45 replies to this topic

[still learning]

arboramans, on 26 February 2012 - 06:50 PM, said:

The crux of the skeptical argument - and the point that should be being debated is the role of feedbacks in the system......

....The direct effect of CO₂ is well-established physics, based on laboratory results, and known for over a century....
.....Feedbacks are due to the ways the Earth reacts to the direct warming effect of the CO_2......

There are elements of truth in the arguments advanced by David Evans.  The direct warming effects of CO2 are only part of the picture but that part is agreed upon by even skeptical scientists. (Apparently not by denier non-scientists though.)  That climate scientists agree that the amplification is ablut three is true.  It might be true that some skeptics agree that the amplification should be 0.5 instead of 3.
So which is right?  3 or 0.5 or something else?

Regarding what supposed to be presented in Evans' Figure 3, comparing the predictions of a climate model in 1988 and some satellite measurements, another view is presented here:  http://www.realclima...88-projections/  
Also  "Climate model results summarized by the IPCC in their third assessment show overall good agreement with the satellite temperature record... at :  http://en.wikipedia....re_measurements  
Near as I can tell, the satellite data presented by Evans isn't equivalent to what the climate models do, is a sort of apples-oranges comparison.

And so on.  

Evans has advanced the main arguments shown in the Arbormans post before, with some additional material that near as I can tell doesn't make it any more relevant than before.

One really telling bit that Evans wrote is:
"On the other hand, the rise in air temperature has been greater than the skeptics say could be due to CO₂. The skeptic’s excuse is that the rise is mainly due to other forces – and they point out that the world has been in a fairly steady warming trend of 0.5°C per century since 1680 (with alternating ~30 year periods of warming and mild cooling) where as the vast bulk of all human CO₂ emissions have been after 1945."
So Evans wrote that "other forces" have caused much of the warming that has been experienced so far.
What other forces?
What other forces?
Again, what other forces?  Something magical?  Wishful thinking?  Prayer?
The very thing that Evans denies is my guess, the feedbacks, mainly water vapor.

Oh yes, "fairly steady warming...since 1680"?
Come on.
See:  http://en.wikipedia....ick_controversy
Essentially all the warming after we started using fossil fuels extensively.

Previous discussion of Evans' arguments here:  http://www.skeptical...-goes-cold.html
On David Evans: http://www.desmogblog.com/david-evans

[Shortpoet-GTD]

arboramans, on 06 March 2012 - 03:50 PM, said:

The warming in the late 20th century could be a total anomaly due to meassurement errors.

Then I guess we need a massive recall of every temperature gauge from every country in the world.

[still learning]

arboramans, on 06 March 2012 - 03:50 PM, said:

That's if you think the temperature records are accurate, not biased by Urban Heat Island effect and not measured basically in northern hemisphere land areas. The warming in the late 20th century could be a total anomaly due to meassurement errors. Otherwise how do you explain the proxy divergence?

Arboramans, by "That's if you think the temperature records are accurate..."  you are referring to what?
The part in the last post that I made where I linked the Wikipedia hockey stick article?

If so, then yes, I accept that the records are accurate enough and that the appropriate corrections have been made, including correcting for the urban heat island effect, so that the overall results are trustworthy.

"The warming in the late 20th century could be a total anomaly due to meassurement errors."

Is it your view that the late 20th century warming is due to meaurement errors?  If so, why do you hold that view?

A lot of people have gone to a lot of work to try to get a good idea on how much the Earth actually is warming (or cooling). That amount of warming (or cooling) is often summarized as a global temperature anomaly, a composite figure derived partly from actual air temperature measurements, partly from oceanographic measurements and partly from satellite data.
There is more than one ongoing effort to consistently quantify the amount of global warming (or cooling) that is going on, with the one at NASA GISS lnked to here: http://www.columbia....Temperature.pdf

"Otherwise how do you explain the proxy divergence?"
Which proxy?  The "UAH monthly...anomalies" line on figures 3 and 4  of your 26 Feb post?
I don't explain it.
As I said before, I think those figures are a sort of apples-oranges comparison.
Eyeballing, I see in that UAH line a distinct right side upward overall slope at about the same angle as the scenario A slope in figure 3 or "best estimate" in figure 4.  The slope of the line, the trend, is what's important here.  Nobody should place much trust in my eyeball guess though.  Somebody could number- crunch the original data that was used to make the graph and see if my eyeball guess is OK or not.  The vertical placement of the starting point of the line is kind of arbitrary, near as I can tell without some explanation by the author of the graph.  Apples and oranges comparison then.
Figure 2.5 of this NOAA report:  http://www1.ncdc.noa...2010-lo-rez.pdf does use  satellite information to show that the lower troposphere has warmed.

[kate]

Living on the edge of Lake Michigan, I appreciate how much changes in the environment can directly affect our weather.  A warm winter, such as the one we are currently experiencing (it's 80 degrees F. today!) keeps the lake waters relatively warm.  Should an icy blast head our way from the Arctic as it often does in winter, the cold winds hit the warmer lake waters and become our infamous "lake-effect snowfalls."  The Arctic Express blasts fairly unimpeded down through the Canadian plains in most years, although this year we saw far dewer than normal.  Less snowfall means dry, dusty planting fields in the spring, less topsoil, weaker crops and a general pox on the food supply.

[Shortpoet-GTD]

http://www.newscient...er-winters.html