LowEmissionAsphalt-136pg-WhitePaper-May2023

P a g e | 32 Much as in other tier one (advanced) countries such the United Kingdom or the European Union (EU), U.S. transportation emissions are now the largest lone source of anthropogenic carbon. More than eighty percent (80%) 57 of transport sector emissions come from motorized vehicles. Though CO 2 is found only in trace amounts in the Earth atmosphere, with a concentration of ~0.05%, 58 it plays a catalytic role in our climate known, of course, as the greenhouse effect 59 which simply describes the trapping of heat near the Earth’s surface . This amount of CO 2 presents a temperature delta of + 85°F 60 on Earth and why any changes in CO 2 concentrations can have a large impact on weather. Figure 14 – CO 2 Concentration Rising 1960-2020 Source: UC San Diego; Scripps Institute of Oceanography As solar energy bombards the planet it is well organized and pierces its way through the stratosphere and troposphere to the Earth surface. However, once reflected or 57 EPA. 58 Chang R and Overby J, 2017. 59 greenhouse effect is the trapping of the Sun’s energy in a planet’s lower atmosphere, due to the greater transparency of the atmosphere to visible radiation than infrared radiation emitted from the planet surface. 60 Chang R and Overby J, 2017.