I know how to make mars a second earth. its simple since there already is sufficient evidence to say mars was once very much like our beloved planet. To recreate this ecosystem we first must increase the atmospheres temperature which would in turn melt the ice caps and fill the oceans which would re start the water cycle. How we do this is simply take one of our mistakes on earth and use it as a good thing. this mistake is called the greenhouse effect. We must create sufficient pollution by exploding a thermonuclear device. And then we could take phytoplankton over and deposit them in the ocean which would cause the amount of carbon dioxide in the atmosphere and make it more hospitable. Then we could bring lots of shiploads of plants and insects and animals all this would take a lot of time but in a couple of hundred years it would be basically a second earth