Nearly two years ago, I wrote that transportation was “the leading contiributor to greenhouse gases (GHGs) in the country, according to a report by the U.S. Department of Energy (DOE), and… the fastest growing contributor.”
Now, in other terms and looking at additional factors, NASA has determined that automobiles are the largest net contributor to climate change pollution.
In other words, when you take into account the climate change (or global warming) gases automobiles emit as well as gases they emit that have a cooling effect, automobiles are the largest contributor to climate change, followed by 2) burning of household biofuels (i.e. wood and animal dung) and 3) raising livestock.
The NASA study reports:
“Cars, buses, and trucks release pollutants and greenhouse gases that promote warming, while emitting few aerosols that counteract it. In contrast, the industrial and power sectors release many of the same gases—with a larger contribution to radiative forcing—but they also emit sulfates and other aerosols that cause cooling by reflecting light and altering clouds…
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.”
Now, we all know a lot of work is going into creating greener cars. However, as someone trained in sustainable urban planning, I think getting out of the automobile habit altogether would be a great step forward for our society and the world. It would address this #1 climate change (and ocean acidification) concern, but it would also help address obesity tremendously, the economy, and other things. As Alex Steffen of Worldchanging writes, “we already know that the way to solve the problem of cars is to build better cities.”
I think we should take this opportunity to consider how we could live without cars, how we could help create a transformation of our transportation and urban systems. This is one of the first steps we need to take to address critical societal concerns of each the environment, health and the economy.
Image Credit: Atwater Village Newbie via flickr under a CC license