A greenhouse gas is a gas with a molecular structure that causes it to absorb and emit infrared radiation When incoming radiant energy from the sun is absorbed by the Earth's surface and reemitted as infrared energy, greenhouse gases in the atmosphere prevent some of this heat from escaping into space, instead reflecting the energy back to further warm theThis chart shows the change in global greenhouse gas emissions over time Greenhouse gases are measured in 'carbon dioxideequivalents' (CO 2 e) Today, we collectively emit around 50 billion tonnes of CO 2 e each year This is more than 40% higher than emissions in 1990, which were around 35 billion tonnes Carbon dioxide concentrations have increased substantially since the beginning of the industrial era, rising from an annual average of 280 ppm in the late 1700s to 410 ppm in 19 (average of five sites in Figure 1)—a 46 percent increase Almost all of this increase is Untitled Document Which would increase the amount of gre...