The Foundational Case for Global Warming

Despite what seems to be an ironclad case for global warming and the assumption that it is human caused , there is still considerable debate in the media. If we are going to create appropriate public policy to deal with climate change, then we have to keep from being diverted by the fallacious arguments. Unfortunately, there is a lot of phooey out there perpetuated by people who cite scientists and who claim to be scientists. I’m not sure if these people are just misinformed or working on behalf of a hidden agenda, but we can filter them out by keeping aware of the essential situation.

The fundamental proposition goes like this:

1. For about the last 100 years, the Co2 level has been rising at an unprecedented rate. According to the Woods Hole Research Center,

Suddenly in the 1800s, as the Industrial Revolution takes off, atmospheric CO2 concentrations begin an unprecedented upward climb, rising rapidly from 280 ppmv (parts per million by volume) in the early 1800s to a current level of 376 ppmv, 77 ppmv above the highest concentrations previously attained in the course of the preceding 400 thousand years.

Global Temperature

Global Temperature

2. The rise in atmospheric CO2 seems to correspond to–and likely be causing–rapidly rising global temperatures, as show in the graph at right from NASA. The graph shows temperature anomalies relative to the mean temperature of the years 1951 to 1980.

Debate about the temperature rise concerns how the temperature is measured. There is no one thermometer for the planet, so a single temperature is computed by taking measurements from various points around the globe or from satellites. Experts dispute the appropriate ways to do this; however, the general conclusion seems to be that the temperature is rising abnormally.

3. Suspicions are high that the phenomena has been a side effect of industrialization. According to the Washington Post,

An international panel of climate scientists said yesterday that there is an overwhelming probability that human activities are warming the planet at a dangerous rate, with consequences that could soon take decades or centuries to reverse.

Any argument against global warming would have to directly refute this data. We are faced with many pressing social issues, and they can become hopelessly complex unless we have some grounding in the data and use a combination of data and commonsense to weed out spurious arguments. In future posts, I’ll take a look at some of the counterarguments and see if any can overturn this.


  1. adam nedman on October 22, 2008 at 2:44 am

    Nice website. ^_^ Sorry about the long comment – actually, I left out a lot of other stuff because they’re too tangential.

    Anyhoo, I’m a fence sitter on global warming. I’d like to wait about 5 years more before committing based upon the temperature data. This is the reasoning / junk that is going through my head after reading this and that on anthropogenic global warming (AGW) theory.

    1) People waste time taking the dumbest arguments and people on both sides to score easy points. Take the strongest arguments and the smartest people from both sides. I believe that both sides have respected climate researchers who believe that they are right, but just have differing interpretations of the data.

    2) I think the main pillars of the AGW arguments are based upon two things – 1) the climate models and 2) the lack of an alternative hypothesis. Essentially, the AGW propopents say that there is nothing other than CO2 that could explain the rise. Until the skeptics can come up with a strongly supported, alternative cause / mechanism, the skeptics are in a tough spot. However, the skeptics are right in pointing out that the climate models have serious deficiencies and unknowns such as how to model effects of clouds.

    3) I read a while back that Vostok ice core data was conclusive proof of CO2-AGW link and was excited. Then I saw in the graph that CO2 lagged temperature change and wondered what was going on. Subsequent papers showed that the lag was real and roughly 800 yrs. This doesn’t debunk AGW since an unknown factor could cause initial temp rise, then CO2 positive feedback kicks in, and the lag could be due to oceans releasing CO2, etc. OTOH, the Vostok ice core data doesn’t debunk weak CO2 feedback either, where CO2 mostly follows temp.

    CO2 is a weak greenhouse gas. CO2 warming theory only works because of estimates about the water vapor feedback effect and its persistence in atmosphere that make the overall effect of CO2 stronger. If the estimates are off, then it could be that CO2 isn’t as strong as claimed.

    4) When I first eyeballed the global temp data I saw a simple pattern. 1880-1920 flat, 1920-1940 spike, 1940-1980 flat, 1980-2000 spike. My guess was that 2000-2040 should be flat. That pattern has been holding up. Man-made global warming may not be as extreme as people have claimed based upon the temp spike during 80’s-90’s. Warming might still be anthropogenic, but only around 0.7C/100yrs or so … which is much less than most of the climate model predictions.

    5) The flat region 1940-1980 needed explanation and so the aerosol / global dimming theory was kinda kludged on to make it work. I’m not so sure about it after seeing some graphs, kinda ugly looking fit, but I don’t know enough about it. Maybe it’s just part of a natural weather oscillation?

    6) I’ve bumped into people who go into environmental research. They’re not exactly unbiased. That is not to say that they can’t do good science, but … heh.

    7) Decrease in Arctic ice might be due to shift in weather patterns (jet stream?) instead of global climate change. Can’t have your cake and eat it too. Can’t claim that anything that supports AGW is evidence of long-term climate change, but then dismiss anything that contradicts it as just short-term weather phenomena.

    8) Rate of change is more important than the absolute number. The rate of change has slowed over the past 10 years. Is this short-term weather masking underlying long-term climate change? Or do AGW theories need to be revised? Interesting …

    So essentially, my PoV is that if temp stays relatively flat for 5 more years, AGW theories may have a problem and will have to be revised to at least include natural weather oscillations, reassess the aerosol dimming theory, etc. I believe that waiting a few more years isn’t too unreasonable, although the counterargument is the “tipping point” argument, i.e. we can’t wait 5 years because by then our climate will be irretrievably damaged. I’ve heard this argument used with Arctic sea ice. However, this year, Arctic sea ice did better than last year’s minimum, so we haven’t reached that tipping point yet.

    Of course, I could be wrong. Dunno. Hope my reasoning isn’t too irrational, heh. %^)

  2. Doug on October 22, 2008 at 9:37 am

    Adam, thanks for taking the time to make such a nice set of well thought out statements that stick to the point. You’re not irrational at all, and I think make some good points about where the global warming argument needs to be expanded and explored further.

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