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Friday, October 3, 2008

Al Gore, I'm waiting for my reward.

I have another Pascal's Wager on the topic of global warming: Regardless of whether you think global warming is primarily man-made, the last thing we should be doing is contributing to it.
But if we're going to correct global warming as fast as I think we need to, we sure as hell better make sure we do it right. So what is causing global warming, and what can be done to avert it?
Well, there are some handy charts and data in this report from the EPA - admittedly all the data is from 2002 and the US, but it does suggest that in that year, 83.4% of US greenhouse gas emissions were from carbon dioxide. Methane accounted for 8.6%, nitrous oxide 6.0%, and other stuff 2%. I'll focus on the first three, in part since they affect the climate in different ways; the report claims that methane is more than 20 times as effective as carbon dioxide in trapping heat, and nitrous oxide is over 300 times as effective as CO2, but also measures everything in terms of CO2 equivalents. Just because methane is more effective at causing climate change than CO2 per mass doesn't mean it actually outpaces CO2 and doesn't mean we should all go vegetarian, wannabe hippies out there, and if you wanna debate that I'm happy to open a Truth Court case. Even if it was contributing more to global warming than CO2, meat production isn't even the majority producer of methane and nitrous oxide - admittedly also produced in agriculture - would be an even worse problem. (Oh, and methane gets decayed after a few years anyway.)
I'm reducing CO2 to fossil fuel burning even though CO2 is emitted in other ways because fossil fuel burning made up 97% of gross CO2 emissions. (.9% came from iron and steel production, the closest competitor, and another .7% came from cement manufacture, totaling about 98.6%. Waste combustion, ammonia production, and lime manufacture were negligible parts of the emission of CO2 but I mention them because they nonetheless contrubuted more to global warming than other, non-CO2-producing factors I mention below. Gross emissions ignore carbon sinks.) Scroll down to Table ES-5; if I'm interpreting things right (let me know if I'm not, as I'm performing similar calculations throughout this post), about half of CO2 emissions from fossil fuel burning, as of 2002, comes from generating electricity, with half of the rest coming from transportation, and 59% of the rest after that coming from industrial operations. (Later, the report says 31% of CO2 emissions from fossil fuel burning came from transportation, 17% from industry, and the rest from residential and commercial uses, including electricity in that count. 40% of CO2 from fossil fuel burning came from electricity.)
The leading causes of methane production were landfills (32.3%), natural gas systems (20.4%), "enteric fermentation" or animal digestion (19.1%), coal mining (8.7%), manure management (6.6%), wastewater treatment (4.8%), and petroleum systems (3.9%). (That totals 95.8%. "Stationary sources" - wood-burning stoves mainly - was the largest remaining source at 1.1% with rice cultivation not far behind.)
69.1% of nitrous oxide emissions came from "agricultural soil management", with most of the rest (12.7%) coming from "mobile sources" (related to, say, motor vehicle internal combustion). Manure management (4.3%), nitric acid (4.0%), human sewage (3.8%), and "stationary sources" (3.4%) accounted for most of the remaining 18%. Other causes of climate change are primarily used as substitutes for chemicals that were eating away at the ozone layer, but we're now finding the cure isn't much better than the disease; the production of a byproduct of most air conditioning systems, and leaks from electrical transmission and distribution, also are problems.
So let's see... throw them all together... fossil fuel consumption accounts for about 80.9% of the total... N2O from agricultural soil management accounts for 4.1% to bring us to an even 85%... let's throw in the three leading methane producers, landfills (2.8%), natural gas (1.8%), and "enteric fermentation" (1.6%)... that brings us to 91.2%. Split up fossil fuel consumption into electricity, transportation, industrial fossil fuel burning, and residential/commercial fossil fuel burning (think natural gas or oil heating systems) and that's eight things to take care of and if we're lucky, we can make global warming something akin to a distant memory. We probably can't reduce emissions from all those sources to zero, so let's make it nine (which if I wanted to, I could split up into groups of three over the weekend) by throwing in "substitution of ozone-depleting substances" (1.3%). That makes up over 90 teragrams of CO2 equivalent, and nothing else accounts for more than 60 Tg CO2 equivalent, so it's a good stopping place. We could get rid of up to 92.5% of current global warming contributions right here on Da Blog!
