April 30, 2009
What You Can(‘t) Do About Global Warming
Filed under: Climate Models, Climate Politics —
We are always hearing about ways that you can “save the planet” from the perils of global warming—from riding your bicycle to work, to supporting the latest national greenhouse gas restriction limitations, and everything in between.
In virtually each and every case, advocates of these measures provide you with the amount of greenhouse gas emissions (primarily carbon dioxide) that will be saved by the particular action.
And if you want to figure this out for yourself, the web is full of CO2 calculators (just google “CO2 calculator”) which allow you to calculate your carbon footprint and how much it can be reduced by taking various conservations steps—all with an eye towards reducing global warming.
However, in absolutely zero of these cases are you told, or can you calculate, how much impact you are going to have on the actual climate itself. After all, CO2 emissions are not climate—they are gases. Climate is temperature and precipitation and storms and winds, etc. If the goal of the actions is to prevent global warming, then you shouldn’t really care a hoot about the amount of CO2 emissions that you are reducing, but instead, you want to know how much of the planet you are saving. How much anthropogenic climate change is being prevented by unplugging your cell phone charger, from biking to the park, or from slashing national carbon dioxide emissions?
Why do none of the CO2 calculators give you that most valuable piece of information? Why don’t the politicians, the EPA, and/or greenhouse gas reduction advocates tell you the bottom line?
How much global warming are we avoiding?
Embarrassingly for them, this information is readily available.
After all, what do you think climate models do? Simply, they take greenhouse gas emissions scenarios and project the future climate—thus providing precisely the answer we are looking for. You tweak the scenarios to account for your emission savings, run the models, and you get your answer.
Since climate model projections of the future climate are what are being used to attempt to scare us into action, climate models should very well be used to tell us how much of the scary future we are going to avoid by taking the suggested/legislated/regulated actions.
So where are the answers?
OK, so full-fledged climate models are very expensive tools—they are extremely complex computer programs that take weeks to run on the world’s fastest supercomputers. So, consequently, they don’t lend themselves to web calculators.
But, you would think that in considering our national energy plan, or EPA’s plan to regulate CO2, that this would be of enough import to deserve a couple of climate model runs to determine the final result. Otherwise, how can the members of Congress fairly assess what it is they are considering doing? Again, if the goal is to change the future course of climate to avoid the potential negative consequences of global warming, then to what degree is the plan that they are proposing going to be successful? Can it deliver the desired results? The American public deserves to know.
In lieu of full-out climate models, there are some “pocket” climate models that run on your desktop computer in a matter of seconds and which are designed to emulate the large-scale output from the complex general circulation models. One of best of these “pocket” models is the Model for the Assessment of Greenhouse-gas Induced Climate Change, or MAGICC. Various versions of MAGICC have been used for years to simulate climate model output for a fraction of the cost. In fact, the latest version of MAGICC was developed under a grant from the EPA. Just like a full climate model, MAGICC takes in greenhouse gas emissions scenarios and outputs such quantities as the projected global average temperature. Just the thing we are looking for. It would only take a bit of technical savvy to configure the web-based CO2 calculators so that they interfaced with MAGICC and produced a global temperature savings based upon the emissions savings. Yet not one has seemed fit to do so. If you are interested in attempting to do so yourself, MAGICC is available here.
As a last resort, for those of us who don’t have general circulation models, supercomputers, or even much technical savvy of our own, it is still possible, in a rough, back-of-the-envelope sort of way, to come up with a simple conversion from CO2 emissions to global temperatures. This way, what our politicians and favorite global warming alarmists won’t tell us, we can figure out for ourselves.
Here’s how.
We need to go from emissions of greenhouse gases, to atmospheric concentrations of greenhouse gases, to global temperatures.
We’ll determine how much CO2 emissions are required to change the atmospheric concentration of CO2 by 1 part per million (ppm), then we’ll figure out how many ppms of CO2 it takes to raise the global temperature 1ºC. Then, we’ll have our answer.
So first things first. Figure 1 shows the total global emissions of CO2 (in units of million metric tons, mmt) each year from 1958-2006 as well as the annual change in atmospheric CO2 content (in ppm) during the same period. Notice that CO2 emissions are rising, as is the annual change in atmospheric CO2 concentration.
Figure 1. (top) Annual global total carbon dioxide emissions (mmt), 1958-2006; (bottom) Year-to-year change in atmospheric CO2 concentrations (ppm), 1959-2006. (Data source: Carbon Dioxide Information Analysis Center)
]If we divide the annual emissions by the annual concentration change, we get Figure 2—the amount of emissions required to raise the atmospheric concentration by 1 ppm. Notice that there is no trend at all through the data in Figure 2. This means that the average amount of CO2 emissions required to change the atmospheric concentration by a unit amount has stayed constant over time. This average value in Figure 2 is 15,678mmtCO2/ppm.
Figure 2. Annual CO2 emissions responsible for a 1 ppm change in atmospheric CO2 concentrations (Figure 1a divided by Figure 1b), 1959-2006. The blue horizontal line is the 1959-2006 average, the red horizontal line is the average excluding the volcano-influenced years of 1964, 1982, and 1992.
