EM these are not my years but yours, when you posed this

Every year since 2003 has a 5-year anomaly average of 0.57 0.58 or 0.59.

After 9 months the 2014 average is at 0.68 and rising. This would make the most recent 5-year average 0.61. Both are record values.

I see no mention of the 0.41 so you can't pull that one out of the hat like a magic rabbit. If is was not worthy of mention then why now.

As the Giss data starts in 1882 at -0.19C and goes to +0.61 by 2014 that is 0.8C in 132 years, so what.

Sandy, it is definitely a OR. If CO2 levels were to drop for several years with emissions unchanged, how could anyone argue the we need to cut emissions. If temperatures (broadly measured) fell for a significant period we'd have to conclude that there was something wrong with our understanding of the climate. Similarly if secular glacial retreat turned into secular advance, that would seriously challenge any idea that temperatures were rising.

Why do you think it should be AND?

Raff, while you're in a sensible groove, I'll say this:
Theoretical calculations of warming due to CO2, and water vapor feedbacks, might possibly be correct, yet hidden by natural variations in the system. Temperatures could fall, and so could CO2, yet the basic tenets might still be correct.

But how would we know?

When climate models start predicting the downs as well as the ups, then, and only then, will I start to be persuaded that the models are an adequate description of the physical world.

> Similarly if secular glacial retreat turned into secular advance, that would
> seriously challenge any idea that temperatures were rising.

What about polar ice levels? Aren't these supposed to be one of the things that are supposed to be affected first?

What about polar ice levels? Aren't these supposed to be one of the things that are supposed to be affected first?

Nov 10, 2014 at 4:30 PM | Unregistered CommenterNial

Which polar ice levels?

In the Arctic the long term trend of both land and sea ice is down.

In the Antarctic land ice is decreasing and Winter sea ice is increasing.

Note that the Arctic is strongly influenced by heat input from lower latitudes. The Antarctic is more isolated, with much less heat moving South, at least so far.

Where data is available the Arctic is one of the fastest warming areas on the planet. Except for the West Antarctic peninsula the Antarctic has been the slowest.

Breath of fresh air

What 0.41?

If you look at the GISS tabular data the 5-year average centred on 1998 is 0.44. That is what I referred to.

Raff
OR because any single one of your list will disprove the theory. This goes some way to explaining why EM is so keen on 5 years of measurements/adjustments.

Read about logic

michael hart, when people don't refer to me as "green slime" or as "troll" or other apparently acceptable insult, I can groove sensible. Doesn't take much to knock me out of that groove though.

Clearly natural variation such as extended volcanic activity or decreased solar activity can hide CO2-induced warming. Such cases, where there is a clear cause, would obviously not disprove AGW :-) Models already 'predict' cooling from volcanoes and solar activity, so perhaps you can already be persuaded that they are adequate. Maybe however you are referring more to variation where there isn't a known driver? To believe what models say only if they were to go rogue (i.e. predict things for which there is no apparent mechanism) would be perverse, wouldn't it? Where role for "validation" then?

Nial, polar ice levels might be affected by changes in ocean currents or winds caused by AGW. Is it beyond imagination that such changes could increase ice levels in an otherwise warming world? I don't really know.

Sandy, do we need to study digital logic to know the meaning of AND and OR? What I was referring to was clearly OR (to me anyway) - any one could falsify. What is the connection with "5 years of measurements/adjustments"?

The argument that AGW is "not falsifiable" is not sensible.

Raff
Normally those of a Warmist view would require all of your list to be met, and more besides. Entropic man seems to have been using 5 years data to dispute the "pause" although it seems pretty iffy to me. I just wanted i's dotted and t's crossed so that it was very clear what you were saying. Any one of the key indicators of global warming ( natural or man made) moving to the opposite proves cooling ( man made or natural).

All that's required now is what stabilisation indicates.

I don't think I said that anything "proves cooling". We were talking of falsifying AGW - i.e. the theory that our emissions cause what we know as "climate change". If you want to introduce a different hypothesis - that of a cooling earth, you'll have to assemble your own evidence.

BTW in my reply to Nial above, I was referring to the Arctic. It is clearly not beyond imagination that Antarctic sea ice can increase in an otherwise warming world (although you might not accept that it is warming).

Raff,
my mistake, sorry yes you did indeed say disproves AGW. I was away from home over the weekend and only had the iPad which made proof reading a bit tricky.

Anyway the point remains the same, if any single one of these fails to match the increase in CO2 the AGW falls?

For clarification from where would you take your starting point? Perhaps you'd start now and work back?

SandyS

I was comparing 5-year averages at the beginning and end of the pause. The average centred on 1998 was 0.44 the average for the five years centred on 2011 is 0.58 and the 2009- 2014 average looks likely to be 0.61.

Why use 5-year averages? It damps down internal variation in weather nbetween individual years and reduces the effect of cherry picking individual years as starting points.

