Climate change is complex

Posted on August 11, 2010 | 8 Comments

I am always amazed at the way climate change sceptics, contrarians and deniers appear to think climatology is simple. They will latch on to one thing and claim it explains everything. They are the ultimate reductionists.

So, no! Climate is not influenced by greenhouse gases. The observed global temperatures can be “explained” by clouds. Or by cosmic rays, sunspots, volcanoes, El Nino, etc., etc.

On the other hand they will claim that climate scientists and the Intergovernmental Panel on Climate Change (IPCC) are ignoring natural influences. That they are considering only human caused effects.

Of course climate scientists are not that stupid. They are experts in the field, recognise the climate system is complex and attempt to consider all the relevant effects – natural and human caused.

Natural influences just can’t explain global temperature

You only have to look at the IPCC reports to see this. For example the figure below shows the results of simulations of global temperature from 1900 to 2005. Figure a included all the natural and anthropogenic influences.  The black line is the actual measured global temperature anomaly (obtained by subtracting the average temperature for 1901 to 1950).  The individual simulations are shown as thin yellow curves. The red line is the multi-model ensemble mean (see Figure 9.5 – AR4 WGI Chapter 9: Understanding and Attributing Climate Change).

Figure b is a similar plot using simulations which consider only the natural influences on climate. The individual simulations are shown as thin blue curves. The thick blue line is the multi-model ensemble mean.

So, climate scientist have considered both natural and anthropogenic influences. And they are unable to reproduce the global temperature changes since 1970 unless anthropogenic influences are included.

That is why the IPCC has concluded that there is a high probability (>90%) that human influences are contributing to the current observed global temperature increase.

Notice also that the experts talk about probabilities. It’s a complex field and things are rarely cut and dried. We are more certain about some influences than others. And the IPCC doesn’t hide this fact – far from it. It doesn’t make sweeping claims in the way that some of their opponents do.

Knowing what we don’t know

We can see this in another figure from the report (Figure 2.20 – AR4 WGI Chapter 2: Changes in Atmospheric Constituents and in Radiative Forcing). It shows the estimated influences of several human caused effect and solar radiation since 1750. Notice the error bars. They are much bigger in some cases than others. Notice the assessment of scientific understanding for these influences. We have a high understanding for some of them and a low understanding for others.

So, climate scientists aren’t hiding anything. They are not ignoring natural effects. They are up-front about probabilities. They acknowledge that we need more information is some areas. They are behaving like professionals.

Considering there are areas where scientific understanding is low there is clearly room for debate, discussion and more research. But deniers and contrarians who take an extreme reductionist stance, misrepresent the IPCC reports and attack honest scientists doing the research are not in a position to contribute to this.

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8 responses to “Climate change is complex”

  1. Mekhong Kurt | August 11, 2010 at 6:35 pm |

    You’re preaching to the choir, in my case.

    About a year ago, I got involved in an online comments section with a denier, but he actually came across as intelligent and willing to examine alternative possibilities. He gave me what I thought was a friendly challenge to put together some data, a rather daunting task, considering that I’m not a scientist. (I am, however, educated to master’s level in the humanities, and taught many years in universities, two in America and several in Asia, so neither am I without a grasp of the scientific method and traditional logic.)

    I spent about two weeks and somewhere in the range of 60-80 hours (wish I had kept a log) assimilating online sources from all over the world, being careful to choose both public and private ones, as well as a variety of types of sources — government agencies, parallel private ones (such as private weather services), dedicated research institutes, universities generally, and individual private investigators.

    I had several dozen links at the end, and I added a brief description of what each addressed.

    I also added a follow-on section of historical records drawn from many sources, ranging from weather stations over time to newspaper accounts.

    All set, I sent a message via the comments section that I had the stuff ready, and he told me to print away, which I did.

    Next time I checked, I had a very curt response. I can’t quote it exactly, but it was along these lines: “I don’t have time to wade through so many links. Besides, I’m certain they’re all socialist-Al Gore lies.”

    I guess I should have known better. But for a few moments, I was truly enraged (stupid in itself, I know).

    I have found a way to engage deniers, sometimes, and skeptics, most of the time. I point out that even if climate change *is* nothing more than an Al Gore lie designed to enrich him and his cohorts, we can all agree, for instance, that many places suffer from smog, which not only fouls the air, water, and soil, nor only dirty buildings, break down paints, etc., but also has health effects — all good reasons themselves, entirely independent of climate change, to address these matters. I also point out that except for the extremely rare wing nut, we all agree that at *some* point, fossil fuels are going to run out, though we may debate just when that will happen, adding that as a reason to address these concerns insofar as they involve fossil fuels. As I already said, even staunch deniers sometimes allow that, and I suspect that others do, those who remain silent, those who are damned if they’re going to admit to anything that might even indirectly lend credence to the notion of climate change. Skeptics pretty much all go along with those propositions.

    Of course, one hope I have is that as they consider those perspectives, they may come around to seeing that it’s almost a dead certainty that climate change, “aided” by humans, is indeed occurring, and at the extremes of probability, could be genuinely disastrous — meaning life-ending, at least as we know it.

    BTW, I’ve just run across your blog looking for information on a scientist, and I really like it. Bookmarked it, too.

    Mekhong Kurt
    An American in Bangkok

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  2. Ken | August 11, 2010 at 7:23 pm |

    Mekhong Kurt, thanks for the comment. I can appreciate your frustration with the sceptic’s unwillingness to consider the information. Unfortunately I think this sort if confirmation bias is very common, particularly on the Internet.

    And the climate change issue seems to bring out the prejudices. In a way it’s a method of coping (avoiding) with an issue which seems so difficult.

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  3. NickS | August 12, 2010 at 9:06 pm |

    @Mekhong Kurt

    That’s never fun, unless you can use it against them in future 😀

    These days though I generally make one or two posts and if I don’t get a response, or the other person can’t understand basic logic, I don’t carry on unless it’s an interesting topic.

    And Ken, thanks for this, I’ll probably end up trying to make use of it in future, as it nicely highlights how the IPCC works out it’s not natural causes behind climate change.

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  4. Fred | August 12, 2010 at 9:59 pm |

    Of course, the astute reader will note the obvious fallacy in the above argument.

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  7. David Thompson | March 4, 2013 at 3:34 pm |

    To a certain extent I disagree with you – climate change is simple. If we look at the simple and inarguable reality that the entire planet is experiencing extreme weather events at an unprecedented level and at the same time the average temperature is increasing. Tens of thousands of experts and scientists; the majority of whom have no contact with each other, all say pretty much the same thing, that the primary cause is the billions of tonnes of carbon we have put in the atmosphere.

    So here’s the situation:
    1. There are no other, even remotely probable, causes for the planet warming up than the atmosphere becoming more effective at containing heat
    2. If it is a scam of unprecedented scale, then tens of thousands of people from all over the world are all faultlessly keeping a very complex secret. None of them have got drunk and blurted out the truth, none of them have been hit by an attack of guilts and none of them have accidentally left their files accessible and none of the “think tanks” have busted their cunning secrets. The reward for doing that would be huge, so if it were possible someone would have done it by now.
    3. If the scientists are making stuff up to get funding, then publishing the paper that revealed the “truth” would make the author(s) instantly scientific superstars and guarantee a seat at the very best universities on the planet with huge salaries, private jets and a fleet of Hummers to drive around in.

    So to me the answer is simple: less of the energy entering the atmosphere is escaping because the atmosphere has a different chemical composition than it did 100 years ago. That’s why the climate is changing.

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  8. Pingback: Climate change is not simple | Secular News Daily

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