NOT INTERNAL variability

Discussion in 'Environment' started by ScienceRocks, Sep 16, 2011.

  1. ScienceRocks

    ScienceRocks Blue dog all the way!

    Mar 16, 2010
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    Swanson Tsonis variability

    Figure 1: Estimation of the observed signature of internal variability in the observed 20th century global mean temperature in climate model simulations

    As you can see, over periods of a few decades, modeled internal variability does not cause surface temperatures to change by more than 0.3°C, and over longer periods, such as the entire 20th Century, its transient warming and cooling influences tend to average out, and internal variability does not cause long-term temperature trends.

    "The amplitude and time scale of the IMP [internal multidecadal pattern] are such that its contribution to the trend dominates that of the forced component on time scales shorter than 16 yr, implying that the lack of warming trend during the past 10 yr is not statistically significant...While the IMP can contribute significantly to trends for periods of 30 yr or shorter, it cannot account for the 0.8°C warming that has been observed in the twentieth-century spatially averaged SST."

    This conclusion directly contradicts the statement that natural variability can account for all of the recent warming. This is not a new finding, as it is consistent for example with Stouffer et al. (1994):

    "throughout the simulated time series no temperature change as large as 0.5°C per century is sustained for more than a few decades. Assuming that the model is realistic, these results suggest that the observed trend is not a natural feature of the interaction between the atmosphere and oceans."

    and with Wigley and Raper (1990):

    "Simulations with a simple climate model are used to determine the main controls on internally generated low-frequency variability, and show that natural trends of up to 0.3°C may occur over intervals of up to 100 years. Although the magnitude of such trends is unexpectedly large, it is insufficient to explain the observed global warming during the twentieth century"

    ---PEOPLE THIS IS WITH THE TSI FROM THE SUN---You can clearly see how it peaked in 1950 and has been slowly moving downwards with the internal movers.

    It's internal variability
  2. wirebender

    wirebender Senior Member

    Mar 31, 2011
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    Interesting. When I look at the graph I see a change from -0.3 to almost 0.4 between around 1914 to about 1939 and a change from almost 0.4 to -0.2 from 1939 to 1954. Both cases, show a change of more than 0.3.

    Another thing, When I see graphs like this, the first thing I wonder is why the cut off date was 1880 when the temperature record goes considerably further back than that. We have seen numerous examples of warmists attempting to prove thier case with this graph or that graph when it turns out that if they had shown a slightly different time scale, their case would have flown right out the window.

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