To summarize, climate crisis is the defining issue of the century. Buildup of anthropogenic greenhouse gases (GHGs) in Earth’s atmosphere is driving global heating, while a convergence of global crises threatens to rupture key planetary boundaries beyond which organized human life on Earth would be threatened. Although the human activities which drive these converging crises (for simplicity: the climate crisis) are diverse and complex, the Fifth Assessment Report (AR5) of the Intergovernmental Panel on Climate Change (IPCC) offers a high level categorization of the sources of anthropogenic emissions. Pieces thus far in this subset of primers have focused on the energy sector (the largest single contributor to anthropogenic GHG emissions at 35% in 2010 according to the IPCC), agriculture, forestry, and other land use (or AFOLU) (the second largest contributor at 24% in 2010), and industry, the third largest, at 21%.
Today’s piece centers the fourth largest contributor, transport, which contributed 14% of all anthropogenic GHG emissions in 2010. I think transport more or less speaks for itself. The only caveat is that, in some instances international bunkers (that is, the energy “consumption of ships and aircraft on international routes”) are carved out as their own category (and strangely, in the process, also not attributed to any country). As best I can tell, AR5 rolls emissions owing to international bunkers into the 14% for transport. As with all of the other high-level categories, transport is so broad as to be extremely hard to think about in a meaningful way, but at least breaking down the sources of GHG emissions into these five large buckets creates a slightly clearer framework for beginning to consider the character of the challenge of transitioning away from dependence on fossil fuels.