>>14233600If you want to improve the global environment, humans being less wasteful would be a simple yet effective approach. This means less consumerism and planned obsolescence. It also means humans must be more efficient. One way to maximize human efficiency leading to a decrease in the toll on nature from the modern lifestyle would also require genetic modification like you suggest, but in this case it's to make males small and lean. The savings in calories and food alone to feed an equivalent population of small males would be invaluable. Such a society of small males and large females would be much more efficient, intelligent, and productive leading to a greatly improved ability to respond to the challenges, problems, and issues challenging the modern world.