That's why the people who claim the cooling trend never actually give the temperature plot. They hope enough people will simply take their word for it. Then they quickly move on to the latest report of a frost somewhere in the world.

I have followed links. All I see are claims of a cooling trend, with no data to back it up, or a data sample that deliberatly omits 95% of the relevant info.

Why do you keep posting DWMT? Does it mean anything?

Grendel wrote on Nov 27^th, 2008 at 2:33pm:


Earth to Grendel - please come in Grendel

Didn't you even read my reply that talked about the equilibrium between CO2 and temperature?

How many times do I have to explain about the Milankovitch cycles?

http://en.wikipedia.org/wiki/Milankovitch_cycles

As far as I know, there was a gradual cooling trend over the last few centuries until CO2 concentrations started rising due to human activity. This caused an increase in average global temperature that is far more rapid than the gradual cooling. It is mainly the rate of change that distinguishes it. If it weren't for industrial emissions, the earth would still be cooling very slowly.

As for how to separate them, that would get into complex science and statistics that is beyond this forum. Given the (only) 90% certainty, there would not be a definite breakdown into various causes. However it would be a reasonable simplification to attribute all of the recent increase in temperature to AGW. That is, the upwards trend, but not the minor year to year variation about that trend.

Grendel to Muso....  until you take everything into consideration at once and come out with some sense or proof.

You are all over the shop.

Soren wrote on Nov 27^th, 2008 at 4:28pm:



Soren/ Grendel,

Let's take some time out from being adversarial. What I thought was obvious is apparently not so obvious. My wife tells me that I'm the world's worst 'teacher'.

It just occurred to me that even FD missed the point I made about solar irradiance. I obviously did not explain myself well enough. When you look at the solar irradiance measurements and compare against global temperature increase and global CO2 increase,  there is a significant mismatch for the last 50 years or so.

What started off as a reasonably good correlation between solar irradiance and global temperature started to become adrift in a major way from (around) 50 years ago onwards.

The major driver of global temperature for the last 50 years has obviously not been the sun. The secondary natural driver is major volcanic activity, which actually works in reverse. Again, we can show that it isn't due to volcanoes. (I can explain in detail if you like)

It really is as simple as that. (isn't it?)

FD - do you understand that now?

Maybe I should explain that the measurement of Solar Irradiance in Low Earth Orbit includes such factors as solar activity and orbital distance from the sun. You could say that it's an empirical parameter.

The actual distance of the Earth from the sun has a very significant effect on irradiance. That's why we get a slight peak in irradiance in January and a slight dip around July. The actual irradiance level varies as the cube of the distance.

Currently the Earth is closest to the sun in January (Perihelion) and furthest away in July (aphelion).

If you look at the CO2 graph from Mauna Loa, you'll also see seasonal 
variations, largely due to the same effect. Temperature affects global CO2 on a seasonal basis. Every year we get a confirmation of this 'equilibrium'* between temperature and CO2.

Grendel - remember when I asked you that question previously and you didn't answer?  Here's your answer. 

* It's not a true equilibrium by the way. For CO2 concentration there is a lag of about 3-4 months in the annual cycle. The annual peak for CO2 appears around April each year.

Grendel wrote on Nov 27^th, 2008 at 5:02pm:


It's more useful if you think of it as a whodunnit. The crime is increasing atmospheric CO2 levels and increasing global mean temperatures.

The standard should be 'beyond reasonable doubt'. Let me try to find a graph that illustrates the contributions to Global Warming.