BBD,
You've committed two serious blunders in this thread. First, the IPCC-synthesis-report like trend drawings, two, telling matthu that you can evaluate whether two trends are significantly different from one another, by sheer 'intellectual honesty'.

What's up, mate? You did something weird to begin with, ... why are you compounding your error, by making further mistakes? You cannot just eyeball and use intellectual honesty to evaluate differences between trends.

Shub

Fine. I disagree with you, of course, but have it your own way.

What about decadal trends?

CRUTEM3 land and BEST 1900 - present, common 1981 - 2000 baseline, 10 year means

Notice something... unusual about the period ~1975 - present?

No ... it's going up? Is that unusual?
It would be more meaningful perhaps if you plotted world temperatures against CO2 emissions rather than land temperatures against time.

Sorry - "decadal means" not trends.

matthu

You aren't answering the question.

Since you mention it, CO2 concentrations should not be combined with a temperature time-series. It's a bad habit.

The entire climate system response to CO2 forcing does not correlate with CO2ppmv instantaneously. This is elementary stuff.

By the way, if you plot 60 year means you get a very nice curve to eyeball.
No dip in the middle.
Not quite sure whether it is any more or less meaningful.

I did answer the question: you asked whether I noticed anything unusual in the period after 1975.
I assumed that you meant "statistically unusual" rather than artistically unusual.
My answer was "No".

Why do you think it is any more meaningful to plot temperature against time?
Do you think temperature has a dependency on time?

BBD,

Yes, I have read Barry Bickmore's critiques, thank you.

I'm perfectly to happy to accept the GHE and increasing emissions as an adequate motivation for decarbonization. There is little doubt in either of these findings, and I think it is damaging and pointless to use more detailed argumentation to try to establish a case. The IEA report - or at least the parts I've seen - shows the direction in which we are headed, and illustrates the need for diversification through R&D.

Night all.

matthu

I assumed that you meant "statistically unusual" rather than artistically unusual.
My answer was "No".

You might want to share your reasoning in more depth if you wish to convince on that one.

Why do you think it is any more meaningful to plot temperature against time?
Do you think temperature has a dependency on time?

I sense confusion.

As I said earlier, the entire climate system response to CO2 forcing does not correlate with CO2ppmv instantaneously.

Philip

Thanks for the response.

Isn't this fun?

À demain.

Which part of my response do you not understand?
You asked me whether I saw anything unusual in a particular part of your chart which showed 10-year means plotted against time. I said no, I did not see anything unusual.

May I ask you perhaps to share with us what we were meant to see - and how would we have been able to recognise that it was unusual in any sense (in the absence of any statistical tests)?

By the way, here is a clue: when you have hightly autocorrelated data, you often get unusual looking charts. Whether they are in fact statistically unusual or not needs to be determined by proposing a model and then testing the data against that model. Not by eye-balling the chart.

matthu

There are some models, I believe ... ;-)

matthu

I understood your response, but did not agree with it.

The problem here is that, bar a contrarian minority, everyone else sees what is actually there: an increasing rate of warming 1900 - present.

Your apparent prior commitment to the unsupported hypothesis that CO2 is not warming the climate system is interfering with your ability to think.

Actually, can I ask: what exactly is your position on RF from CO2 as an increasingly important factor in GAT change?

I don't know if you are a lukewarmer, or a flat-out contrarian, or what.

You see an increasing rate of warming 1900 - present? Well then, you need to test whether that increase is statistically significant. By the way, I see a dip in your chart.

When you say "Your apparent prior commitment to the unsupported hypothesis that CO2 is not warming the climate system is interfering with your ability to think" you are being presumptive and trying to be rude at the same time. There is nothing wrong with my ability to think.

RF from CO2 as an increasingly important factor in GAT change?

RF? Not sure exactly what you mean here.
increasingly important factor? I am not sure whether it is even an important factor. Certainly this is not the scientific consensus.
GAT? Is that what you are trying to measure with land thermomemeters?

This is my understanding of the consensus as I outlined to Richard Betts (who agreed with it)
1) global warming is real (whatever that means)
2) man is having an impact
3) at least some of the impact is likely caused by CO2 emissions

I can live with that (and argue about the meaning of the first point),

Anything further than that e.g. increasing rate of warming, increasingly important factor, catastrophic consequences etc. remain to be proved.

I will leave you to sleep and ponder over these points: I should confess that I am probably in a different time zone to you and therefore at some advantage.

matthu

RF? Not sure exactly what you mean here.

This is worrying. RF = radiative forcing.

increasingly important factor? I am not sure whether it is even an important factor. Certainly this is not the scientific consensus.

Er, what? You just said that RF from CO2 emerging as the dominant climate forcing is 'not the scientific consensus'.

The scientific consensus is that RF from CO2 is emerging as the dominant climate forcing. You leave me scratching my head.

GAT? Is that what you are trying to measure with land thermomemeters?

See Nov 10, 2011 at 11:41 AM. After mulling over the graph, follow the link to this discussion of the possible bias in RSS/UAH TLT analysis. This is how open-minded inquiry works. You read everything you can, and think carefully.

No - that is not part of the consensus. See my earlier reply.

matthu

at least some of the impact is likely caused by CO2 emissions

Most of it is, and the effect will steadily intensify over time. That is the scientific consensus and we both know it. That's what Richard Betts thinks, and I invite him to comment if I misrepresent him.

Time, again, for a pretty picture.

No trends, no pre-1900 data.

Just a curve.

Of course, it's all nonsense.

"Most of the impact is likely caused by CO2 emissions, and the effect will steadily intensify over time"

BBD - this is your belief - but certainly not the scientific consensus. And I gave Richard every opportunity to correct me here.

You also omit the effects of deforestation, cosmic rays. oceanic oscellations. Plus numerous other unlisted effects. And the fact that the effect of CO2 emissions are logarithmic and hence not intensifying over time unless you assume all sorts of other unproven side-effects.

Sorry, BBD. You assume much more consensus support than is actually the case.

Just love the statistically ignorant ranting on this thread.