90% of soy grown worldwide is fed to livestock. Some is also used for fuel. Soy grown for human consumption is sprayed with less pesticides than that grown for feed and fuel. It takes about 12 kg of feed to produce 1 kg of beef.
So in the absolute "worst-case" where impossible burgers are made entirely of GMO soy, that's at least a 10x reduction in round up use.
To add to this, you are also removing the pesticides and antibiotics used in cattle farms and reducing land use. I can't wait until I can buy a 3 pound chub of Impossible Foods hamburger for cheaper than cow meat.
