But at the very beginning it's actually a negative because you've gone from a hunting gathering society where you're eating a lot of protein to one where maybe you're not eating as much protein and actually the life expectancy goes down in the beginning of the Neolithic Revolution as well does the height of the people. I think we shrank like six inches. It's ridiculous. But number one would be agriculture and with that comes changing your natural environment. That's a second effect. In order to have agriculture you're going to have to irrigate and move water. You're going to have to cut trees down and do deforestation.