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Climate Change 

January 28, 2007

The Facts of Climate Change

So what is this Climate Change problem all about? This is actually a very difficult question to answer, because the answer is part science, part economics, part politics, and part human nature. In the next few entries I’ll run through some of the basics of the science behind climate change, the things that we understand, and the things that are still uncertain. But first, let’s review some facts:

1. Earth’s climate has been changing very rapidly over the last few decades.
2. This climate change is driven largely by climbing global temperatures.
3. Global temperatures are climbing because of the tremendous increase of greenhouse gas concentrations in the atmosphere over the last 150 years.
4. The rapid increase of greenhouse gas concentrations is, overwhelmingly, the result of increased human industrialization and utilization of carbon-based fossil fuels.

These are solid observations and cannot be disputed on scientific grounds. In the next entry we’ll get a quick primer on the Earth’s climate! In the meantime, you can take a look at Wikipedia’s excellent entry on the topic (Wikipedia:Climate Change), though as with all Wikipedia entries, remember that there are numerous authors and opinions.


Filed under: Climate Change — Peter @ 11:27 am

5 Comments »

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  3. 1. What does “very rapidly” changing climate mean? To what degree compared to what? I have seen line graphs showing more rapid warming and cooling in the past.
    2. What climate change was driven by climbing global temperatures? It got warmer? Wasn’t if about a half a degree in 100 years?
    3. How did you determine that greenhouse gas concentrations in the atmosphere were “tremendous” and that the increase caused temperatures to climb? Recently hasn’t CO2 increased at the same time temperatures have decreased? Has water vapor increased?
    4. How did you determine that “rapid” increase in greenhouse gasses were the result of human industrialization and carbon-based fossil fuels? I thought that human CO2 was only around 5% of the total CO2. Doesn’t animal respiration account for much more of the CO2? And ocean outgassing account for even more?

    Comment by Don — December 4, 2008 @ 2:23 pm

  4. Answers to Don’s questions –

    1. “Very rapidly” means two things here. First, relative over the time interval for which we have instrument measures (“thermometers”), which extends only a couple of centuries. Over that time, average global temperature has shown a roughly exponential increase beginning approximately 150 years ago. And exactly which line graphs have you seen that relate to the past? I’m sorry, but they don’t exist. This is my area of specialization Don. If you _think_ that you have seen line graphs with steeper slopes, the first thing that you have to do is to equalize the timescales (x-axis). The graphs, or more properly curves, of paleotemperatures which we do have that are comparable to our modern measurements depict measures taken on timescales with significantly lower temporal (time) resolution. So in order to make them comparable to our reconstruction of temperature for the past say 1,000 or 2,000 years, you have to stretch out those curves. And when you do, the slopes become much shallower. Shallower than what we are witnessing today.

    2. Lot’s of climate change is most likely underway as a consequence of the global warming. And yes, it’s gotten warmer; that’s why we call it global warming. And it’s been a bit more than half a degree, Celcius. Don’t you think that’s much? It is! We are talking about average global temperature here, and it takes a HUGE amount of thermal flux to increase or decrease the global temperature. It doesn’t happen easily, and a small temperature change represents a large change in energy.

    3. I didn’t personally make the determination of the greenhouse gas concentrations. Google “Keeling Curve”, and take a look for yourself. And no, carbon dioxide is not increasing as temperature is decreasing. This fallacy is yet more nonsense being promulgated by a skeptical, under-qualified and agenda-driven sector of some sort of media. The Northern Hemisphere is most likely currently entering into a two decade regional cooling based on a long-term northern ocean cycle, and this will imprint itself onto the human-caused warming. But the greenhouse-driven warming will continue, and as this ocean cycle subsides, the warming will make itself felt in a considerable way. Water vapour is tricky. Yes, it seems to be increasing in many regions of the atmosphere (but the global distribution is not even). Any idea why? Warming come to mind?

    4. As for your final question, read the IPCC report. Greenhouse gas increase has been a direct result of our vastly increased utilization of fossil fuels initiated during the Industrial Revolution in the mid-19th century. It doesn’t matter what the percent of human-derived carbon dioxide is. The important factor is how rapidly it is increasing! So what if animal respiration accounts for more? That is actually not changing significantly (and please, if you could come up with a scientifically credible reference for this I would be very interested and grateful). As for ocean outgassing, uhm, no. The oceans are actually carbon dioxide sinks, and absorb carbon dioxide. At this point, however, the absorptive capacity is declining measurably because of the concentration in the ocean. If, or when, the oceans begin to “return” the carbon dioxide, it won’t be as a simple outgassing process, and it will not be pleasant.

    Comment by peter — December 8, 2008 @ 11:43 pm

  5. Hi Jonathan,It can be confusing the nebmur of claims being made that the world is warming / isn’t warming and that’s because the issue has become somewhat divided, often for partisan reasons.No doubt what you’ve been taught in school is correct. If a school were to knowingly misteach it’s pupils then it faces prosecution. Global warming has actually been on trial several times in courts of law and on every occasion the Judge has ruled that the facts and science behind global warming are accurate.Those who don’t accept global warming is happening don’t have an argument against the theory. Instead they have used more than 100 different excuses ranging from claims that the world is cooling, that Margaret Thatcher invented global warming, that it’s because Earth is moving closer to the Sun – all manner of unrelated claims.In your question you mention that you’ve learned that a lot of people are against the idea of global warming. In reality there’s not that many. It’s broadly accepted the world over, the only notable exception being the US where it is more of a political issue than a scientific one.If you look at global warming scientifically then there’s no question that it’s happening. No doubt you were taught that greenhouse gases retain heat in the atmosphere and that the more of them there are the more heat is retained. What you may not have been taught is the mechanism by which these gases retain heat, this is something that is governed by the laws of quantum mechanics.You may think that it would be pointless to try and argue against the theory of gravity, and you’d be right to do so. But it’s even more pointless to argue against the laws of quantum mechanics. Not only are these laws universal and invariable, but they’re the most powerful and successful of all scientific laws. Trying to argue against them really is futile – not that it doesn’t stop some people claiming there’s no such thing as global warming.Because the science is so solid, it’s no surprise then that there isn’t a single scientific organisation on the planet that disputes the theory of manmade global warming.So instead, what we’re left with are a nebmur of uncoordinated, unscientific, and largely uninformed individuals who, often for personal reasons, object to the notion that the world is warming and we, as humans, are having a hand in it.It’s very telling that those who argue against the theory NEVER address the issue as a whole, instead they focus on the minutiae and on the distortion of reality. By adopting this technique it’s possible to ‘disprove’ anything. Take gravity for example, if it existed then trees would grow downwards not upwards, water could never evaporate, birds and planes would crash to the ground, the atmosphere would be sucked down to Earth not up in the sky, Earth would compress itself into a tiny ball etc etc.This is an example of the style of argument used by those who reject the theory of global warming. They latch on to an illogical argument and run with it, steadfastly refusing to acknowledge their own ignorance and basically doing everything they can to avoid exposure to anything that opposes their fallacy.

    Comment by Pangga — March 18, 2012 @ 10:57 am

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