wait: they are going to calculate a carbon tax at the border and apply it to imports, right?
otherwise, this is going to hurt local farmers, and actually incentivize the wrong behaviour, as consumers will pay on the gas used to drive the tomatoes down the street, but not on the cost to ship them from mexico. so. that will actually make imported fruit less expensive, which is backwards.
the idea is to stop shipping goods around all over the place when it's not necessary to. so, that import tariff is necessary, or this is pointless.