NASA: Cars Greatest Net Contributor to Climate Change

A new study by led by Nadine Unger at NASA’s Goddard Institute for Space Studies (GISS) that analyzes the net climate impacts of emissions from economic sectors rather than by individual chemical species has found that on-road transportatation is and will be the greatest net contributor to atmospheric warming now and in the near term.

In their analysis, motor vehicles emerged as the greatest net contributor to atmospheric warming now and in the near term, with a total radiative forcing of 199 mWm-2 in 2020. The researchers found that the burning of household biofuels—primarily wood and animal dung for home heating and cooking—contribute the second most warming. And raising livestock, particularly methane-producing cattle, contribute the third most.

The industrial sector releases such a high proportion of sulfates and other cooling aerosols that it actually contributes a significant amount of cooling to the system. And biomass burning—which occurs mainly as a result of tropical forest fires, deforestation, savannah and shrub fires—emits large amounts of organic carbon particles that block solar radiation.