Let's focus this time on the comments, since I had a letter published.
First, Greig, a regular contributor:
Philip Machanick in the past you have vehemently argued that it is CO2, and not the sun, which is the major driver of observed global warming. And now, year after year, global temperatures stubbornly refuse to climb in correlation with CO2, and so you revert to using the sun to explain. Like Dr Kevin Trenberth you are wedded to an opinion which you want the data to fit, and like him you saying “there should be even more warming . . . the data are surely wrong.”
Greig, CO2 drives the trend for the simple reason that there is no trend in natural factors, whereas atmospheric CO2 is increasing exponentially. The science says there's a logarithmic relationship between climate sensitivity and CO2 levels, implying we should over the long term see a linear increase in temperatures if the basic science is correct. The purpose of detailed models is to narrow the range of uncertainty, not to predict the basic effect. We are currently at a solar low, but the multi-decadal trend in solar insolation is flat. Same for ENSO. We had a big El Niño in 1998 and more recently a La Niña. The net effect of these things is zero, but pick a time when they are all pointing up or all pointing down, and you get a short-term high or low. Trenberth's comments were in a private email, a musing with colleagues, who pointed him to evidence that he was wrong. Much as I am loath to use stolen material, since it's out there and being misused, here is one of the responses by a colleague to Dr Trenberth:
I look at this in two ways. The first is to look at the difference between the observed and expected anthropogenic trend relative to the pdf for unforced variability. The second is to remove ENSO, volcanoes and TSI variations from the observed data.
Both methods show that what we are seeing is not unusual. The second method leaves a significant warming over the past decade.
Next, Ian 11:39am (you will have to page through the online comments to find all of these):
Philip Machanick Did the models predict that the global temperature increase would lessen over the last 10 years?. That these years are the hottest 10 since whenever really isn’t a valid argument despite those such as v who claim it is. Fact is that the increase over the decade has been less than predicted. Now why is that? [snip] And incidentally Professor Latif who is a climate scientist, has made and is still making comments that suggest the world is not about to turn into a heat ravaged dust bowl just yet
No, the models do not make predictions for as short a period as 10 years. But see above about removing known effects like ENSO. See also here how solar output does not correlate with temperature as it should if there were no interfering artificial effect, and another very clear illustration here of how temperature and solar output have diverged. Also, I illustrate that you can add a strong artificial upward trend to a temperature record that is essentially flat and still find a 10-year period with a strong downward trend.
You are wrong in your interpretation of Latif's comments, as I've indicated before on this site and in more detail elsewhere.
Philip (not me) 2:27pm:
Gosh all these people ignoring the hacked emails and documents showing what nasty little con artists the CRU are. In ignoring them they are behaving just like ahh… I don’t know maybe like holocaust deniers.
Or maybe they don't agree with the principle of stealing private communications? How about challenging the deniers to reveal all their emails for public scrutiny? That would make for interesting reading. Things colleagues say between each other are often unguarded, said without thought as to correctness or unintended consequences. Why should we all take exquisite care in every private conversation that we don't ever say anything we don't really mean, in case someone is eavesdropping? What kind of world would that be?
de Brere 01:27pm
Philip Machanick. Spot on, you do validate a theory by testing its predictions against observations. However, the prediction-observation link needs to be 100% accurate once other factors are taken into account. Otherwise the other unknown or unaccounted factors may themselves be the source of the observed variation, and not the theorised cause; in this case, GHGs. In that respect, all the tens, hundreds of billions invested in the “science” of AGW in the last two decades has spectacularly failed to come up with models that provide even moderately accurate prediction (or explanation) of observed climate change; far less of the individual weather events that go to make CC up.
De Brere, I've covered your misconceptions about how science works earlier. For your benefit I'll summarise again briefly here. Science in the real world is never 100% exact. Handling errors and uncertainties is a standard part of applied science. If you want exact answers, do pure mathematics. As for these astronomical numbers for the cost of climate research, what are your sources? I found a comparison of current US military and climate change-related funding and:
- excluding the recovery package, US military spending outranks climate spending 90:1
- even within climate spending, much more is spent on energy that on climate science
And finally, climate science is not about predicting tomorrow's weather. ENSO and the solar cycle are not fully understood, and have a bigger short-term impact than increasing CO2. However, if you keep increasing greenhouse gases long enough, you create a trend that breaks out of short-term variation. Where's your evidence that that is not happening? How do you explain that contrary to the strong downward pull of natural factors the last 10 years or so, the temperature trend is still slightly up?
Having dealt with comments about my letter and comments, I'll let Stephen Morgan 05:47pm have the last word:
Okay - so apparently these hacked emails are SO important that they change the case. So, can somebody tell me what they say. Only not just the ones that apparently give reasonable cause to doubt a few scientists, but every single one of these thousands of emails?
If you think the emails matter, then you will obviously review ALL of them, understand the context of ALL of them, be able to balance the views presented by ALL of them, and be able to come up with a reasonable theory that is supported by the contents of ALL of them.
To do otherwise is selective, prejudicial, and inevitably driven by a desire to support or discredit a specific cause rather than to seek any reasonable explaination.
It’s called denialism for a reason - it is the methodology of those who seek to deny rather than to discover, to obfuscate rather than to explain.
AGW IS widely accepted because it IS widely understood by those who support it. It is popular because it is far more reliable and consistent than any other option.
Is it proven - NO! Is it undeniable - NO! Just do as I asked - come up with something positive that offers an alternative, not just continued hackneyed attempts to sink a battleship with a pin-prick!
Well, quite.