Fossil fuel consumption is the 800-pound gorilla in the room and we'll get to that over the weekend, but for now, here are my thoughts on the others, for the sake of further reducing warming. Each section will start with some words on what the same EPA report has to say on the matter, followed by my own comments that boil down to whatever I could find out on Wikipedia and the report.
  • Soil management: Anytime nitrogen gets added to (or is even present in) soil, microbes convert at least some of it to N2O. So use of any fertilizer that contains nitrogen, "nitrogen-fixing crops and forages", dumping "crop residues and[/or] sewage sludge" onto soil, "high-organic-content soils", and yes, animal droppings could be contributing to global warming. I know this is one thing the vegetarians will seize on and claim the best way to be green is to go veggie, but honestly, given the importance of nitrogen in helping plants grow, I'm not sure there's much that can be done here. I mean, to get the most headway, we'd not only have to reject meat, but beans, corn, and barley (although less beer might be a cause for celebration) as well, not to mention rejecting any nitrogen fertilizer when that contains the most potential for sustainability. But don't worry, I'll throw in a few more things we can look at to make up for it: iron/steel production, "mobile sources" of N2O, coal mining, cement manufacture, and methane from manure management.
  • Landfills: Specifically, organic wastes such as yard wastes and food, which the microbes get into again. Recycling seems to be pretty strong in the United States, but composting as an environmental policy is only starting to gain steam. Some places have separate services for the collection of yard wastes. Also, according to the EPA report, many landfills, including the largest ones, collect the gas emitted by their landfills and combust them - which produces carbon dioxide, but again, CO2 is, all else being equal, much less of a warmer than methane. Still, stopping more stuff from going into landfills is the best approach here.
  • Natural gas: mostly methane. Some methane is leaked from petroleum as well because oil and gas are often found near each other, but gas is the major source. I'm not quite sure how that changes the relationships between the fossil fuels in terms of what's most polluting. Read on over the weekend to find out why this is just one beef I have with T. Boone Pickens.
  • "Enteric fermentation": Mostly applies to ruminant animals, so when you're eating pork or fowl, compared to eating beef you're actually helping the environment! Dairy might be worth foregoing, but improvements in efficiency have allowed cattle populations to decline from 1995-at least 2002.
  • "Substitution of ozone-depleting substances": This refers to chemicals called HFCs and PFCs, which are regulated by the Kyoto Protocol, being used as replacements for the last environmental panic, ozone-depleting CFCs, which were long used in refrigeration and firefighting. It's important that as alternatives are developed that don't harm the ozone layer or cause a greenhouse effect, they are spread to developing nations like China and India, and to the rest of the developing world, with all due speed.
  • Production of iron and steel: Here's something I had to go to Google to learn more about. Here's what I learned from here, from an International Energy Agency report: This is largely because a lot of coal tends to be used in the process, and improvements in efficiency can only continue to help. Some countries engage in "waste energy recovery" which can be used to generate power and help the overall fossil-fuel issue. This is another thing that will probably never significantly go away entirely.
  • "Mobile sources" of N2O: Fuel combustion can produce N2O in addition to CO2, which is one reason I don't trust biofuels. This will be one of my criteria when I look at alternative fuels for our cars: low nitrogen content, not just low carbon content.
  • Coal mining: Methane was produced when coal was formed and has been trapped since, and coal mining releases it. A lot of it is required by law to be directed to the atmosphere or else it'll blow up. Obviously this will become less of a problem as we reduce our use of coal, but methane recovery schemes are progressing in the meantime and surface mining has grown popular, if sometimes controversial.
  • Cement manufacture: CaCO3 (calcium carbonate) is heated and produces CaO and CO2, the former of which becomes part of the process of making cement. According to the IEA: China, which produces nearly half the world's cement, has gotten better at preventing too much in the way of CO2 emissions. Use of substitutes for clinker (unground cement) could improve CO2 emissions.
  • Methane from manure management: Basically, this means don't keep animal manure in an environment that doesn't allow oxygen to reach it. "Solid waste management" and cooler, drier conditions are better for taking care of manure.
So that takes care of nearly 20% of global-warming-causing emissions. Over the weekend, we'll look at the other 80%.

Many early voting registration deadlines are tomorrow, and trust me, it's not really as hard as you think it is unless your state is actively trying to get you not to vote.

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