Jmister Posted September 13, 2013 Share Posted September 13, 2013 I don't claim to take a side on the issue of climate change. I try to keep as objective as humanly possible. That being said, I came across this commentary in a journal. It compares the hindcast global temperature from the CMIP5 models with that of instrumental temperature records from HadCRUT4 to show that the simulated temperature rise is (statistically significantly) higher than the instrumental temperature. I know we have quite the divide of people in this forum, and I was hoping to get some feedback from both sides. Is this a fair comparison? Is the HadCRUT4 dataset a "cooler" representation of global temperature than others? title and abstract: Overestimated global warming over the past 20 years Recent observed global warming is significantly less than that simulated by climate models. This difference might be explained by some combination of errors in external forcing, model response and internal climate variability. Source: http://www.see.ed.ac.uk/~shs/Climate%20change/Climate%20model%20results/over%20estimate.pdf I'm not trying to take sides or make enemies! I just want to know the real facts of the matter. Thanks! Link to comment Share on other sites More sharing options...
nflwxman Posted September 13, 2013 Share Posted September 13, 2013 I don't claim to take a side on the issue of climate change. I try to keep as objective as humanly possible. That being said, I came across this commentary in a journal. It compares the hindcast global temperature from the CMIP5 models with that of instrumental temperature records from HadCRUT4 to show that the simulated temperature rise is (statistically significantly) higher than the instrumental temperature. I know we have quite the divide of people in this forum, and I was hoping to get some feedback from both sides. Is this a fair comparison? Is the HadCRUT4 dataset a "cooler" representation of global temperature than others? title and abstract: Overestimated global warming over the past 20 years Recent observed global warming is significantly less than that simulated by climate models. This difference might be explained by some combination of errors in external forcing, model response and internal climate variability. Source: http://www.see.ed.ac.uk/~shs/Climate%20change/Climate%20model%20results/over%20estimate.pdf I'm not trying to take sides or make enemies! I just want to know the real facts of the matter. Thanks! I read through the abstract and they looked at the typical suspects for the difference between modeled and observed warming. Perhaps I am reading it wrong, it appears that the authors suggest a mixture of natural oceanic variability (ENSO), solar output, stratospheric WV, and increased aerosols account for most of the discrepancy. Though, I must admit, aerosol concentration is a tough element of the climate system to estimate due to lack of worldwide measurement. Do you have the full paper handy or just the commentary? Link to comment Share on other sites More sharing options...
ORH_wxman Posted September 13, 2013 Share Posted September 13, 2013 We actually briefly discussed that paper in this thread: http://www.americanwx.com/bb/index.php/topic/39853-the-pdo-and-decadal-global-temperatures-in-climate-change/page-3 Hadcrut4's anomalies are lower than GISS because they use a 1961-1990 baseline vs 1951-1980 like GISS. The trend on both of the datasets is pretty much identical though in the past 20 years (0.13C per decade for GISS and 0.12C for Hadcrut)...Hadcrut4 is a recent peer reviewed dataset upgraded from Hadcrut3. Link to comment Share on other sites More sharing options...
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