A new paper has been published in Science, 3rd January, that uses the words ‘natural variability,’ the abstract copied below is self explanatory:
The Spatial Pattern and Mechanisms of Heat Content Change in the North Atlantic
M. Susan Lozier 1, Susan Leadbetter 2, Richard G. Williams 2, Vassil Roussenov 2, Mark S. C. Reed 1, Nathan J. Moore 3
1 Division of Earth and Ocean Sciences, Nicholas School of the Environment and Earth Science, Duke University, Durham, NC 27708, USA.
2 Department of Earth and Ocean Sciences, Liverpool University, Liverpool, L69 3GP U.K.
3 Division of Earth and Ocean Sciences, Nicholas School of the Environment and Earth Science, Duke University, Durham, NC 27708, USA; Current affiliation: Department of Geography, Michigan State University, East Lansing, MI, 48823 USA.
Abstract:
The total heat gained by the North Atlantic Ocean over the past fifty years is equivalent to a basin-wide increase in the flux of heat across the ocean surface of 0.4 ±0.05 Wm-2. We show, however, that this basin has not warmed uniformly: though the tropics and subtropics have warmed, the subpolar ocean has cooled. These regional differences require local surface heat flux changes (±4 Wm-2) much larger than the basin-wide average. Model investigations show that these regional differences can be explained by large-scale, decadal variability in wind and buoyancy forcing, as measured by the North Atlantic Oscillation index. Whether the overall heat gain is due to anthropogenic warming is difficult to confirm, since strong natural variability in this ocean basin is potentially masking such input at the present time.
Jennifer Marohasy BSc PhD is a critical thinker with expertise in the scientific method.
Natural variability? Back on a December 27 posting at RealClimate,
http://www.realclimate.org/index.php/archives/2007/12/a-barrier-to-understanding/#more-497
Gavin Schmidt was being questioned about the recent absence of a positive trend in global temperature. Refer to 56.
Daniel Klein wrote, “…How long would it need to be for the 1998 record global temperature to not be exceeded (or if you prefer, a “non-trend” beginning at that date) for you worry that something has been missed in your understanding? 2010? 2015? 2020? 2030?”
Gavin replied, “…To answer your question though, 1998 will likely be exceeded in all the indices within the next five years – the solar cycle upswing into the next solar max will help, and the next big El Nino will probably put it over the edge.”
Sounds like Gavin’s relying on natural variability to keep warming afloat.
So he didn’t actualy answer the question, did he?
Mark’s charts, http://www.geocities.com/mcmgk/Charts.html?1197437190605 adjusted for El Chichon and Pinatubo, make it clear that there has been an unambiguous downwards trend since 1992 (16 years)and a plateau since 1983 (25 years).
Must be time for the Climate Crooks to switch to 30 year moving averages so they can obscure the new trend.
Bob – “Sounds like Gavin’s relying on natural variability to keep warming afloat.”
No as he actually understands some of the processes that drive the climate he realises that the enhanced greenhouse warming is always going to underly the natural variation present in all climate systems.
Right now La Nina is cooling temperatures slightly as the ENSO has such a profound effect on the Earth’s climate.
Nobody denies that there is natural climate variability. In fact this variability could become more pronounced with more energy available in the climate system.
“Nobody denies that there is natural climate variability. In fact this variability could become more pronounced with more energy available in the climate system.”
Looking for the reverse gear? Are we?
To clarify!
The reason I said that, is that in the last 3 years I visited many sites, yours as well as RC, and I could not find anything as clear an indication to natural causes, as what you just wrote.
Contrary to some, I still keep an open mind.
Ian: He eventually answered. See the next few items on that thread. And thanks for the link. Could you point me to the data sources for those graphs? For the next couple of months, I’m stuck indoors, playing with Hadley Centre temperature data, the multiple studies of TSI, and the like. Volcanic aerosol adjustments would add another thing to the mix.
Ender: It appears to me, excluding natural oceanic temperature variations as the IPCC does, the only way for global temperature to stall is for the sum of the effects of an increase in aerosols and a decrease in TSI to equal that of the gains in anthropogenic greenhouse gases, which isn’t consistent with what we’re being told by the IPCC. This would put a minor drop in solar irradiance and a minor increase in aerosols on a par with the total net increase in anthropogenic forcings.
http://www.realclimate.org/images/ipcc2007_radforc.jpg
Nobody denies that there is natural climate variability?
