“The response of the climate system to rising greenhouse gas levels is often summarized in terms of the equilibrium climate sensitivity (ECS) or the transient climate response (TCR). Both quantities are related to the global mean temperature change ΔT, the radiative forcing change ΔF, and the change in the rate of the total increase in Earth system heat content ΔQ, by the global energy budget:
“(1) ECS = F2x ΔT÷( ΔF- ΔQ)
“(2) TCR = F2x ΔT÷ΔF
“where F2x is the forcing due to doubling atmospheric CO2 concentrations. We use a value of F2x of 3.44 W m?2 (with a 5–95% confidence interval of ±10%) from P M Forster, Journal of Geophysical Research: Atmospheres. Vol 118 1139-1150. Using a higher estimate of 3.7 W m?2 would shift up our estimated ranges for ECS and TCR, but only by about 0.1 K. Both equations (1) and (2) assume constant linear feedbacks and (2) further assumes that the ratio of ΔQ to ΔT for the observed period is the same as that at year 70 of a simulation in which atmospheric CO2 levels increase at 1% per year, which is approximately the case over the past few decades if we exclude periods strongly affected by volcanic. Equation (1) provides a lower bound to the fully equilibrated sensitivity, because delayed ocean warming at high latitudes can mask the impact of local positive feedbacks.”
There are three important points to note:
? This produces a value for equilibrium climate sensitivity BASED ON THE DATA USED of between 1.2°C and 3.9°C. This means the value for ECS is HIGHER than the 1979-2009 estimate that would be obtained using the same methodology.
? These values fall within the range of ECS that is already applied. It is lower than the current upper limit but at the same time it’s higher than the current lower limit. In fact, the article goes on to state that they rule out an ECS of less than 1.2°C, this must be disappointing for the skeptics who claim that enhanced greenhouse gas emissions will have little or no further effect on the climate.
? The assumptions used are that there is a constant liner feedback. You did read that correctly – they used a constant linear feedback, even though no such thing is known in the climate system and they also assumed the ΔQ : ΔT ratio would be the same as that of a 70 year historical simulation. We already know that this isn’t the case which makes one wonder why they would use something that’s known to be wrong.
The assumptions used render any conclusions unreliable, but even if they are correct, it’s nothing new.
The authors are:
? Dr Alexander Otto - Environmental Change Institute, University of Oxford
? Dr Friederike E. L. Otto - Environmental Change Institute, University of Oxford
? Dr Olivier Boucher - Laboratoire de Météorologie Dynamique, IPSL/CNRS, UPMC (l’Université Pierre et Marie Curie )
? Dr John Church - CSIRO Marine and Atmospheric Research Hobart
? Prof Gabi Hegerl - Grant Institute, University of Edinburgh
? Prof Piers M. Forster - School of Earth and Environment, University of Leeds
? Dr Nathan P. Gillett - Canadian Centre for Climate Modelling and Analysis
? Prof Jonathan Gregory - Department of Meteorology, University of Reading
? Dr Gregory C. Johnson - NOAA/Pacific Marine Environmental Laboratory
? Prof Reto Knutti - Institute for Atmospheric and Climate Science, ETH Zurich
? Nicholas Lewis - Walden
? Prof Ulrike Lohmann - Institute for Atmospheric and Climate Science, ETH Zurich
? Prof Jochem Marotzke - Max Planck Institute for Meteorology
? Dr Gunnar Myhre - CICERO (Center for International Climate and Environmental Research - Oslo)
? Dr Drew Shindell - NASA Goddard Institute for Space Studies
? Dr Bjorn Stevens - Max Planck Institute for Meteorology
? Prof Myles R. Allen - Environmental Change Institute, University of Oxford
Most of them certainly seem to be involved with the climate.
It doesn't look like the "consensus" ECS of 3C by the IPCC is very strong. This is one of many recent papers advocating a lower climate sensitivity to CO2.
And as Jeff M points out, it's nice to see the scientists highlighting the uncertainty. Of course, uncertainty also applies to the 3C estimate as well.
Note as well a post by one of the authors on this paper:http://bishophill.squarespace.com/blog/2...
First I doubt that a real climatologist would have written that.
Second any bozo can refer to him or herself as a climate scientist, this doesn't require a degree in climate science, nor does it indicate they received and climate education.
Third if you read this you will discover that your link is a letter to the editor which was published online
If I am reading you right it doesn't sound so about-face as you seem to be implying. I have generally differentiated among climate scientists, activists and extremists (on either side of the argument) and the media. Actually, I think it must be kind of tough on the media to sensationalize what science has been telling us in some regards because more science is dispassionate than otherwise, so the media has to focus on guys like James Hansen, Al Gore, Lord Monckton and who knows who else as well as making their own part of the three ring circus that climate change has generated.
It is a welcome report to me but a little too early to put on the party hats and hang the streamers.