You may wonder about the two large spikes in Figure 2—indicating that in those years, the emissions did not result in much of change in the atmospheric CO2 concentrations. It turns out that the spikes, in 1964 and 1992 (and a smaller one in 1982), are the result of large volcanic eruptions. The eruptions cooled the earth by blocking solar radiation and making it more diffuse, which has the duel effect of increasing the CO2 uptake by oceans and increasing the CO2 uptake by photosynthesis—both effects serving to offset the effect of the added emissions and resulting in little change in the atmospheric concentrations. As the volcanic effects attenuated in the following year, the CO2 concentrations then responded to emissions as expected.
Since volcanic eruptions are more the exception than the norm, we should remove them from our analysis. In doing so, the average amount of CO2 emissions that lead to an atmospheric increase of 1 ppm drops from 15,678 (the blue line in Figure 2), to 14,138mmtCO2 (red line in Figure 2).
Now, we need to know how many ppms of CO2 it takes to raise the global temperature a degree Celsius. This is a bit trickier, because this value is generally not thought to be constant, but instead to decrease with increasing concentrations. But, for our purposes, we can consider it to be constant and still be in the ballpark. But what is that value?
We can try to determine it from observations.
Over the past 150 years or so, the atmospheric concentration of CO2 has increased about 100 ppm, from ~280ppm to ~380ppm, and global temperatures have risen about 0.8ºC over the same time. Dividing the concentration change by the temperature change (100ppm/0.8ºC) produces the answer that it takes 125ppm to raise the global temperature 1ºC. Now, it is possible that some of the observed temperature rise has occurred as a result of changes other than CO2 (say, solar, for instance). But it is also possible that the full effect of the temperature change resulting from the CO2 changes has not yet been manifest. So, rather than nit-pick here, we’ll call those two things a wash and go with 125ppm/ºC as a reasonable value as determined from observations.
We can also try to determine it from models.
Climate models run with only CO2 increases produce about 1.8C of warming at the time of a doubling of the atmospheric carbon dioxide concentrations. A doubling is usually taken to be a change of about 280ppm. So, we have 280ppm divided by 1.8ºC equals 156ppm/ºC. But, the warming is not fully realized by the time of doubling, and the models go on to produce a total warming of about 3ºC for the same 280ppm rise. This gives us, 280ppm divided by 3ºC which equals 93ppm/ºC. The degree to which the models have things exactly right is highly debatable, but close to the middle of all of this is that 125ppm/ºC number again—the same that we get from observations.
So both observations and models give us a similar number, within a range of loose assumptions.
Now we have what we need. It takes ~14,138mmt of CO2 emissions to raise the atmospheric CO2 concentration by ~1 ppm and it takes ~125 ppm to raise the global temperature ~1ºC. So multiplying ~14,138mmt/pmm by ~125ppm/ºC gives us ~1,767,250mmt/ºC.
That’s our magic number—1,767,250.
Write that number down on a piece of paper and put it in your wallet or post it on your computer.
This is a handy-dandy and powerful piece of information to have, because now, whenever you are presented with an emissions savings that some action to save the planet from global warming is supposed to produce, you can actually see how much of a difference it will really make. Just take the emissions savings (in units of mmt of CO2) and divide it by 1,767,250.
Just for fun, let’s see what we get when we apply this to a few save-the-world suggestions.
According to NativeEnergy.com (in association with Al Gore’s ClimateCrisis.net), if you stopped driving your average mid-sized car for a year, you’d save about 5.5 metric tons (or 0.0000055 million metric tons, mmt) of CO2 emissions per year. Divide 0.0000055mmtCO2 by 1,767,250 mmt/ºC and you get a number too small to display on my 8-digit calculator (OK, Excel tells me the answer is 0.00000000000311ºC). And, if you send in $84, NativeEnergy will invest in wind and methane power to offset that amount in case you actually don’t want to give up your car for the year. We’ll let you decide if you think that is worth it.
How about something bigger like not only giving up your mid-sized car, but also your SUV and everything else your typical household does that results in carbon dioxide emissions from fossil fuels. Again, according to NativeEnvergy.com, that would save about 24 metric tons of CO2 (or 0.000024 mmt) per year. Dividing this emissions savings by our handy-dandy converter yields 0.0000000000136ºC/yr. If you lack the fortitude to actually make these sacrifices to prevent one hundred billionth of a degree of warming, for $364 each year, NativeEnergy.com will offset your guilt.
And finally, looking at the Waxman-Markey Climate Bill that is now being considered by Congress, CO2 emissions from the U.S. in the year 2050 are proposed to be 83% less than they were in 2005. In 2005, U.S. emissions were about 6,000 mmt, so 83% below that would be 1,020mmt or a reduction of 4,980mmtCO2. 4,980 divided by 1,767,250 = 0.0028ºC per year. In other words, even if the entire United States reduced its carbon dioxide emissions by 83% below current levels, it would only amount to a reduction of global warming of less than three-thousandths of a ºC per year. A number that is scientifically meaningless.
This is the type of information that we should be provide with. And, as we have seen here, it is not that difficult to come by.
The fact that we aren’t routinely presented with this data, leads to the inescapable conclusion that it is purposefully being withheld. None of the climate do-gooders want to you know that what they are suggesting/demanding will do no good at all (at least as far as global warming is concerned).
So, if you really want to, dust off your bicycle, change out an incandescent bulb with a compact fluorescent, or support legislation that will raise your energy bill. Just realize that you will be doing so for reasons other than saving the planet. It is a shame that you have to hear that from us, rather than directly from the folks urging you on (under false pretenses).
