Global Warming
Maybe it shouldn't surprise me that there are still people that doubt the effect that human activity is having on the atmosphere and the global mean temperature as a result, but it does. One of my colleagues remarked about a snow storm last year, "So! Do you still believe in global warming?" Her argument was just silly, if there were blizzards all over the planet at the same time, maybe not, but snow in Ohio in December is not evidence contrary to global warming. There is not only plenty of evidence for the presence of Anthropogenic (man created) warming but the facts are actually pretty simple once one settles on which data are reliable.
Reasonable people can agree that carbon dioxide (CO2) is a greenhouse gas. "Carbon dioxide, ... causes between 9-26% [of the greenhouse effect on Earth]. http://en.wikipedia.org/wiki/Greenhouse_gas.
Further, no one should doubt that the atmospheric CO2 levels are rising and have been for decades. The amount of CO2 in the atmosphere has risen from about 280 parts per million in 1800 to 380 parts per million today. http://www.sciam.com/article.cfm?articleID=000A751A-F39F-10F6-B39F83414B7F0000.
Two of the largest CO2 emission sources include volcanic and anthropogenic. Volcanic activity now releases about 130 to 230 teragrams (145 million to 255 million short tons) of carbon dioxide each year. http://en.wikipedia.org/wiki/Volcanic#Gas_emissions. Another source, Gerlach, estimated a total global release of 3-4 x 10E12 mol/yr from volcanoes. http://volcano.und.edu/vwdocs/Gases/man.html. At 44.01 g/mol, this estimate yields an expected output of 132-176 teragrams annually.
On the other hand, anthropogenic source estimates are much higher. From 1850 to 2000, 282 PgC were released by combustion of fossil fuels. http://cdiac.esd.ornl.gov/pns/faq.html. Note that is 1880 teragrams per year and does NOT include the oxygen components of the CO2 and thus is a VERY conservative estimate. This is also conservative because it only includes fossil fuel consumption and not cement production (a large contributor) or other man-made sources. Even so, this estimate is an order of magnitude greater than volcanic sources combined. Another estimate comes from the National Energy Information Center. http://www.eia.doe.gov/emeu/aer/txt/ptb1119.html. They estimate a total annual output of CO2, from energy consumption alone, as larger than 22,000 million metric tons. Since a metric ton is a megagram, this is equivalent to 22 million gigagrams or 22,000 teragrams of CO2 annually!! This is TWO orders of magnitude greater than volcanic sources combined.
So, since human and volcanic sources are the greatest emitters and since human sources are at least one order of magnitude larger, human are the single largest source of CO2 emissions. This should come as no surprise: human fossil fuel consumption actually makes CO2. All volcanoes do is release stored CO2 dissolved in the molten rock. There is no such thing a coal-powered volcano… If you've been listening to some clown on the radio telling you something like "one volcanic eruption releases more CO2 than all human sources combined over decades", then you were lied to. Reconsider your sources.
Reasonable people know that CO2 is a greenhouse gas, that rising levels will increase trapped heat on Earth, that trapped heat increases global temperature, and that CO2 levels are rising. As such, it should come as no surprise to anyone that Earth is warming on a global level. The next question is, what is the cause of rising CO2 levels, since Anthropogenic sources are the largest contribution to CO2 emissions, it follows that humans are causing the rise, and, consequently, that we are causing global warming.
We need to get our collective heads out of our collective rears and take responsibility for the results of our actions. If the Earth warms, climate changes. CO2 is the largest single human-controllable variable in the global warming equation. Since we are not prepared for the disruption caused by climate change, we need to work to slow (or stop) our CO2 output and reverse the damage we are doing.
Reasonable people can agree that carbon dioxide (CO2) is a greenhouse gas. "Carbon dioxide, ... causes between 9-26% [of the greenhouse effect on Earth]. http://en.wikipedia.org/wiki/Greenhouse_gas.
Further, no one should doubt that the atmospheric CO2 levels are rising and have been for decades. The amount of CO2 in the atmosphere has risen from about 280 parts per million in 1800 to 380 parts per million today. http://www.sciam.com/article.cfm?articleID=000A751A-F39F-10F6-B39F83414B7F0000.
Two of the largest CO2 emission sources include volcanic and anthropogenic. Volcanic activity now releases about 130 to 230 teragrams (145 million to 255 million short tons) of carbon dioxide each year. http://en.wikipedia.org/wiki/Volcanic#Gas_emissions. Another source, Gerlach, estimated a total global release of 3-4 x 10E12 mol/yr from volcanoes. http://volcano.und.edu/vwdocs/Gases/man.html. At 44.01 g/mol, this estimate yields an expected output of 132-176 teragrams annually.
On the other hand, anthropogenic source estimates are much higher. From 1850 to 2000, 282 PgC were released by combustion of fossil fuels. http://cdiac.esd.ornl.gov/pns/faq.html. Note that is 1880 teragrams per year and does NOT include the oxygen components of the CO2 and thus is a VERY conservative estimate. This is also conservative because it only includes fossil fuel consumption and not cement production (a large contributor) or other man-made sources. Even so, this estimate is an order of magnitude greater than volcanic sources combined. Another estimate comes from the National Energy Information Center. http://www.eia.doe.gov/emeu/aer/txt/ptb1119.html. They estimate a total annual output of CO2, from energy consumption alone, as larger than 22,000 million metric tons. Since a metric ton is a megagram, this is equivalent to 22 million gigagrams or 22,000 teragrams of CO2 annually!! This is TWO orders of magnitude greater than volcanic sources combined.
