By JR on Wednesday, January 27, 2016
New Warmist claim hot off the press
Mann, Rahmstorf & Co. had a new article published on 25th and the Daily Mail had their take on it on 26th. So I am a slow-poke in getting to it on 27th. It's basically another "Warmest year" claim that ignores statistical significance and fails to note that their temperature changes go both down and up relative to the average. In other words the changes indicate a temperature plateau rather than systematic warming. Anyway, I reproduce below both the DM article and the academic journal abstract. You will see that the whole thing is just another modelling exercise -- and you can get whatever answer you want out of models. You can get everything but an accurate prediction of actual temperatures
Since the start of the new millennium, the world has experienced a succession of the warmest years on record.
Now scientists say it is extremely likely these unprecedented high global temperatures have been caused by human emissions from the burning of fossil fuels such as coal and oil.
It comes just days after Nasa confirmed 2015 was the hottest year on record, with temperatures rising 1.8°F (1°C) above those seen before industrialisation.
The latest study claims it is 'extremely unlikely' that 13 of the 15 hottest years to have occurred since records began 150 years ago would happen since 2000 due to natural variability.
This, they said, suggests it is 600 to 130,000 times more likely than not that human activities and their influence on the climate have caused this record breaking run of hot weather.
The dataset produced by the Met Office Hadley Centre and the Climate Research Unit at the University of East Anglia found global mean temperatures reached 1°C above pre-industrial levels for the first time.
It said the year's average global temperature was the highest ever recorded.
Professor Stefam Rahmstorf, a physicist at the Postdam Institute for Climate Impact Research, in Germany, said: 'Natural climate variations just can't explain the observed recent global heat records, but man-made global warming can.
'It has led to unprecedented local heat waves across the world - sadly resulting in loss of life and aggravating droughts and wildfires.
'The risk of heat extremes has been multiplied due to our interference with the Earth system, as our data analysis shows.'
The researchers, whose work is published in the journal Scienific reports, analysed real world measurements and combined them with computer simulations of the global climate.
This, they continued, allowed them to work out how the climate may have behaved if there had not been any human greenhouse gas emissions.
The results show the odds of human activity being behind the recent spate of record breaking annual global temperatures are far higher than previously believed.
The Likelihood of Recent Record Warmth
Michael E. Mann, Stefan Rahmstorf, Byron A. Steinman, Martin Tingley & Sonya K. Miller
2014 was nominally the warmest year on record for both the globe and northern hemisphere based on historical records spanning the past one and a half centuries1,2. It was the latest in a recent run of record temperatures spanning the past decade and a half. Press accounts reported odds as low as one-in-650 million that the observed run of global temperature records would be expected to occur in the absence of human-caused global warming. Press reports notwithstanding, the question of how likely observed temperature records may have have been both with and without human influence is interesting in its own right. Here we attempt to address that question using a semi-empirical approach that combines the latest (CMIP53) climate model simulations with observations of global and hemispheric mean temperature. We find that individual record years and the observed runs of record-setting temperatures were extremely unlikely to have occurred in the absence of human-caused climate change, though not nearly as unlikely as press reports have suggested. These same record temperatures were, by contrast, quite likely to have occurred in the presence of anthropogenic climate forcing.
Scientific Reports 6, Article number: 19831 (2016) doi:10.1038/srep19831