Dr. Andrew Shepherd, an IPCC author who works at the Centre for Polar Observation and Modelling, said the UOB study used calculations that appeared to have overlooked shifts in snowfall, noting that the "new estimates of ice loss computed (from the thinning of the ice) are far too high, because the glaciers in this sector just haven't speeded up that much."
Global temperature change observed over the last hundred years or so is well within the natural variability of the last 8,000 years, according to a new paper by a former Intergovernmental Panel On Climate Change (IPCC) lead author.
Dr. Philip Lloyd, a South Africa-based physicist and climate researcher, examined ice core-based temperature data going back 8,000 years to gain perspective on the magnitude of global temperature changes over the 20th Century.
Georgia Institute of Technology's Dr. Judith Curry on April 15, 2015 at The House of Representatives Committee on Science, Space and Technology Hearing on the President’s UN Climate Pledge: 'Recent data and research supports the importance of natural climate variability and calls into question the conclusion that humans are the dominant cause of recent climate change. This includes:
The slow down in global warming since 1998
Reduced estimates of the sensitivity of climate to carbon dioxide
Climate models that are predicting much more warming than has been observed so far in the 21st century
We have made some questionable choices in defining the problem of climate change and its solution:
The definition of ‘dangerous’ climate change is ambiguous, and hypothesized catastrophic tipping points are regarded as very or extremely unlikely in the 21st century
Efforts to link dangerous impacts of extreme weather events to human-caused warming are misleading and unsupported by evidence.
According to the 1990 IPCC Report, an additional 0.5C global warming would need to be observed before natural variability could be distinguished with high confidence from an "enhanced greenhouse effect" due to man-made emissions. However, as an article today at Reason.com points out,
"...enhanced greenhouse warming above the noise of natural climate variability would not yet have crossed over the benchmark (+0.5°C) set by the IPCC back in 1990. Interesting."
Satellite data indicates only ~0.2C warming since 1990, considerably short of the 0.5C threshold the IPCC set for itself in 1990 to determine whether additional global warming was within natural variability.
The Max Planck study suggests “that aerosol radiative forcing is less negative and more certain than is commonly believed.” In layman’s terms, aerosols are offsetting less global warming than was previously thought. And if aerosols aren’t causing as much cooling, it must mean carbon dioxide must be causing less warming than climate models predict.