So, since human and volcanic sources are the greatest emitters and since human sources are at least one order of magnitude larger, human are the single largest source of CO2 emissions. This should come as no surprise: human fossil fuel consumption actually makes CO2. All volcanoes do is release stored CO2 dissolved in the molten rock. There is no such thing a coal-powered volcano… If you've been listening to some clown on the radio telling you something like "one volcanic eruption releases more CO2 than all human sources combined over decades", then you were lied to. Reconsider your sources.
Reasonable people know that CO2 is a greenhouse gas, that rising levels will increase trapped heat on Earth, that trapped heat increases global temperature, and that CO2 levels are rising. As such, it should come as no surprise to anyone that Earth is warming on a global level. The next question is, what is the cause of rising CO2 levels, since Anthropogenic sources are the largest contribution to CO2 emissions, it follows that humans are causing the rise, and, consequently, that we are causing global warming.
We need to get our collective heads out of our collective rears and take responsibility for the results of our actions. If the Earth warms, climate changes. CO2 is the largest single human-controllable variable in the global warming equation. Since we are not prepared for the disruption caused by climate change, we need to work to slow (or stop) our CO2 output and reverse the damage we are doing.
posted by Minotaur at 9:57 AM
4 Comments:
Sorry... I don't buy it! “Predictions of global warming are based on computer climate modeling, a branch of science still in its infancy. The empirical evidence actual measurements of Earth's temperature shows no man-made warming trend. Indeed, over the past two decades, when CO2 levels have been at their highest, global average temperatures have actually cooled slightly.“ http://sitewave.net/pproject/s33p36.htm
Sure CO2 levels are increasing at this time. But for the last 300 years or so, they have been lower than usual and are increasing with the general warming trend since "The Little Ice Age". Human activity may certainly be adding to the CO2 increase, but there is also no actual evidence that this increase is causing any “warming effect”. In fact, recent carbon dioxide rises have shown a tendency to follow rather than lead global temperature increases.
Sorry... I don't buy it! “Predictions of global warming are based on computer climate modeling, a branch of science still in its infancy. The empirical evidence actual measurements of Earth's temperature shows no man-made warming trend. Indeed, over the past two decades, when CO2 levels have been at their highest, global average temperatures have actually cooled slightly.“ http://sitewave.net/pproject/s33p36.htm
Sure CO2 levels are increasing at this time. But for the last 300 years or so, they have been lower than usual and are increasing with the general warming trend since "The Little Ice Age". Human activity may certainly be adding to the CO2 increase, but there is also no actual evidence that this increase is causing any “warming effect”. In fact, recent carbon dioxide rises have shown a tendency to follow rather than lead global temperature increases.
Sometimes it appears that everybody in America (perhaps that should read “the western world”) lives in a constant state of fear. During much of the first half of the last century the fear was eugenics, and later it was the Soviet Union. When Ronald Reagan won the Cold War, there was suddenly a “fear vacuum” in the west. What do we do now to get the adrenaline flowing and keep ourselves at the cutting edge? Almost immediately, the fear-mongers stepped in with global warming to fill the gap. What all these conflicting studies and opinions about global warming really convey is how little we actually know about the Earth’s climate and how it works. Until we better understand that, we have no idea what the effect of mankind’s activity is having on the planet or whether it is for better or worse. Seems like a little global warming might be a good thing. Who knows?
It seems that you are comparing global warming with fear mongering. I think that idea is dismissive: it assumes that the concept is alarmist and, by extension, without merit. As with any potential risk, it is worthwhile to evaluate it in order to calculate the best course of action. In order to do so, we must assume a priori that the risk is legitimate. As such, I consider the assumption that it is "fear mongering" to be premature at best.
Regarding your observation of the existence of "conflicting studies and opinions", I would counter that there isn't really that much credible controversy any longer: the "reports" and "web sites" showing that global warming doesn't exist are full of poor science and should not be credited. It is also observable that CO2 levels in the atmosphere are rising and we should expect warming as a result. That the globe is warming is also observable. See my post "Global Warming II" for sites documenting global ice retreat trends for examples or look at Angell's data on atmospheric temperature records or check out the ACIA data at http://www.ucsusa.org/global_warming/science/arctic-climate-impact-assessment.html.
Regarding your observation that the future effects of mankind's activity are unknown right now, I agree wholeheartedly. However, that is not a reason for complacency, it is a reason for action: we should stand up when someone does something with unknown effects to something we care about. You suggest that a little global warming "might be a good thing". I say that we had better be whole lot more sure than that if we are going to tamper with a system of this scale and import. If mankind is actually warming the earth without knowing the impact, it is irresponsible at best. Since we are the largest source of CO2 emissions as shown in my post "Global Warming", we have enormous control over the its increase and the resultant effects. Unless we know what those effects are we should at least be responsible enough to take control of our own emissions.
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