Wednesday, November 7, 2012

Anthropogenic Global Warming - Part 5 - Total CO2 Output - FAILED


Frustrated chipmunk
This is a meta-commentary. The following post is my attempt to demonstrate that the direct measurable CO2 output from humanity is sufficient to account for the increase in CO2 levels in the atmosphere over the past 100 or so years.

What I found was that the numbers weren't adding up. This has me confused, and I decided to publish this as-is, and try again. The figures take a long time, and I need to double check them. Maybe I just made a math error, or maybe a figure I looked up is wrong.

For the sake of intellectual integrity, I have to acknowledge that my preconception that our emissions are sufficient to account for it isn't matching the numbers. I want to make sure I'm not cherry picking figures to satisfy a priori conclusions.

So I'll take another stab at this - but for the moment, I'm doing the equivalent to crumpling up this piece of paper and angrily throwing it over my shoulder.



I'm currently working on building an argument supporting Anthropogenic Global Warming, one chunk at a time.

Previous Parts:
Today's task - let's see how much CO2 our cars are emitting. Get ready for lots of math a figures.

Argument so far

Plants pull CO2 out of the atmosphere to build plant matter. 

Plant matter can die, be buried, and through a process called thermochemical conversion, turn into hydrocarbons, whether it's a liquid crude oil, natural gas or coal. This has been happening for at least 475 million years, with the amount of CO2 stored in the ground accumulating during that time.

The process of extracting fossil fuels and refining them produces a wide variety of types of hydrocarbons, all of which release CO2 into the atmosphere when burned, the amount of which varies depending on several factors, such as temperature and oxygen availability. The scientific community has done many studies about the CO2 (among other emissions) from internal combustion engines of various vehicles, in various scenarios. It's empirically demonstrable that our vehicles, among other sources, are emitting CO2.

The "greenhouse effect" is when gasses in the atmosphere absorb infrared radiation, much of which is radiated back from the Earth after the broader spectrum of electromagnetic radiation bombards the surface from the sun. Absorbing the infrared energy heats up these gasses, and in turn, the rest of the atmosphere.

We can demonstrate that CO2 is a greenhouse gas in laboratory experiments, as well as studying a wide variety of gasses in the atmosphere, so we can compare. Our understanding of the nuances of greenhouse gases is quite extensive due to the amount of research done.

Knowledge

The average estimated CO2 output per typical passenger car is 5.1 metric tons (5100 kilograms) per year. Some vehicles emit much more, and some much less. For conservative estimates, we'll say 2.5 megagrams per year. [1]

According to Ward's Auto World, the number of operational motor vehicles running in the world surpassed 1 Billion in 2010. [2]  For conservative estimates, we'll say there's 500 million active vehicles in the world.

That means that each year, assuming the number of vehicles and consumption remains the same in the 2010 estimates, our cars are emitting 1250 megagrams per year. The conservative estimates were half of the estimates found, which means that if the original estimates were accurate, the actual value would be four times that amount - 5000 megagrams per year.

How much is 1250 megagrams of CO2 in the grand scheme of things?

The density of carbon dioxide is 1.977 kg/m3 (gas at 1 atm and 0 °C, for the sake of averaging the upper-atmosphere temperatures with the ground temperatures) [4]

1250 megagrams of CO2 under those conditions would take up a volume of about 632271 cubic meters, or, better understood here in America as about 22104791 cubit feet. If the volume were a cube, the length of an edge would be about 281 feet.

So, each year, the sum total of cars pumps out about a 281ft x 281ft x 281ft cube of pure CO2 in gas form. Keep in mind this is a very conservative estimate.

That doesn't seem like much, but we need to consider it in terms of distribution through the atmosphere.

The total mass of the atmosphere is 5.1480*10^18 kg ± 1.5*10^15 kg [5] For the sake of conservative estimates, let's say it's 8.0*10^18 kg.

Let's assume (probably a safe assumption) that our CO2 output for a year is negligible compared to the total mass, so that when we add it, we can ignore the shift in "parts per billion/million".

For one year's output, the CO2, when mixed with the total atmosphere, would be measured at 15.625 ppb (parts per billion). As of June 2012, the CO2 levels in the atmosphere are measured at 395 ppm (parts per million) - or, 395000 ppb. [6]

That means our addition for one year would make up for about 1/25280th of the current amount.

Yes, this does seem low. Keep in mind, though, that I did conservatively estimate. If we look at the normal figures, the estimate changes to 97.125 ppb, or 1/4066th of it's current amount - which is about 6 times the previous amount.

Then, consider that our CO2 output from vehicles is about 25% of total global output (for 2007) [8]. Back to our conservative estimates, this means that the total human CO2 output would actually account for a 1/6320th of the current amount of carbon dioxide in the atmosphere. Meaning, it would take about 6320 years at this rate to generate the current CO2 levels from scratch.

We didn't start from scratch, though.

Before human industry started, the CO2 levels in the past thousand years were hovering around 275 ppm [9], which means that modern CO2 production only had to account for about  120 ppm.

Factoring that into our conservative estimates, that means that today's CO2 production would account for about 1/1920th. Our non-conservative estimate would have been 1/480th.

While gasoline usage has spiked in the past 60 or 70 years, human contribution has been significant for along while, mostly with things like coals and deforestation.

Personal commentary

One of the things I need to make sure I'm not doing is equivocating erroneously between "car", "motor vehicle", etc. It can start to get ambiguous what's meant by these terms, at times.

It takes me a few days to dig up information on this - to a frustrating amount. It might take me, depending on how distracted I am, an hour or so just to find out what percentage of global CO2 emission comes from transportation. The internet sucks like that.

I should probably have shown my work above (the exact calculations), but I figure it's simple enough to omit, until specifically needed.

Works cited

[1] http://www.epa.gov/oms/climate/documents/420f11041.pdf
[2] http://wardsauto.com/ar/world_vehicle_population_110815 (Note - find better source?)
[3] http://www.epa.gov/ghgreporting/documents/pdf/2010/2010data-factsheet.pdf
[4] http://en.wikipedia.org/wiki/Carbon_dioxide
[5] http://www.cgd.ucar.edu/cas/Trenberth/trenberth.papers/massERA40JC.pdf
[6] http://en.wikipedia.org/wiki/Carbon_dioxide_in_Earth's_atmosphere
[7] http://www.epa.gov/climatechange/ghgemissions/gases/co2.html
[8] http://metrostudies.berkeley.edu/pubs/reports/Carbon%20in%20Motion-UC-Final.pdf
[9] http://www.globalchange.gov/publications/reports/scientific-assessments/us-impacts/full-report/global-climate-change

No comments:

Post a Comment