They're cleaner, no doubt. But are they clean enough that a 1-1 replacement could avert massive ecological destruction à la global warming? No they are not.
They are a bridge towards lowering emissions but they cannot get us to zero or negative emissions. For as long as they are in use cars will simply remain "part of the problem". Acutely, personal vehicles used for quotidian trips are a large part of the contribution towards carbon emissions and can easily be phased out with improved urban and residential design patterns, public/collective transport infrastructure, and low-tech solutions like bikes, draft animals, etc .
They are a bridge towards lowering emissions but they cannot get us to zero or negative emissions. For as long as they are in use cars will simply remain "part of the problem". Acutely, personal vehicles used for quotidian trips are a large part of the contribution towards carbon emissions and can easily be phased out with improved urban and residential design patterns, public/collective transport infrastructure, and low-tech solutions like bikes, draft animals, etc .