Has the IPCC determined and communicated what impact the natural increase in SST, caused by the PDO or its big brother the IPO, has on the calculation of global temperature during the second half of the 20th century? That’s a lot of surface area for a natural rise in temperature to go unaccounted for. Did they detail the teleconnections with land masses and other oceans?
Bob:
You missed the lively discussion on another thread that got into this:
http://www.jennifermarohasy.com/blog/archives/002643.html#comments
See Dec. 30, 3:39 PM posting
On another note, the power of oscillations in ocean currents to alter surface climate is formidable! A study by McPherson & Zhang identifies a 25% drop in deep ocean upwelling off the coast of S. America from the 70’s to the 90’s(from 47 Sverdrups to 35 Sverdrups). Assuming a deep ocean temperature of close to zero and a surface temperature of at least 16 degrees, if you do the math a drop in resulting cooling effects of over 802 terawatts is indicated! Spread across the surface of the planet, this averages to over 4.5 Watts per square metre!
Brett – “Looking for the reverse gear? Are we?”
No – none of the underlying warming factors have decreased so there is no reverse gear at the moment. Until meaningful reductions in greenhouse gas emissions happens the warming will continue. Cooler and warmer natural variations will still happen around this basis of AGW.
Try and think about similar El Nino conditions like 1998 and then add on a degree of AGW warming. 1998 was bad enough let alone what a strong El Nino will be like with extra warming. So save the denialist back slapping until we go through a few more ENSO cycles.
“No as he actually understands some of the processes that drive the climate he realises that the enhanced greenhouse warming is always going to underly the natural variation present in all climate systems”
So there you have it.
The belief preceded the evidence and the human factor in global warming is entirely independent of the temperature data.
For the faithful, AGW is a priori knowledge in exactly the same way that the literal biblical account of Creation is to ‘creation science’.
Ooops – Calculation error! It’s 1.5 Watts per square meter, not 4.5.
Looks as though I was too harsh in saying that I would delete references to RealClimate. I don’t want to miss out on recent examples of RC shooting itself in the foot.
Mark, I know the link to the other thread had your references but is there any way you can add them to your site?
Very interesting point about the deep upwelling too. Is there more info? Why not a new post?
Paul, we must take our pleasures as they come.
“Mark, I know the link to the other thread had your references but is there any way you can add them to your site?”
Done my friend!:
http://www.geocities.com/mcmgk
As to the upwelling, I haven’t got too much information on that – just the one bit of information in terms of the S. American coast. The big question is whether such changes are symmetric or asymmetric.
This item by D’Aleo is interesting in terms of the relationsip between PDO/AMO cycles and global temperatures. This is likely to be a big piece of the puzzle in terms of figuring out what really drives climate change. The IPCC just shrugs its shoulders on this since it doesn’t support the AGW agenda.
http://icecap.us/docs/change/OceanMultidecadalCyclesTemps.pdf
The Tsonis et al ‘climate shifts’ paper gets my vote as the most interesting paper of 2007:
http://www.volny.cz/lumidek/tsonis-grl.pdf
the collective behavior of known climate cycles such as the Pacific Decadal Oscillation, the North Atlantic Oscillation, the El Nino/Southern Oscillation, and the North Pacific Oscillation were investigated.
Tsonis believes AGW is happening, he was investigating the existing climate systems that overlay it.
Tsonis accounted for all the temperature/climate shifts in the 20th century, and made predictions for future warming and cooling on the basis of a new dynamical mechanism. I don’t think he suggested that CO2 was driving the mechanism. How much man-made CO2 was in the atmosphere for the climate shifts of 1913 and 1942?
If we eventually manage to objectively work out the magnitude of AGW against the background of natural variability, we can add that in as well.
I’ll repeat the last line of the abstract for the NAO paper we are discussing on this thread for the benefit of SJT:
“Whether the overall heat gain is due to anthropogenic warming is difficult to confirm, since strong natural variability in this ocean basin is potentially masking such input at the present time.”
“In ‘Taken By Storm,’ Essex and McKitrick offer a scientifically sound argument that is against the mainstream. Let’s open up a debate and see who is willing to participate.”
– Professor Anastasios Tsonis,
Department of Mathematical Sciences, Atmospheric Sciences Group, University of Wisconsin-Milwaukee
mcafee vs avast
microsoft spyware remover