A molecule of carbon dioxide (CO2) consists of one carbon and two oxygen atoms. Colorless and odorless, it is hard to detect. Compared to improvements in reducing the emissions of toxic pollutants, there has been less progress with reducing CO2 from cars. In total humans emit around 32 gigatons of carbon dioxide each year. Half of this stays in the atmosphere; the rest is absorbed by oceans and vegetation. With sharp increases in man-made CO2 emissions, the natural CO2 cycle gets thrown out of balance. Vegetation can no longer transform the increased amount of CO2 into oxygen, and oceans are steadily reaching saturation level. The increase of carbon dioxide in the atmosphere results in an enhanced greenhouse effect and subsequently climate change. While CO2 is only responsible for 20 percent of the natural greenhouse effect, it accounts for about 60 percent of the anthropogenic greenhouse effect that is causing the latest wave of global warming.