ANALYSIS | You glide silently in your sleek new electric Tesla Model 3, satisfied you're looking great and doing your bit for the planet.

But keep going - you'll have to drive another 21,725km before you're doing less harm to the environment than a gas-guzzling saloon.

That's the result of a Reuters analysis of data from a model that calculates the lifetime emissions of vehicles, a hotly debated issue that's taking center stage as governments around the world push for greener transport to meet climate targets.

The model was developed by the Argonne National Laboratory in Chicago, USA, and includes...