Temperature data sets confuse me. When I look at satellite based weather data, I draw one conclusion. When I look at land/sea surface based data I draw different conclusions…and so many experts say both data sets are right.
And the sets keep changing. The sudden rapid cooling scientists saw between 1940 and the mid 1970’s when we were worrying about global cooling in 1974 no longer exists in official temperature records. The very warm weather in the 1930’s is less warm. Throw in a bit of Climategate chicanery and I believe I have some justification for my confusion.
Who would have thought the temperature of the world in 1940 was subject to so much interpretation? Were we guessing in 1940 or 1975? Are we guessing now?
A few years ago NASA world surface temperature data sets went back to 1866, now they begin in 1880. Why NASA made this change is beyond me…but I do know 1877 and 1878 were very warm years in the old data set…and just about everybody in the Climate game likes to cherry pick data.
There are four main places to go for Satellite based Tropospheric data sets. NASA’s GISStemp, the Hadley Center’s HadCRU in the UK, Remote Sensing Systems’ RSS in California, and the University of Alabama, Huntsville’s UAH.
GISStemp and HadCRU combine surface and Tropospheric data together, UAH and RSS only use Satellite data. All give similar but different interpretations to the same data. UAH and RSS insist 1998 was the warmest year while NASA and Hadley both like more recent years, like 2005 and 2010.
Generally surface data sets and satellite data sets produce similar results, one exception appears to be 1998, a year that featured an El Nino. In 1998, Satellite data was much warmer than surface data. I suspect this is because the Oceans are a particular problem for surface data sets. The best ocean surface data comes from floating buoys. Relatively few data points and the data points move around with the ocean currents.
I like Satellite data, there is just too much SWAG in surface data. Many surface data sets appear to demonstrate that global warming appears has continued into the 21st century. Satellite data sets peaked in 1998, cooled slightly for several years before peaking again in 2010. So far 2012 has been a fairly cool year….just a bit below the average of the last 32 years.
Is it warmer in 2012 than in 1998 or 1877 and does it really matter when trying to predict world climate centuries into the future?