The predicate for the theory of man-made global warming (AGW) is that temperatures are rising, and at an accelerated rate due to man-made greenhouse gases, most particularly, CO2. The most infamous proof of that predicate was the Mann Hockey Stick chart which extended back a thousand years to the present time. The chart, shows a nearly flat temperature line for the first 900 or so years after which time it begins to head North, indicating an unprecedented increase in global temperatures that coincided with a measured increase in atmospheric CO2.
MANN HOCKEY STICK CHART
While the proponents of this chart still are peer reviewing each other’s work and pronouncing it valid research, even the IPCC, which featured it in earlier reports, dropped it from the most recent (2007) report.
Climategate (released CRU email) has shown that leading suppliers of ground station temperature reports, have been manipulating the data to support their contention that these days are really unusual times. This is not news to the Skeptics. But it is nice to have it confirmed by the emails from the Climate Research Unit (CRU).
My contention is that the only global temperature record that can legitimately be used to conclude whether global temperatures are rising, falling, or holding steady is the satellite data produced by UAHuntsville. The satellite data has been available since late 1978. The data collected is from most of the globe (oceans included, of course) which is vastly superior to the data assembled for the ground stations. But my guess is that, perhaps 50 or more years are needed to get a real understanding of the data global temperature trends.
At one time there were some issues with the UAH data as the satellites tended to drift in orbit and the data derived needed some corrections. But the UAH now uses new satellites. Jeff Id, wrote as follows on the new accuracy of the UAH measurement:
The new AQUA satellite used in UAH has a station keeping thruster which keeps the measurement time of each gridcell constant for years at a time. The thing I think some miss about this is that the huge massive corrections which must be implemented over a day are suddenly the same correction value from day to day – no change. Therefore errors in corrections no longer create artificial trends. We’ve got our first high accuracy global trend measurement –ever.
Jeff Id also presented these charts of the data provided by UAH:
The temperature according to UAH over the period of their satellite measurements -1978 to 2010 yields an global temperature increase of 0.1258degrees C which equates to 0.0562 degrees C per decade.
Recently the global temperature has taken a turn downward. The UAH chart since 2002 is shown below- the time since UAH began using the Aqua Satellites.
Looking at this short interval, since June 2002, the global temperature has declined by 0.1677degrees C which would work out to be 0.2292 degrees C decrease over a decade.
To read Jeff Id’s complete report, click here.
What can we say about UAH temperature data?
- It is very accurate,
- It is global in a real sense,
- It is not subject to manipulation,
- Its history is not yet long enough to derive real trends.
And that is more than we can say about the CRU and GISS data.
I strongly recommend that on UAH temperature data be used for global warming legislative decisions. I will talk more about why CRU and GISS should not be used in future postings.