From Meteorology to Mitigation: Understanding Global Warming

Current Emissions by Sector: Transportation


Transportation, as we have seen, accounts for 13% of fossil fuel emissions. Historically, the vast majority of these emissions have come from the road (cars, trucks, SUVs, motorbikes, etc.), and much of the recent growth is related to freight trucks, but emissions from air and sea transport are increasing (much of it is also related to freight transport), and emissions from airlines are projected to become increasingly significant in the decades ahead.

Historical and projected transport emissions by Road, Air, & Sea 1970-2050 - all slowly rising in emissions
Figure 12.8: Historical and Projected Transport Emissions by Mode 1970-2050.
Credit: Dire Predictions by Mann & Kump

As with the energy sector, transport-related emissions from the developing world, especially China, but also South America and the former Soviet Union, are projected to become increasingly important as these nations develop their transportation infrastructure and adopt driving patterns similar to the developed world.

Projection of transport energy consumption by region 2000-2050 - lowest in U.S., Canada, and Alaska.
Figure 12.9: Projection of Transport Energy Consumption by Region 2000-2050.
Credit: Mann & Kump, Dire Predictions: Understanding Climate Change, 2nd Edition
© 2015 Pearson Education, Inc.

There has been quite a bit of discussion about the prospects for so-called Peak Oil taking hold in the decades ahead, as conventional oil reserves begin to run dry. Such predictions are based on the idea of Hubbert's Peak, which uses a simple theoretically-derived expression for the time evolution of production from individual wells, combined with estimates of the declining rate at which new wells/reserves are discovered over time, to project global petroleum production over time. One often encounters the argument that the peak oil phenomenon will serve as a solution to the carbon emissions problem. This argument is flawed, however. While it is true that conventional petroleum reserves could begin to run dry in the years ahead, there are other unconventional reserves in the form of tar sand and oil shale, which could provide a century or more of additional petroleum supplies—of course, such reserves may be considerably more costly to recover. Thus, it is ultimately going to be a matter of economics—as discussed earlier in this lesson—as to whether or not petroleum-based energy will be able to compete with alternative technologies (hydrogen cells, electric vehicles, bio-fuels) for transportation.

A traffic jam is seen during the rush hour in Beijing
Figure 12.10: A traffic jam is seen during the rush hour in Beijing.
Credit: China Daily