Looking at the full article, in the conclusions, we see the following: "We note, too, that caution is required in interpreting any short period, especially a recent one for which details of forcing and energy storage inventories are still relatively unsettled: both could make significant changes to the energy budget."
http://www.uwe-merckens.com/bilder/Wette...
Though I will refrain from saying more and let someone else chime in after reading that article.
Edit: Based on the paper, I am curious where he came up with the number 3.44 W/m^-2 He states that F2x is the radiative forcing to a doubling of CO2 content and then plugs in the above number. He then states that a radiative forcing estimate of 3.7W/m^-2 would allow a shifting up of ranges by 0.1K.
Edit: Okay, the 3.7W/m^-2 number is taken from Myhre et al, 1998 which were the same numbers used by the IPCC and the equation ΔF = αln(C/C0) where α = 5.35
http://go.owu.edu/~chjackso/Climate/pape...
They are still studying "climate sensitivity". They have made conclusions based on a preponderance of evidence since they decided to accuse human induced CO2 of having a direct affect on the planet and causing it to warm profusely. This is the problem with their insinuations. They don't know how the planet handles itself yet, but I like the progress they are making to understand it.
We can always come up with profound accusations. Backing them up with facts is the hard part. I doubt that we are big enough yet to have a "profound" effect on the planet. Having a "profound effect" will take many centuries of total abuse and many times our current population to achieve. We are nothing but a "pin-prick" at this point in time.
That is from the abstract from a study published a couple of months ago. I don't see what is so earth shattering about their findings. The conclusion is that one set of modelers says that based on one decade of data, the most most extreme warming predictions are less likely -- but "one should not solely rely on a single decade".
Nevertheless, the idiot deniers are suddenly in love with modelers, claiming these guys must be the best modelers but then flat out ignoring what they actually say. Once again we see that one must be either truly ignorant or truly dishonest to continue to deny. At best, deniers are silly people.
People truly interested in the conclusions of this particular group of modelers from their particular calculations. can view the authors' own presentation of their findings here. (This is a large file to be downloaded, 38MB.)
http://www.eci.ox.ac.uk/people/downloads...
Among the points we know already that this model did not account for is the ongoing release of methane, nor the potential for a temporary slight reduction in forcings from solar activity -- either of which leaves the potential for the most extreme projections to be plausible -- though still less likely than the consensus.
***************************************...
An important quote in O.Mike's link ...
"We would expect a single decade to jump around a bit but the overall trend is independent of it, and people should be exactly as concerned as before about what climate change is doing," said Dr Otto.
Even given the fact that most AGW Deniers do not grasp the concepts of science, knowledge, and intellectual integrity, attempts to criticize scientists for doing science still seem incredibly lame.
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Paul's Alias 2 -
If I had not already known calculus, I probably would have flunked freshman physics. Introducing students to physics by making them use algebra to solve RLC circuits, blocks sliding down ramps, torque equations, etc. is enough to drive most sane people away from science.
So while the United Nations is SCREECHING that the planet has warmed faster since the turn of the century than ever recorded (July 2013): http://www.bloomberg.com/news/2013-07-03...
The actual science is saying (May 2013): "The rate of global mean warming has been lower over the past decade than previously." : http://www.nature.com/ngeo/journal/v6/n6...
Hmm, there appears to be a disparity. I wonder who might be telling us the wrong story.
-----------------------
"The rate of global mean warming has been lower over the past decade than previously. It has been argued that this observation might require a downwards revision of estimates of equilibrium climate sensitivity, that is, the long-term (equilibrium) temperature response to a doubling of atmospheric CO2 concentrations. Using up-to-date data on radiative forcing, global mean surface temperature and total heat uptake in the Earth system, we find that the global energy budget implies a range of values for the equilibrium climate sensitivity that is in agreement with earlier estimates, within the limits of uncertainty. The energy budget of the most recent decade does, however, indicate a lower range of values for the more policy-relevant transient climate response (the temperature increase at the point of doubling of the atmospheric CO2 concentration following a linear ramp of increasing greenhouse gas forcing) than the range obtained by either analyzing the energy budget of earlier decades or current climate model simulations."
http://www.nature.com/ngeo/journal/v6/n6/full/ngeo1836.html
You gotta love the jump from reality to conclusion regardless of whether or not the information supports the conclusion. The main theme of their position seems to be there is still much we don't know, but we know what we know and we believe what we we don't know is irrelivent, and since the "experts" don't know, we should all be extremely concerned, specially when bad weather occurs.
It is the start of a climb down, of course they can't say they were wrong, so they are just saying perhaps it's not as extreme as we first thought. and mixed with the usual science-speak and precautionary talk (to emphasize how important this and they are)
They got busted with fraud , they need to protect the life they have come to love over any thing else .Prison is not were they wish to go , but not a bad place for us to send them.
Probably not and you've certainly taken in out of context
yes, blah blah blah ......ad infinitum
"Exactly what is a Climate Scientist, definition needed please"
Someone who wanted to be a physicist, but could not understand differential equations and freshman physics.
Exactly what is a Climate Scientist, definition needed please.
