Skeptical website Bishop Hill Analysis: ‘Schmidt and his colleagues are looking at the hiatus in surface temperature rises and considers why the CMIP5 ensemble all got it so wrong. In their new paper they explain that the reason for this is not – as wild-eyed readers at BH might think – that the models are wonky. In fact it’s all down to an incredible, incredible coincidence’
NASA’s Gavin Schmidt’s paper: ‘Here we argue that a combination of factors, by coincidence, conspired to dampen warming trends in the real world after about 1992. CMIP5 model simulations were based on historical estimates of external influences on the climate only to 2000 or 2005, and used scenarios (Representative Concentration Pathways, or RCPs) thereafter.
Bishop Hill Analysis: ‘Apparently, if you go back and rework all the forcings, taking into account new data estimates (add half a bottle of post-hoc figures) and ‘reanalyses’ of old data (add a tablespoon of computer simulation) you can bridge the gap and explain away the pause.’
NASA’s Schmidt’s paper: ‘Nevertheless, attributing climate trends over relatively short periods, such as 10 to 15 years, will always be problematic, and it is inherently unsatisfying to find model–data agreement only with the benefit of hindsight.’
Bishop Hill Analysis: ‘So, with the benefit of hindsight, the climate modellers can fit their square peg into a round hole. It wasn’t that the models were running too hot, it was just that nature has got it in for climate modellers.’
Climate Depot Analysis: ‘There have been at least
nine ten separate explanations for the standstill in global warming’ – 1) Low Solar Activity; 2) Oceans Ate Warming; 3) Chinese Coal Use; 4) Montreal Protocol; 5) Readjusted past temps to claim ‘pause’ never existed 6) Volcanoes 7) Decline in Water Vapor 8) Pacific Trade Winds 9) ‘Stadium Waves’ 10) ‘Coincidence’
Welcome to the world of ‘settled science’. With the latest study now placing blame on Sun for the ‘pause’ in global temperatures, that means there have been at least
five seven eight nine ten separate explanations to attempt to explain the standstill in global warming. There is seemingly no end to warmists’ attempts to explain the global warming standstill.
Update Feb. 28, 2014: Der Spiegel On 15-Year Pause: ‘Biggest Mystery In Climate Science’: ‘Climate models had never expected the pause: Only 3 of 114 climate simulations were able to reproduce the trend of the past years, the IPCC concludes in its latest report. The reason for the deviation between models and observations is unclear.’
As blogger Tom Nelson noted: ‘If we don’t understand lack of warming post-1998, how can we understand warming pre-1998?’
3) Chinese coal caused the ‘pause’, published in the proceedings of the National Academy of Science. The study blamed Chinese coal use for the lack of global warming. Global warming proponents essentially claimed that coal use is saving us from dangerous global warming
4) The Montreal Protocol caused the ‘pause‘, which reduced CFC’s – but warming will return soon
5) The ‘pause’ never existed and presto, warmists readjusted Arctic temperatures to alter past global temperatures. See: Say What?! After years trying to ‘explain away’ the flatline/pause/standstill’ in global temperatures, warmists now readjust past temps to claim ‘pause’ never existed! – See: Presto! There was no global temperature standstill! Warmists rewrite temperature data to claim: ‘Global Warming Since 1997 Underestimated by Half’ (also see: Climatologist Dr. Judith Curry on the Cowtan & Way ‘pausebuster’: ‘Is there anything useful [in it]?’)
6) Volcanic aerosols, not pollutants, tamped down recent Earth warming, says CU study – March 2013: A team led by the University of Colorado Boulder looking for clues about why Earth did not warm as much as scientists expected between 2000 and 2010 now thinks the culprits are hiding in plain sight — dozens of volcanoes spewing sulfur dioxide. The study results essentially exonerate Asia, including India and China, two countries that are estimated to have increased their industrial sulfur dioxide emissions by about 60 percent from 2000 to 2010 through coal burning…Small amounts of sulfur dioxide emissions from Earth’s surface eventually rise 12 to 20 miles into the stratospheric aerosol layer of the atmosphere, where chemical reactions create sulfuric acid and water particles that reflect sunlight back to space, cooling the planet. Neely said previous observations suggest that increases in stratospheric aerosols since 2000 have counterbalanced as much as 25 percent of the warming scientists blame on human greenhouse gas emissions. “This new study indicates it is emissions from small to moderate volcanoes that have been slowing the warming of the planet.”
