Tuesday, January 26, 2010

Tangled Web of Carbon Emissions

The UN published an eye-catching and educational graphic that illustrates society's sources of carbon emissions as well as the use that generated those emissions and the kind of emissions they are. You can pull a boatload of surprises off this one. Here are a few that surprised me. (All values are computed based on CO2 equivalent tonnage.)

Energy Consumption accounts for only 61.4% of total emissions. This is still the vast majority, but not as much as I thought it was. Land Use change is the second largest source at 18.2%. There's cause for thought.

Methane, which is 21 times more potent than CO2 as a greenhouse gas, comes mostly from three sources Ð Agriculture 53.6%, Waste 25.7%, and the Oil Industry 20.7%. So a focus on those would be very effective.

Agricultural Energy Use is only 1.4% of the worldwide total emissions. So despite all the programs to reduce farm-based energy consumption, that really doesn't seem to be a problem. Much greater are the Agriculture Soils category, which I assume includes fertilizer applications, at 6%, and Livestock & Manure at 5.1%.

Transportation accounts for 13.5% of emissions, although I know that varies greatly from place to place. Here in the Pacific Northwest, with our blessing of hydropower, transportaion emissions are about half of our total.

Transportation Sectors
surprising than the Transportation total is the breakdown by sectors. Road travel accounts for 73.3% of Transportation sector emissions (9.9% of the world total.) Air and Rail make up the other 27% (11.8% and 14.8% respectively. Electric rail accounts for an additional 0.3% of world total, but it is counted under power plant sources.) The point here is that a fcous on road systems, either in reducing the usage or increasing efficiency or both, will yield the greatest benefit.

Nitrous Oxide
, the second most harmful greenhouse gas, is produced almost entirely by Agricultural Soils. Nitrous accounts for only 8% of the world's GHG production, but 75% of it comes from Soils, which generally means evaporation of synthetic fertilizers. So here's a significant chunk of emissions that can be stopped with a singular focus.

My take away here is one of hope. With focused efforts it's possible to reduce emissions pretty readily. There is a tougher challenge politically of course. But still, the research story is a positive one.

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Janos Szécheny said...

I assume you didn't mean it to come off this way, but someone who doesn't look at the fine print might assume that you mean that the methane output bar should be multiplied by 21%. When reading the graph, one should note that the graph reports the output in CO2 equivalent emissions, not volume. I agree though, there could easily be a focus (and one is beginning) to capture methane from landfills, which can then be used as fuel. Ag is a little more difficult, except where cows are being housed in lousy, indoor factory farms. I'm not sure if that is the source of all ag methane, but I think a large amount of it.

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