What three (or more) things would you change to improve life on the earth?

Imagine you were given supreme control over everything in our galaxy except the planet earth and it’s living beings. That is, you could control the sun, all planets, asteroids, and comets in the solar system, and all the stars and their planetary systems in the galaxy. What three (or more) things would you change to improve life on the earth? For each, you much provide why/how the change would improve life based upon scientific reasons as to how the change affects life on earth.