2012-02-06 18:12:09Breaking News....The Earth is Warming...Still
Glenn Tamblyn

glenn@thefoodgallery.com...
121.214.66.44

Draft version here

Still needs lots more links and a final spell/grammar check.

2012-02-06 23:44:01
Kevin C

cowtan@ysbl.york.ac...
144.32.72.165

Looks very interesting! I need to read Meehl et al 2011.

Can I try out a counter-argument on you? Although it's only addressed peripherally at your post, so someone else may be in a better position to answer. (I'm always looking for the strongest possible counter argument to any argument I make. They don't often correspond to the arguments which deniers actually make of course, because the deniers aren't interested in understanding the system. Here's one which I think might be justified though.)

We know from the linearity of the forced response that the change in equilibrium temperature of the climate system varies after feedbacks roughly in proportion to the change in forcing. However, there is a certain amount of lag, with the oceans lagging further owing to their greater heat capacity.

The energy uptake by a component of the system will be roughly proportional to the difference between its current temperature and the equilibrium temperature for the current level of forcing.

Now, because the ocean temperatures take much longer to catch up, the difference between the ocean temperature and the equilibrium temperature for the current level of forcing is greater than that for the atmosphere, and as the discrepancy grows the heat uptake will move preferrentially to favour the oceans.

Now what happens if there is a levelling off in the forcing, due to aerosols or natural cycles or whatever?

The atmosphere has largely reached its equilibrium temperature, and so temperatures will also level off. However, the oceans are still lagging behind, and so will continue to warm.

Thus, to look at the Church heat content graph and conclude that forcing has continued to grow over the last decade at a similar rate to previous decades would be an invalid conclusion. In other words, it could be showing mainly comitted rather than new warming. That would be entirely consistent with a levelling off of air temperatures but continued growth in OHC.

What do you think? Can you spot any flaws?

2012-02-12 06:49:34
Rob Painting
Rob
paintingskeri@vodafone.co...
118.92.93.222

Glenn,

This post touches on quite a few things I've covered in a post on Loeb (2012). I've only skimmed it but will have a decent read later on today. Thought this might be of interest to you, it's a graph of OHC based, not on the NODC (Levitus methodology), but on PMEL/JPL/JIMAR:

Note that the rate of ocean heating (a) since about 2006 is greater for the 0-1800 mtr layer, than for the 0-700 mtr layer, up to 2010. Of course the climate has been in a dominant La Nina period for most of this time. Very interesting huh?

2012-02-13 18:33:16
Glenn Tamblyn

glenn@thefoodgallery.com...
124.184.16.161

Kevin. Sorry to take so long to reply. My laptop died so my internet access has been sporadic till now.

 

To your question. My piece is aimed at a lower level audience for whom the meme 'warming has stopped' simply translates as 'it was all a false alarm'. There are two ways an audience could take the idea that warming has stopped. The simplistic lay view, wrong but common, that if warming has stopped, the forcing has gone away. The more sophisticated view is that the forcing may have slowed its increase, plateaued or even dropped. But it is still non-zero.

So to the simpler 'forcing has stopped argument', accumulation of heat anywhere is the counter to it. A forcing in the planets energy balance must exist for total heat to keep growing. And this is the key point of the post.

To the lesser argument that forcing has changed but not gone to zero. It has plateaued or dropped; what we would expect to see is that total heat content rise will start to slow, approaching an asymptote which is final thermal equilibrium for the whole system at which point the forcing will have declined to zero. In fact it is the continuing rise in the forcing that prevents the thermal response from catching up with it and showing something like an asymptotic behaviour. So to differentiate between reduced increase, plateauing or even decline in the forcing vs continued increase we would need to look for an asymptotic like character to the total heat content graph from Church etc. It is entirely possible that in the last decade a weak solar cycle and increased aerosols may have been strong enough to negate some of the increased forcing due to GH Gases. In which case a diminution of the Total Heat curve slope would be expected. Church dosen't show this strongly but the time scale for the data is too short for anything significant to show up. But there is nothing in the data suggesting that forcing has gone to zero.

