CO2 is a potent greenhouse gas. What are they going to do with it? If they just vent it to the atmosphere, Lord help us.
Also, water and seawater are finite. I shudder when I read about countries and cities switching to Reverse Osmosis on seawater to get their drinking water. The crap they filter out is dumped back into the sea, causing higher salinity and concentrating chemicals in the sea.
Here is a graphic that shows how much water our Earth really has.
Spheres showing:
(1) All water (sphere over western U.S., 860 miles in diameter)
(2) Fresh liquid water in the ground, lakes, swamps, and rivers (sphere over Kentucky, 169.5 miles in diameter), and
(3) Fresh-water lakes and rivers (sphere over Georgia, 34.9 miles in diameter).
Credit: Howard Perlman, USGS; globe illustration by Jack Cook, Woods Hole Oceanographic Institution (©); Adam Nieman.