> I was comparing 5-year averages at the beginning and end of the pause. The average centred
> on 1998 was 0.44 the average for the five years centred on 2011 is 0.58 and the 2009- 2014
> average looks likely to be 0.61.

EM, as an ex science teacher I'd have thought that you would realise that a 5 year average centered on the start of the pause still includes years from before the 'plateau', supressing the value.

If you look at the values from 2002 ish (from memory), there's been very little change since then.

Even the main climate scientists are admitting to the pause, which is why they are scrabbling around for a reason for it. I tend to view 2002 as the true beginning of the pause but using the same rule pushes the start of the rise forward too. Bottom line - there have been a lot more years since 1950 in pause than rise. And of course the time scale is less important than the CO2 emitted. At the very least, the pause casts the acceleration theory into doubt.

Incidentally, part of the theory about the Arctic was that declining ice would have an additional warming effect. A tipping point has been reached ahead of schedule and yet there has been no significant warming.

Thanks for the inputs re "The Pause", I'm in the Martin A /Nial camp.

Whether there is a pause depends very much on what you measure.

I agree with Tiny CO2 and Martin A that 5-year average land/ocean surface temperatures levelled off in 2002. One reason for choosing 1998 is the recent sceptic meme of the 18 year pause, which presumably started in 1996 so the 1998 5-year average includes 1996, 1997 1998, 1999 and 2000.

If it was only surface temperatures there would be no problem.

Unfortunately a number of energy sinks are still taking up heat. Arctic and Antarctic land ice continues to decrease, taking up 500 cubic kilometres worth of latent heat of fusion each year. Sea levels continue to rise at 3.2mm/year, of which half is that 500km3 of ice melt and the rest is thermal expansion.

If the energy budget balanced I would find a pause in warming more credible. Instead energy continues to accumulate in the climate system.

I have been thinking of a pause related hypothesis test. I could use some input.

First a starting date for the pause. When did this hypothetical pause start? Different sceptics have used 1996, 1998, and 2002.
Please agree on one, temporarily at least.

Secondly two alternative pause related hypotheses.

From my side: The rate of warming from 1970 to the onset of the pause represents the long term trend.

From the sceptics: The rate of warming from the onset of the pause to 2013 represents the long term trend.

Happy with that? I'm quite happy to change the latter if you have a better wording.

I prefer GISTEMP, but will happily use anything Woodfor thetrees can handle.

Mike JacksonJackson, Tiny CO2

Actually the null hypothesis should be that the climate since 1880 climate is constant.

The two competing alternate hypotheses would then be:-

Climate variation since 1880 is due to natural variation.

Climate variation since 1880 is due to AGW.

In practice both probably contribute and the real problem becomes to decide how much.

michael hart
You're wasting your time with EM. I have tried to explain numerous times that the sceptic position is that the null hypothesis is that climate variation is natural and it is up to those who disagree to put forward evidence that proves otherwise.

Nov 12, 2014 at 10:46 AM | Registered CommenterMike Jackson

Mike Jackson, the thought had occurred to me too...

EM's null hypothesis is somewhat like that of a person who flips a (theoretical) 'unbiased' coin 1000 times and expects precisely 500 heads and 500 tails. The universe doesn't work that way in statistical mechanics explanations of thermodynamics, and it doesn't work that way in real-world experimental situations either. It's ironic, really, for a person who uses "entropic" as part of his moniker.

EM The air temp has been the main metric for assessing climate and many of the proxies and calculations are pegged to it. All those ice cores are all air temperatures. If you decide that ocean temps can start to significantly vary independently of air temp then what does that do for all those scenarios for the past they've constructed? Of those ocean proxies I've seen, current conditions are just fine. On the chilly side in fact. More to the point, the Southern Hemisphere shows a lot less warming than the Northern and it's dominated by water. The oceans are warming no faster than they were in the 80s and 90s despite the missing air increases. Where is the missing heat? Trenberth's travesty.

Since we've only been measuring ocean temps in any volume and quality since ARGO was started, the records are very, very short. How do we know they weren't warming faster 30 years ago or 130 years or 1300 years? The old records are very dodgy and the splices between data series alway result in a jump in temperatures. How convenient. But ok, scrap the models and rewrite the rules so that the oceans drive air temperatures but at the same time can be substantially affected by air temps. How does that work? When does that work? What triggers the oceans to store energy rather than lose it? Can the models say anything useful without decent measurements as input?

Every time they make an excuse for a lack of air warming they have to go back and apply it to the past. eg Chinese sulphur emissions increase = cooling, EU and US reductions in the 70s and 80s = warming. Fundametally, changing the programming falsifies past versions of the model. Now that's perfectly fine except they said they understood how it worked. You only get one chance to be taken on trust. After that you have to prove your ability. That means setting targets that should they not be met, falsify the new models too.

A timely bit of research.

http://www.eurekalert.org/pub_releases/2014-11/awih-hva110714.php