7) Contributions of Stratospheric Water Vapor to Decadal Changes in the Rate of Global Warming – 2010 Science Mag.: Stratospheric water vapor concentrations decreased by about 10% after the year 2000. Here we show that this acted to slow the rate of increase in global surface temperature over 2000–2009 by about 25% compared to that which would have occurred due only to carbon dioxide and other greenhouse gases.’
8) Update Feb. 9, 2014: New paper finds excuse #8 for the ‘pause’ in global warming: Pacific trade winds: A paper published today in Nature Climate Change adds the eighth excuse for the ‘pause’ in global warming: strengthened Pacific trade winds, which according to the authors, were “not captured [simulated] by climate models.” On the basis of those same highly-flawed climate models, the authors predict rapid global warming will resume in a decade or so when those trade winds abate.
9) Update Feb. 28, 2014 via WattsUpWithThat.com: Stadium Waves. Wyatt and Curry 2013. ‘Stadium waves’ could explain lull in global warming. In a recent paper, Marcia Wyatt and Judith Curry posited about “Stadium Waves” and climate, suggesting that the ‘stadium-wave’ signal propagates like the cheer known as “the wave” at sporting events whereby sections of sports fans seated in a circular or oval stadium stand and sit as a ‘wave’ propagates through the audience…The stadium wave periodically enhances or dampens the trend of long-term rising temperatures, which may explain the recent hiatus in rising global surface temperatures. “The stadium wave signal predicts that the current pause in global warming could extend into the 2030s,” said Wyatt, an independent scientist after having earned her Ph.D. from the University of Colorado in 2012.
10) Update: Feb. 27, 2014: A new excuse (#9) of the global warming ‘pause’ according to NASA scienitsts — ‘Coincidence!’ — ‘Coincidence, conspired to dampen warming trends’: NASA’s Gavin Schmidt & colleagues finds ‘that a combination of factors, by coincidence, conspired to dampen warming trends in the real world after about 1992’ — Latest excuse (excuse #9) for global temperature standstill mocked by skeptics: ‘Apparently, if you go back and rework all the forcings, taking into account new data estimates (add half a bottle of post-hoc figures) and ‘reanalyses’ of old data (add a tablespoon of computer simulation) you can bridge the gap and explain away the pause.’
There is a potential 11th cause of the pause as well. See:
Another cause of ‘pause’?! New Study: ‘Smell of forest pine can limit climate change’ – ‘Pine forest smell could be the smell that actually limits climate change from reaching such levels that it could become really a problem in the world’ – Smell of Pine May Save us From Climate Doom!? Study published in the journal Nature: ‘New research suggests a strong link between the powerful smell of pine trees and climate change. Scientists say they’ve found a mechanism by which these scented vapours turn into aerosols above boreal forests. These particles promote cooling by reflecting sunlight back into space and helping clouds to form’ — Cooling effect: The authors believe that this is playing a significant role in reducing the impact of rising temperatures. They argue that this effect is likely to strengthen in the future. ‘In a warmer world, photosynthesis will become faster with rising CO2, which will lead to more vegetation and more emissions of these vapours,’ said lead author, Dr Mikael Ehn, now based at the University of Helsinki. ‘This should produce more cloud droplets and this should then have a cooling impact, it should be a damping effect.’ Dr Ehn believes the vapours could have a significant impact in the medium term. ‘If you go into a pine forest and notice that pine forest smell, that could be the smell that actually limits climate change from reaching such levels that it could become really a problem in the world.’