook better meals etc. Unfortunately it could detriment people in abusive relationships.
However in general if you look for ideas that get big businesses to do whats necessary rather than penalising people in society who are penalised enough by this government then you may actually come up with a realistic solution.
One study by the way says that data centres are responsible for as much carbon emissions as global aviation. So cutting down on flights by increasing data storage requirements is a bit of an own goal...