7 Smokestack Stats
Now that we’ve characterized the various heat-trapping gases, from carbon dioxide to methane and beyond, it’s time to point some fingers. We’ll identify the sources of each heat-trapping gas by sector. Because of the problems we identified with CO2-equivalent emissions, we’ll show emissions of each pollutant separately. Because of the vast inequality of emissions across the world, we’ll avoid terms like “human emissions” or “our emissions.” For more investigation of “Who’s To Blame,” you can read this chapter of my Climate, Justice and Energy Solutions text, including the story of how the concept of “carbon footprint” was popularized by the oil company BP.
The fossil CO2 emissions data above is from EDGARv7.0, and the deforestation (land use change) data is from the Global Carbon Budget 2021.
Let’s examine the transportation emissions by type: air, road, rail, maritime ships, and other.
Source: EDGARv7.0
Next, industrial emissions are broken down into their sectors: fossil fuels, manufacturing/construction, cement, the chemical industry, the metals industry, lime production, and other industry.
Source: EDGARv7.0
We can examine regional contributions to global emissions by plotting the per capita emissions in several world regions. The width of each area is proportional to population. The area of each box (population times per capita emissions) then gives the total emissions from that region.
The background lines in these plots are designed to help visualize the total emissions in each region. The thin dashed vertical lines separate 1 billion people, while the horizontal lines are plotted every 1 ton of CO2 per year. Thus, each rectangle in the background has an area of 1 GtCO2/year.
Population data is from the UN World Population Prospects 2022, and emissions data is from EDGARv7.0.
Here’s the breakdown of transportation emissions, in which one can see the exceptionally large American road transport emissions.
Population data is from the UN World Population Prospects 2022, and emissions data is from EDGARv7.0.
Industrial emissions by region show that manufacturing/construction emissions are a large fraction of each region’s emissions, while other sectors vary more with region.
Population data is from the UN World Population Prospects 2022, and emissions data is from EDGARv7.0.
To see the time-dependence of per capita carbon dioxide emissions from the different world regions, you can use the interactive plot below. Populations increase over the 52 year period, mostly in regions with low per capita emissions. Although only emissions since 1970 are plotted, you can see many major world events in the data, including the 1970s oil embargo, the fall of the Soviet Union, the 21st century rise of China, and the COVID-19 pandemic.
Population data is from the UN World Population Prospects 2022, and emissions data is from EDGARv7.0.
Interactive plots of 1970-2021 per capita emissions from transportation and industry by region are available as well.
Methane and More
Now let’s consider other heat-trapping gases, starting with the 2nd-larger contributor to radiative forcing, methane. Keep in mind that methane’s short lifetime of 11.8 years means that its warming effects can dissipate rather quickly. On the flip side, much of its current heat-trapping effect has resulted from its emissions from the last few decades. One might wonder whether the frequent climate damages lawsuits might target methane emitters soon, since these sources are perhaps liable for significant fractions of warming, even when only their recent emissions are considered.
A decent share of methane emissions come from fossil fuels. Livestock (ruminants and manure), waste (landfills and water treatment), and rice each contribute as well.
Emissions data is from EDGARv7.0.
Methane emissions, especially from non-fossil sources, are more evenly spread across the planet. Latin America has the largest livestock emissions.
Population data is from the UN World Population Prospects 2022, and emissions data is from EDGARv7.0.
Nitrous oxide is another important heat-trapping gas. With a lifetime of 109 years, it acts more similarly to carbon dioxide than methane over timescales typically considered in climate studies.
Nitrous sources are primarily from fertilizer application to agricultural fields. Nitrogen-based fertilizers are primarily made from petrochemicals using the energy intensive Haber-Bosch process. The nitrogen comes from the air, leading to increases in nitrogen content in the biosphere, which has its own environmental consequences. The heat-trapping effect is large as well. Many of the chemical industry emissions of nitrous come from production of fertilizer as well.
Emissions data is from EDGARv7.0.
Per capita nitrous emissions are largest in US/Canada, and as with methane, more equally spread among other regions.
Population data is from the UN World Population Prospects 2022, and emissions data is from EDGARv7.0.
Last chapter we detailed how CO2-equivalent is not a great measure, so don’t show anyone this plot of CO2e emissions by region! Or this animation!
Population data is from the UN World Population Prospects 2022, and emissions data is from EDGARv7.0.
