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.
As previous posts on planetary boundaries made clear, any schema of categorization is bound to have flaws and limitations. As those posts also made clear, identifying sources of GHG emissions or causes of climate change is not sufficient in seeking to understand the forces driving the intersecting climate and ecological crises (for simplicity: the climate crisis) now unfolding on Earth. That being said, it’s not my intention to attempt to rewrite the Fifth Report (AR5) of the Intergovernmental Panel on Climate Change (IPCC), and so I will simply rely on the schema of the same in briefly pointing to the economic sectors responsible for the lion’s share of global anthropogenic GHG emissions (though please bear in mind that AR5 was published in 2014 and was backward looking so is already nearly a decade out of date as reflected by the 2010 date in the graphic below).
To that end, next week, in following the IPCC’s framework, I plan to briefly discuss, in descending order of contributions to global GHG emissions: 1) the energy sector; 2) agriculture, forestry, and other land use (referred to, in AR5, and elsewhere, as AFOLU); 3) industry; 4) transport; and 5) the building sector. Such a ranking of contribution to GHG emissions does not take into account “indirect emissions” (that is, “emissions from electricity and heat production [that can be] attributed to the sectors that use the final energy”) and considering indirect emissions changes the ranking significantly.
Posts next week will get into some of these issues, but for now, I give you as both conclusion and bonus material, the following pie chart (with its original caption) from AR5 of the IPCC, depicting both the GHG emissions by sector, and – in the expanded “Electricity and heat production” section – the breakdown of sector-wise indirect emissions: