Absolutely transit and density are lower in terms of environmental impact. But I think that is a misconception to assume that they somehow lower GDP. In this case overall resources for housing and transit per capita will go down, but the net amount of resources isn’t going down (people aren’t getting paid any less). So any resources saved from higher density and transit, will simply be reinvested in something else, whether that be art products, higher quality foods, entertainment, etc.

I also think its a misconception to think that a lower exchange of goods is a positive thing. No woman or man is an island. The whole idea of comparative advantage is a simple, yet elegant way of using resources more efficiently and effectively. So a very low GDP could mean that we’re actually using more resources than we should be.

I think my overall point is that assuming GDP and environmental sustainability are somehow correlated is a fallacy.

I’d say a high amount of services being exchanged is a good thing. In our current world, with highly polluting unsustainable energy and material sources, having a high amount of goods being exchanged is a bad thing.

Transit systems and high-density buildings also take a large amount of resources to create. If the alternative is new roads and low-density buildings, that’s a net loss in GDP (especially over time) if you go with transit and density.

GNP is simply a measure of the flow of goods and services. Like all measurement tools it only gets at one aspect of a broader subject, in this case the health of our economy. It can only really be used in conjuction with other measures, such as personal health, and welfare statistics. (Not much different than CO2 emissions trying to measure the health of our planet)

On a very general level, having a high amount of goods and services being exchanged seems like a good thing. A very low GNP means things are stagnating and good ideas can’t get funded and realized. That certainly isn’t what we need if we’re going to retool our planet into a healthier, more sustainable world.

This is a synopsis of the best economics/policy book (well, one of them) that I’ve ever read:
https://blogs.law.harvard.edu/idblog/2008/03/18/book-review-development-as-freedom-by-amartya-sen/