Converging evidence on climate change

Posted on January 31, 2011 | 13 Comments

This graph thanks to Skeptical Science (Ten temperature records in a single graphic). As the web site says this graph of ten different temperature records provides “a vivid reminder that many independent lines of evidence all tell us the same thing.”

Pretty well underlines the fact that global temperature are rising. The Intergovernmental Panel on Climate Change (IPCC) describes this conclusion as unequivocal.

As for the cause – it’s worth recalling these figures from the last IPCC repport (I discussed these in Climate change is complex).

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.

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13 responses to “Converging evidence on climate change”

  1. poneke | January 31, 2011 at 12:49 pm |

    The world has been warming since the end of the Little Ice Age. That is incontrovertible.

    Like

  2. Ken | January 31, 2011 at 12:57 pm |

    Poneke, your statement is similar to the IPPCC statement that evidence for the increase in global temperatures is unequivocal.

    So what is your comment on the other two graphs?

    Like

  3. drewski | January 31, 2011 at 8:25 pm |

    We need scientists to take up the gauntlet and begin speaking forcefully in support of their studies. PR and denialist spin doctors have stolen the limelight and the REAL scienyists need to take it back with as much media coverage as possible.

    Like

  4. Cedric Katesby | January 31, 2011 at 9:22 pm |

    The world has been warming since the end of the Little Ice Age. That is incontrovertible.

    The big bag of stupid opens up.
    The zombie PRATT’s that will never die.
    Follow the science.

    Like

  5. max | February 1, 2011 at 6:30 am |

    “The big bag of stupid opens up.”

    And Cedric announces his entry into the room 😉
    (joke Cedric…. its OK!)

    Like

  6. Andrew W | February 1, 2011 at 7:50 pm |

    So Poneke has changed his position from “there’s no REAL warming” to “it’s warming, but it’s natural”. That little baby step only took a couple of years.

    Like

  7. poneke | February 2, 2011 at 11:08 am |

    I haven’t changed my position at all, Mr Worth. The world has been warming since the Little Ice Age. That is an incontrovertible fact. Ken’s graphs show it… graphically.

    Like

  8. Richard Christie | February 2, 2011 at 11:22 am |

    So, Mr McLoughlin, still no warming since 1998?
    You’ve shouted that one often enough.
    Tell us, what can we infer from that?

    Like

  9. Ken | February 2, 2011 at 11:44 am |

    Poneke, what the graphs show is that there has been significant warming this century and the warming in the last 50 years cannot be explained purely by natural causes (as the previous warming can).

    Only when human inputs are included can we explain that increase.

    Significantly you refuse to comment on that.

    Like

  10. david winter | February 2, 2011 at 1:04 pm |

    Hey Poneke,

    How? I’ve no desire to get into a shouting match, but people who say the world has warmed since the LIA very seldom explain why that would happen . Climate is not on an elastic band, it doesn’t get warmer simply because it was cooler before, so something has to drive that warming. What is it? Why has it accelerate recently?

    Like

  11. Gabriel B. Atega | June 8, 2011 at 2:08 pm |

    Which human activity?

    Personally, I believe it is deforestation, and not CO2 emissions. Why is it that scientists are not studying or publishing the aggregate impact of deforestation that peaked in the second half of the 1800’s and continued to reduce global forests even today? How much CO2 absorption capacity has been lost? How much water vapor have been released to the atmosphere from the lost of the forests?

    Like

  12. Cedric Katesby | June 8, 2011 at 7:05 pm |

    Personally, I believe it is deforestation, and not CO2 emissions.

    That’s nice.

    Why is it that scientists are not studying or publishing…

    Don’t waste time on the internet. You may have just discovered something that NASA and the NAS and the Royal Society and all the other scientific communities on the planet have not thought of before!
    Maybe.
    Or maybe not.
    Get out there and publish a paper in the peer-reviewed literature and claim that Nobel Prize. Don’t let them keep you silent.
    Yet before you do, you might want to do a bit of background research on what scientists have already done.
    Take a lecture or two…

    The American Denial of Global Warming

    Fame and fortune awaits.

    Like

  13. Ken | June 8, 2011 at 7:21 pm |

    Gabriel, look through the most recent IPCC report – I am sure you will find references to the work done in this area. I can certainly remember references to such work . It’s just not true to claim that this is not being researched.

    Like

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