Microwaves in Britain generate as much carbon dioxide as more than one million cars, scientists have concluded as they call on people to use the ovens more efficiently.
Over and above the mistake already pointed out (comparing total life emissions for microwave ovens to cars only in direct use) two more.
1) How much CO2 they produce in use, the thing that we are told we should be more careful about, depends upon the inputs into the electricity generation system. As is true of electric cars or electric trains.
2) What’s the opportunity cost? Or in this case, perhaps opportunity benefit? What would be the emissions from having hot and or cooked food – a pretty reasonable human desire – without microwave ovens?