> There will be an environmental impact, but it will be from hundreds of millions of humans not getting malaria and climbing their way out of property, not from the lack of mosquitoes in the ecosystem. It's still a significant problem, but our current solution of "let all the poor people die" is not a good one.

Ecosystem-wise, let's not forget mosquitoes and their diseases are as much threat as they are content. Hawaii didn't have mosquitoes until the 19th century, they did a number on native bird populations. Mosquitoes negatively affect any species they feed on, not just humans.