If I am mistaken, the Keeling Curve is an reading of CO2 levels in the air. At one point, Mauna Loa, a volcano in Hawaii. I'll leave why that is a probably a poor choice
Mauna Loa is only one of over 200 stations, ships, and planes that measure CO2, all of which show the same trend. It's also measured by satellite. The trend is robust.
http://www.esrl.noaa.gov/gmd/ccgg/images/obsmm.png[/quote]
A map of measurement sites: [url]http://www.esrl.noaa.gov/gmd/Photo_Gallery/GMD_Figures/ccgg_figures/tn/ccggmap.png.html[/url]
In any event, you can read all about why Mauna Loa was selected for the first observatory and how they can be sure they're measuring background CO2 rather than volcanic emissions here: [url]http://www.esrl.noaa.gov/gmd/ccgg/about/co2_measurements.html#data_selection[/url]
[quote]I mean, we have hard numbers right? We have percentages like 99%-99.5% of CO2 is from non-human activies. Anthropogenic is .5%-1%. Volcanic activity is .1% apparently. So we have to know the numbers right?[/quote]
It's impossible to get direct measurements of sinks and sources over the entire world. You have to estimate, but that doesn't mean you're just guessing. If you're interested, you can read the numbers and justification from the IPCC here: [url]http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-chapter7.pdf[/url]
We know from atmospheric CO2 measurements that an additional ~4 GtC (2 ppmv) is staying in the atmosphere every year, which indicates a 4 Gt/yr imbalance between sources and sinks. Since fossil fuels are so valuable, nations and industry tend to keep very good records of their extraction and use, which allows for high-confidence estimates of their contribution, which by itself is more than the annual imbalance.
Direct measurement of trends in carbon isotope ratios and oxygen/nitrogen ratios also allow for a separate method of estimating whether that imbalance is primarily coming from plants, fossil fuels, or volcanic/oceanic sources. Plants and fossil fuels have higher C12/C13 than volcanoes and seawater while fossil fuels are depleted in C14 compared to plants. Burning plants or fossil fuels also consumes oxygen in the process of making CO2, so by tracking changes in the O/N ratio you can also tell how much is being combusted.
[quote]Additionally, I believe it was posted earlier, anthropogenic CO2 emissions are down over 30% from the economic downturn., Why is that not showing up in any of those graphs? Or did they forget to 'adjust' accordingly[/quote]
Lots of reasons. First is that there doesn't seem to have been a 30% decrease in emissions.- [url]http://www.pbl.nl/en/publications/2010/No-growth-in-total-global-CO2-emissions-in-2009.html[/url]
Second is that the graph only goes up to 2008, so would barely encompass the start of the economic downturn, regardless of its impact.
Third is that the curve shows total CO2 in the atmosphere, so a 30% reduction in emissions would still mean that the curve was still growing at 70% of the rate it was the previous year. Even assuming that there really was a 30% reduction in emissions, the trend line for 2009 would still be increasing at roughly the same slope as in 1996. With emissions staying flat, the curve should go up at the same rate it grew in 2008.
[quote]MCary and greenbean, obviously being on opposite sides of the argument (both of which are admittedly way smarter then myself) seemed to both generally accept that 99.5% number[/quote]
It's not that I accepted the number, just that the exact values were irrelevant to the argument, so I didn't bother to look them up. The basic premise that humans are only a small percentage of total sources is true whether the exact value is 5% or 0.5%, and in either case is still irrelevant to the question of whether sources or sinks are in balance.
[quote]What do they mean by Storage in gigatons? Is that an annual thing?....Because of all those Storage numbers are fixed, wouldn't the Earth have 'run out' of storage a looong time ago? [/quote]
The black, "storage" numbers are standing stock, so they're the values for how much each reservoir holds. The total mass of C in the entire system is fixed, but the value in each reservoir is not. When you draw down one reservoir you transfer the same amount to a different reservoir (e.g. drawing down the fossil fuel reservoir adds to the atmospheric and oceanic reservoirs). The fluxes in purple are measurements of how much mass per year is being transfered from one reservoir to another.
[quote]I don't know if there's a cap on deep-sea storage, but Greenbean probably does.[/quote]
On geological scales, not really. All of the carbon we add to the atmosphere, even if we burn all the fossil fuels out there will eventually be locked back up as fossil fuels and carbonate rocks- after a few thousand years. On practical scales though, how much the oceans can take up is limited by mixing since only the upper mixed layer is actively absorbing atmospheric CO2.
[quote]Do you happen to know why 'Cement Production' is singled out?[/quote]
Because it uses a lot of energy to heat carbonate rocks like limestone until CO2 is driven off.
[quote]And going back to that Mauna Loa graph, I am not even more unsure how that works, or what it suggests...If in fact, the current CO2 levels are today around 390, how can the Earth process 366 of that (removing 6% of that for human emissions using your number), but when in 1974 it couldn't process all 310 of CO2 (natural + anthropogenic)? In 1974, Earth was only capable of processing 291 (310 - 6%). That doesn't make sense.[/quote]
I'm not sure if I'm interpreting what you said correctly, but it looks to me like you're making at least 3 mistakes.
First, you're confusing standing stocks and fluxes. The 390 ppmv value is the standing stock in the atmosphere, not how much is being processed per year. The 6% value you're using is a percentage of a gross flux (% of all natural and man-made sources, before sinks are considered), not a percentage of the standing stock, so you can't subtract it from the stock. They're different units.
The slope of the trend line of the curve is the annual increase, which is equivalent to net flux, i.e how much stays in the atmosphere per year from all sources minus sinks. In the 1960s the slope was 0.8 ppm/yr while it's about 2.0 ppm/yr now, indicating that more than double the amount of CO2 is staying in the atmosphere each year compared to 50 years ago.
And that leads to the second mistake, which is assuming constant emissions. We're currently responsible for 6% of total emissions or whatever value we decided on, but that hasn't always been the case. Emissions have been growing almost every year for decades, so each year our contribution to total emissions has become a larger percentage of the whole, only reaching 6% recently.
Finally, your calculation assumes that all of our emissions stay in the atmosphere, which isn't true. The estimate is that only about 45% of what we emit stays in the atmosphere, so our total annual contribution to the atmosphere is only 45% of that 6% of total sources.
What the curve shows is that CO2 has been increasing over the past 50 years and that the rate of increase has more than doubled over that time as well.
