Explain the data with possibly ten different reasons or just one

10 Indicators of a Human Fingerprint on Climate Change
[Via Skeptical Science]

The NOAA State of the Climate 2009 report is an excellent summary of the many lines of evidence that global warming is happening. Acknowledging the fact that the planet is warming leads to the all important question – what’s causing global warming? To answer this, here is a summary of the empirical evidence that answer this question. Many different observations find a distinct human fingerprint on climate change:

10 Indicators of a Human Fingerprint on Climate Change

To get a closer look, click on the pic above to get a high-rez 1024×768 version (you’re all welcome to use this graphic in your Powerpoint presentations). Or to dig even deeper, here’s more info on each indicator (including links to the original data or peer-reviewed research):

  1. Humans are currently emitting around 30 billion tonnes of CO2 into the atmosphere (CDIAC). Of course, it could be coincidence that CO2 levels are rising so sharply at the same time so let’s look at more evidence that we’re responsible for the rise in CO2 levels.
  2. When we measure the type of carbon accumulating in the atmosphere, we observe more of the type of carbon that comes from fossil fuels (Manning 2006).
  3. This is corroborated by measurements of oxygen in the atmosphere. Oxygen levels are falling in line with the amount of carbon dioxide rising, just as you’d expect from fossil fuel burning which takes oxygen out of the air to create carbon dioxide (Manning 2006).
  4. Further independent evidence that humans are raising CO2 levels comes from measurements of carbon found in coral records going back several centuries. These find a recent sharp rise in the type of carbon that comes from fossil fuels (Pelejero 2005).
  5. So we know humans are raising CO2 levels. What’s the effect? Satellites measure less heat escaping out to space, at the particular wavelengths that CO2 absorbs heat, thus finding “direct experimental evidence for a significant increase in the Earth’s greenhouse effect”. (Harries 2001, Griggs 2004, Chen 2007).
  6. If less heat is escaping to space, where is it going? Back to the Earth’s surface. Surface measurements confirm this, observing more downward infrared radiation (Philipona 2004, Wang 2009). A closer look at the downward radiation finds more heat returning at CO2 wavelengths, leading to the conclusion that “this experimental data should effectively end the argument by skeptics that no experimental evidence exists for the connection between greenhouse gas increases in the atmosphere and global warming.” (Evans 2006).
  7. If an increased greenhouse effect is causing global warming, we should see certain patterns in the warming. For example, the planet should warm faster at night than during the day. This is indeed being observed (Braganza 2004, Alexander 2006).
  8. Another distinctive pattern of greenhouse warming is cooling in the upper atmosphere, otherwise known as the stratosphere. This is exactly what’s happening (Jones 2003).
  9. With the lower atmosphere (the troposphere) warming and the upper atmosphere (the stratophere) cooling, another consequence is the boundary between the troposphere and stratophere, otherwise known as the tropopause, should rise as a consequence of greenhouse warming. This has been observed (Santer 2003).
  10. An even higher layer of the atmosphere, the ionosphere, is expected to cool and contract in response to greenhouse warming. This has been observed by satellites (Laštovi?ka 2006).

Science isn’t a house of cards, ready to topple if you remove one line of evidence. Instead, it’s like a jigsaw puzzle. As the body of evidence builds, we get a clearer picture of what’s driving our climate. We now have many lines of evidence all pointing to a single, consistent answer – the main driver of global warming is rising carbon dioxide levels from our fossil fuel burning.


Numbers 1, 2 and 5 were the ones to really convince me that humans were the ones involved. The additional 7 all bolstered the human fingerprint on climate change. There are also more than just 10 but these are the easiest to discuss.

Many denialists will have to come up with multiple theories – perhaps 10 – to explain all these data, data that can be explained by scientists with one theory. As Feynman said:

The first principle is that you must not fool yourself–and you are the easiest person to fool. So you have to be very careful about that. After you’ve not fooled yourself, it’s easy not to fool other scientists.

The denialists continue to construct a Cargo Cult World yet here are 10 easy bits of data for them to deal with. Perhaps they can build something that will actually fly.

The best proposal that fits all the data is that human actions result in the warming of the earth.. Our continuing inactions will simply not help matters at all.

4 thoughts on “Explain the data with possibly ten different reasons or just one

  1. See previous post. I have done all I can as an individual. Now work on China, India, etc. Particularly China. They have been riding bikes and walking for centuries and have done just fine. Why encourage them to build and use cars when you are trying to make us stop?

    1. There is a lot that can be done. The first step is mitigating the carbon production curve we are on, to try an stop the ever increasing production of GHG. The Stabilization Wedges area good start. I also mentioned in an earlier post a McKinsey report that discussed carbon abatements. It provides an idea of the costs from different abatements for greenhouse gas emissions. Pushing for better fuel efficiencies in commercial vehicles and in office buildings could have a huge effect and actually save large amounts of money.It would actually make our industries more efficient that others and lower business costs.

      But it requires political will to get these changes enshrined, especially at the local level. Changing building codes will be required, as a start.

  2. But you haven’t told me what more I am suppose to do and, yet, the conservationists are blaming me for not conserving. No one ever gives us (the “small” people) credit for what we have already done—change lightbulbs, don’t drive as much, etc—all they want us to do is MORE. Like what?
    Judging from what I am reading lately, all I have to do is sit back and let the EPA make rules to run my life. And hand over wads of cash. None of their rules are cheap!

  3. As shown by several different approaches, some of which I listed above, there are things that can be done that actually save us all money as well as reduce carbon emissions.

    Trying to make sure these low hanging fruit are implemented would be a great start.

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