Graphic The relentless rise of carbon dioxide Ancient air bubbles trapped in ice enable us to step back in time and see what Earth's atmosphere, and climate, were like in the distant past They tell us that levels of carbon dioxide (CO 2) in the atmosphere are higher than they have been at any time in the past 400,000 years Greenhouse gases that occur both naturally and from human activities include water vapor, carbon dioxide (CO 2 ), methane (CH 4 ), nitrous oxide (N 2 O) and ozone (O 3) Other greenhouse gases have essentially no natural sources, but are side products of industrial processes or manufactured for human purposes such as cleaning agents Graph by NOAA Climategov based on data from NOAA ESRL According to the 19 AGGI report, the combined heating influence of the longlived, humanproduced greenhouse gases is 314 Watts for every square meter of Earth's surface Just over 80 percent of that is due to carbon dioxide (66%) and methane (16%) Global Greenhouse Gas Emissions...