1000 ppm is in the ballpark of what geochemists who study possible early Earth atmospheres say the CO2 level might have been 4 billion years ago, when the sun was 30 percent weaker (at least one source posits 1000 ppm CO2 and 1000 ppm methane). (dotearth.blogs.nytimes.com)
Upon arrival at Coconut Palms on the Bay, you will be greeted by the friendly staff who have created a very down to earth atmosphere so you can relax and unwind. (discoverherveybay.com)
Using the diagrams above, and assuming that the CO2 bar for Venus has a width of 600 pixels (the width used for the total Earth atmosphere), the height of just the CO2 would be 400 * 58.9 = 23,560 pixels. (mc-computing.com)