Another possibility is that an increasingly active sun is warming the surface. Danish, British, and American scientists have found that there is a strong relationship between the sun's cycles and the Earth's surface temperature. Not only is the Sun getting hotter over time, but when it does it also keeps clouds from forming as fast, and clouds cool the Earth. Fewer clouds, hotter Earth. You exhale carbon dioxide.
Plants take in carbon dioxide and use it as food.
A lot of scientific studies have shown that higher levels of carbon dioxide in the air increase plant growth and improves their efficiency of water usage. Burning fossil fuels releases carbon dioxide, which benefits plant life but does no demonstrable harm to climate. Clinton and Gore both claim that the science is settled, and that it shows we are warming the planet and will cause severe problems if we don't stop. Clinton and Gore are lying again. No surprise there.