Actually more plants is how the earth restores itself. If you stop car production the green house gases still stay in the air. Then you have coal burning power plants that put sulfur, methane, mercury in the air. Then you have melting permafrost which just makes it worse. Carbon isn't the only pollutant. Stopping car production(the making of cars) wont solve everything. Global warming happens for other causes as well. Burning gasoline is just the most well known one to date. Reforestation takes longer but basics plants can do the job too. They all do photosynthesis so they will absorb the carbon. For example ice is melting(obviously) and there is less white ice to reflect the light back into space so the dark blue ocean water absorbs the heat making the water warmer. When ocean temps rise hurricanes get stronger (Irene and Sandy). Cars play a role but start with plants and then to coal plants and while finding alternative fuel sources. This will remove some gases from the air allowing more light to escape.

A volcano can give off something like 10 times what every single car in the world gives out in a year, so things like this happen. Deforestation however, is a new thing we have introduced and I think is the major problem, I am busy will be happy to explain why sometime later!