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New Statistical Analysis Suggests Probability That Climate Change Is Natural Is Very Slim

A key diagram from a new paper published in Climate Dynamics by Professor Shaun Lovejoy from McGill University. Lovejoy claims that a statistical analysis of temperature records contradicts claims that global warming is natural in origin and that computer climate models are wrong. “In this paper we have argued that since ≈ 1880, anthropogenic warming has dominated the natural variability to such an extent that straightforward empirical estimates of the total warming can be made,” Lovejoy's paper concludes. Lovejoy equated the forcing due to increased CO2 with anthropogenic forcing arguing that that method was justified “because we showed that over a wide range of scales, the residuals have nearly the same statistics as the preindustrial multiproxies.” The main uncertainty is the time lag between climate forcing and temperature response, says Lovejoy. The brown line is the underlying human driven temperature change and the purple line represents the residual natural variability superimposed upon it. Courtesy: Shaun Lovejoy and Springer. See our report here.  

 

 

Call To Accelerate Move Away From Fossil Fuels Accompanies Release Of IPCC WGIII Report

The third part of the latest (AR5) assessment of the United Nations Intergovernmental Panel on Climate Change (IPCC) calls for a move away from fossil fuels. The so called Working Group III (WGIII) report, focusing on mitigation and entitled "Climate Change Mitigation", follows hot on the heels of publication of the WGII report  "Climate Change 2014: Impacts, Adaptation, and Vulnerability" last month. “Nobody on this planet is going to be untouched by the impacts of climate change,” IPCC chairman Rajendra Pachauri warned at the launch of the WGII report. These publications come in the wake of the WGI report on the underlying science of climate change in September 2013. See here.

 

 

Study Reveals Greenland Ice Loss Accelerating As Last Stable Ice Sheet Becomes Unstable

 

Major outlet glaciers in northeast Greenland disintegrate into the ocean. This previously stable region of the Greenland ice sheet is found to be undergoing dynamic thinning — mass loss caused by meltwater runoff — due to regional warming, as reported in an article published online in Nature Climate Change. These findings suggest that Greenland’s contribution to sea-level rise was previously underestimated and needs to be accounted for in future projections. The Greenland ice sheet, and particularly glaciers in the southeast and northwest, has been a significant contributor to global sea-level rise over the past 20 years. However, the northeast ice stream, which drains 16% of the ice sheet, was not thought to contribute. Shfaqat Khan and colleagues use surface elevation measurements of the entire Greenland ice sheet over the period 1978–2012 to estimate changes in ice thickness near the coast. They find that the northeast ice stream was stable until around 2003, when increased air temperatures caused dynamic thinning to commence. Reduced sea ice at the outlet where the glacier meets the ocean, due to warm summers during 2002–2004, allowed icebergs to break off causing the ice stream to accelerate towards the sea. The team found that the northeast Greenland ice stream basin has been losing more than 10 gigatonnes of ice mass per year since 2006, and this is expected to continue in the near future due to the steady increase in glacier speed and ice loss. Full story here. Image courtesy: Finn Bo Madsen  

 

 

Marine Sediment Core Research Links Sun And North Atlantic Blocking With Little Ice Age

The two black dots marked "RAPiD" on this sea surface temperature chart show the location of two sediment cores that have been used by researchers to study historic salinity and temperature in the North Atlantic. In research just published in Nature Geoscience, the researchers conclude that low solar activity and North Atlantic blocking patterns may have been responsible for the Little Ice Age. Report here.

 

 

 

 

 

 

March Global Average Tropospheric Temperature Anomaly As Measured By Satellite +0.17C

Global temperature data released by the University of Alabama in Huntsville shows that the temperature anomaly for March 2014 for the lower troposphere was +0.17oC above the long term average, unchanged from February 2014, down on the January figure of +0.29oC and slightly below the March 2013 figure of +0.20oC. See our report here. Image courtesy: Dr Roy Spencer, UAH.