In my last post I created a reconstruction of global temperature over 350 years which I show below:
And as I said in the article, I was confused why the UAH 6 (red) had not warmed as much as the Central England Temperature (CET). I thought about it and it seemed to me that there was some factor affecting CET which in some way was being averaged out by the far more global UAH, which implied that some parts of the world were more like CET and had been warmer and some must have been a lot cooler so that the average overall was lower. At first I assumed this might be a northern-southern hemisphere. So, I played around with a few graphs on WoodForTrees.org and eventually produced this:
Here we can see that the actual global temperature from UAH is the lowest of the bunch, which is not that different from HADCRUT global south which is mostly ocean, next is Hadcrut north which is more land and the highest is CRUTEM north which is land only from the northern hemisphere.
If we now plot this back on the original CET graph we can see where the CET warming is coming from:
It’s very clear from this the discrepancy between CET and global satellite UAH is because it is northern hemisphere land. This also fits in with other evidence such as Arctic ice levels dropping whilst Antarctic increased.
So, let’s take a closer look at what is happening at sea. Below are the sea temperatures for north (blue) & south (green) sandwiched between UAH (purple) at the bottom and CRUTEM Northern land temps (red) at the top:
With every other series being lower than GISS, this tells me that the main discrepancy between GISS and the real global temperature shown in UAH comes from land based measurements. And in order for the landbased measurements to cause GISS to be much higher than the satellite average, it is necessary that GISS is recording from areas that are warming faster than most of the land. Why is this?
Of course I could just say it’s intentional, or Urban heating. But let’s for a moment ignore the obvious and look at this map of GISS temperature stations:-
Very few a located in the centre of Africa and this lack of mid-continent sensors is repeated in other places like S.America (Grey means lack of sensors):
The reason GISS is showing too high a temperature, is because the majority of its sensors are located near the coast where temperatures have been warming, which means that coastal warming must be balanced by central-continent cooling.
From the above and other information we have the following evidence:
- Coastal warming must be offset by mid-continent cooling (at least outside the poles)
- Greenland surface ice has been increasing
- Antarctic ice has been increasing
Thus it seems that in the last 20-30 years we have seen something that has caused coastal warming and mid-continent cooling (or at least cooler than coasts).
Usually, the sea is colder than the land and as such cooling winds move from the sea to the land and cool the coast. One way (not involving fraud and/or Urban heating) for the coastal areas to have warmed excessively, would be a drop in the intensity of winds that would normally cool the coasts.
This in turn suggests that inland continental areas are either:
- Becoming cloudier – perhaps because of pollution directly blocking sunlight or acting as cloud nuclei. (This would reduce wind speed and reduce temperature)
- That there is less moisture (because moist air rises. But this would mean inland temperatures would be warmer as evaporation is a major coolant.
Thus it is possible to suggest a further hypothesis (assuming we aren’t blaming Urban heating or fraud):
That something (e.g. pollution, dust or some other effect like solar activity) is increasing the level of cooling clouds in the centre of continents. This in turn is reducing the strength of on-shore breezes and leading to higher coastal temperatures. Thus coastal warming and inland cooling is leading to the over-reporting of global temperatures by land-based measurements which are predominantly on the coastal areas of continents.