For example, an improvement of the nice residential building with solar panels that generate electricity (at least, to make it self-sufficient.. or positive) : of course, the improvement would be much costly.

Other example: off-shore wind-turbine

Tramways, which would be cheaper than a subway

Tourism: ecological lodge, green wild national parks or somewhat nature protected area
The tourist could be more sensitive to the pollution and quality of environment

Trend: bio, vegan, or trend of less-meat

Global constitution or decree: global improvement: all building and factories will be improved for energy-sparing, or equipped with solar-roof