Roy Spencer's paper on climate sensitivity
What the science says...
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|Spencer's model is too simple, excluding important factors like ocean dynamics and treats cloud feedbacks as forcings.|
Climate scientists have identified a number of fundamental problems in Spencer and Braswell's 2011 study which wrongly concludes that the climate is not sensitive to human greenhouse gas emissions. One of the main problems with the paper is that it uses Roy Spencer's very simple climate model which we've previously looked at in .
This simple model does not have a realistic representation of the Earth's oceans, which are a key factor in the planet's climate, and it also doesn't model the Earth's water cycle. One key aspect in the Earth's temperature changes is the El Niño Southern Oscillation (ENSO), which is a cycle of the Pacific Ocean. Spencer's model does not include ENSO, and he assumes that ENSO responds to changes in cloud cover, when in reality it's the other way around.
There are some other key problems in the paper. It doesn't provide enough information for other scientists to repeat the study. When two other climate scientists (Kevin Trenberth and John Fasullo) tried to replicate its results as best they could with the information provided, they found quite different results (see the Advanced version of this rebuttal for further details). Spencer and Braswell's conclusions also only seems to work using the satellite data set they chose, but Trenberth and Fasullo found that using other data sets also changes their results.
Trenberth and Fasullo also found that when using a few different climate models, the one which replicated the observed data best was the one with a climate more sensitive to greenhouse gases, which directly contradicts Spencer and Braswell's conclusion that the climate is not sensitive to greenhouse gases.
It's also worth noting that the journal which published Spencer and Braswell's paper does not normally publish climate science research. This may explain how the paper made it through their peer-review system with so many problems. In the end, Trenberth and Fasullo find that the Spencer and Braswell study has no merit.
- The model it uses is far too simple to accurately represent the Earth's climate
- The paper doesn't provide enough information to replicate their results
- Their results depend on using one particular data set
- They assume that ENSO responds to cloud cover changes, when in reality, the reverse is true
- The study's conclusions are incorrect and unsupportable
UPDATE 3 Sep 2011: Wolfgang Wagner, has stepped down as editor-in-chief of the journal Remote Sensing. Wagner concluded the Spencer's paper was "fundamentally flawed and therefore wrongly accepted by the journal". More here...
Last updated on 1 August 2011 by dana1981.