Given that our economies are built off of the idea of infinite growth and increases in consumption, there's likely to be conflict involved.

I'd phrase it as "reduce the number of mouths to feed". That way it could be achieved by reducing the amount of cattle grown for meat and we could eat more grains etc... ourselves instead of feeding those intermediaries.

>> One of the best solutions to out fossil fuel problems

Mankind has survived just fine since ancient times without burning anywhere near the amount of fossil fuels burned over, say, the last 200 years.

With wind and solar, we are an the cusp of extremely cheap electricity.

>> is to simply have less people.

Feel free to follow your own advice.