If forcing had for some reason gone to zero, one would expect that since warming of the atmosphere had outpaced warming of the oceans, a heat transfer from the atmosphere to the oceans would then occur to restore thermal equilibrium between them. Given that the thermal mass of the oceans is so much greater than the atmosphere, what we would expect to see is a significant drop in atmospheric temperatures to come back into synch with the oceans. In effect most of the atmospheric warming of the last 1/2 century would be reversed. And fairly quickly.

So we can be confident that the forcing change hasn't just gone away suddenly. Could the rate of increase in the forcing have slowed recently? Most certainly. But it is still an increase.

But to the core skeptic meme that 'warming has stopped' - translation 'forcing has stopped, it was all bullshit', the evidence is NO.

And the change in warming rates at different levels in the ocean looks to be a big part of why surface temps plateaued.

If Mother Nature wants us to solve the AGW problem, she sure picked a lousy decade to start playing silly buggers with ocean circulation!

2012-02-13 20:33:16
Glenn Tamblyn

glenn@thefoodgallery.com...
60.228.33.25

Good to go here

Rob, the other data is interesting. Basic take home message from all this is that warming hasn't stopped, its just happening somewhere else at the moment. And the 'it hasn't warmed since x' meme is perhaps the strongest on out there among the Joe Averages (as distinct from the denizens of the Denialosphere who pore over every tea leaf)

The key message from this meme is 'False Alarm. Move On Folks'. This is probably one of the most important ideas out there at present as far as the general public is concerned.

2012-02-13 21:13:34
Rob Painting
Rob
paintingskeri@vodafone.co...
118.92.83.34

Snap! I cover much the same ground in post on Loeb (2012). I also emphasize the point that the persistent energy imbalance at TOA is future global warming that has already been committed too.  

2012-02-14 08:48:04
Glenn Tamblyn

glenn@thefoodgallery.com...
121.218.74.26

This is a subject that is probably worth a few posts from different angles. The 'Its Not Warming' meme needs a stake driven through its heart. Thats also why I didn't make this too technical, more evidence based, to keep it accessable to the lower end of the readership

Be interesting to compare it with yours.

2012-02-14 08:50:03
Rob Painting
Rob
paintingskeri@vodafone.co...
118.93.133.33

Yup, we're singing from the same hymn sheet. I agree wid ya' - this zombie myth needs to have its head seperated from its shoulders with a 12 gauge!

I'll put it my post up for review later today. We just have to keep writing about certain aspects of it, so the ideas (facts!!!) become entrenched in our readership. 

2012-02-15 14:48:21
Rob Painting
Rob
paintingskeri@vodafone.co...
118.93.236.74

Finally got around to reading it Glenn, I like it. A couple of nits:

- "And what does this tell us about where we need to set our boundaries (?)"

-  "Warming says that more greenhouse (GH) gases"

And you seem to use capital letters in a few places where it doesn't seem justified. It's not something I get bent out of shape over, but someone in the comments threads inevitably complains about it.

We probably need some simple graphics to explain this, so I've put it on my to-do list.

Now the following image (from Johnson & Wijffels 2011)  isn't of a 'hiatus decade', but it is interesting that the downwelling circulation (based on the warming trend) appears quite strong at around 35°N and 35°S.

2012-02-15 14:54:03
Rob Painting
Rob
paintingskeri@vodafone.co...
118.93.236.74

Okay, forgot thumbs up.

2012-02-15 18:29:02
Glenn Tamblyn

glenn@thefoodgallery.com...
121.216.23.58

Thanks Rob, small changes made.

 

Perhaps a general graphic of circulation patterns would be good if we can find one. Not so much temperature profiles as 2D/3D graphics of water movements. The idea being that that gives a reason for why the hiatus periods can come about - crank this up a bit and et voila. Suitable for my simpler piece. Then yours gives more technical detail.

2012-02-15 22:25:40
Kevin C

cowtan@ysbl.york.ac...
144.32.72.165

Thanks for the analysis Glenn. Yes, I think that clarifys my thinking.

A flattening in forcing would certainly lead to a stronger effect on air temps than sea temps because the sea temps are lagging further.

I guess part of the issue is the distinction between forcing and energy imbalance, and forcing being relative to an arbitrary start date. The positive slope of the Church data certainly shows that the energy imbalance is still positive, to within the limits of the data, which means that the system as a whole hasn't caught up to the equilibrium temperature for the current level of forcing (but of course that can take centuries, if the whole ocean has to heat through).