by Dana Nuccitelli, Skeptical Science, January 30, 2013
Conservative Climate Projections
Sea Level Rise
"The satellite-based linear trend 1993–2011 is 3.2 ± 0.5 mm yr-1, which is 60% faster than the best IPCC estimate of 2.0 mm yr-1 for the same interval"
Arctic Sea Ice Decline
"The IPCC projections are based on estimates that CO2 emissions in China increased at an annual rate of about 3–4% during the past 10 years (IPCC, 2007a; IEA, 2007), but a subsequent province-based inventory concluded that emissions actually increased at a higher rate of about 10–11% (Auffhammer & Carson, 2008)....Emissions from a number of other developed countries were also higher than agreed-to targets."
Permafrost Melt and Carbon Feedback
Other Climate Impacts
"Erring on the Side of Least Drama" (ESLD) to Avoid Alarmism
"Our analysis of the available studies suggests that if a bias is operative in the work of climate scientists, it is in the direction of under-predicting, rather than over-predicting, the rate and extent of anthropogenic climate change."
"The frequent attacks on Stephen Schneider—as well as attacks on other climate scientists such as Benjamin Santer and Michael Mann—suggests that one possible reason why scientists may have underestimated the threat of anthropogenic warming is the fear that if they don’t, they will be accused by contrarians (as was Schneider) of being alarmist fear-mongers. That is to say, pressure from skeptics and contrarians and the risk of being accused of alarmism may have caused scientists to understate their results."
The Ozone Example
"In the aftermath of the unrealized 1992 Arctic ozone hole prediction, NASA scientists were severely criticized in the conservative press for crying wolf, causing unnecessary panic, and acting according to emotional imperatives or an environmental agenda instead of according to the dictates of scientific objectivity."
Other Causes of ESLD
The Dangers of ESLD
- in order to avoid accusations of "alarmism" from climate contrarians;
- because scientists are skeptical by nature whereas climate impacts are dramatic;
- and because dramatic claims open scientists to criticism from their peers.
"If climate scientists and assessors are erring on the side of least drama in their predictions, then they are not preparing policymakers and the public for the worst, because they are underpredicting what the worst outcomes might be."
http://www.skepticalscience.com/climate-scientists-esld.html"Our hypothesis of ESLD is not meant as a criticism of scientists. The culture of science has in most respects served humanity very well. Rather, ESLD provides a context for interpreting scientists’ assessments of risk-laden situations, a challenge faced by the public and policy-makers. In attempting to avoid drama, the scientific community may be biasing its own work—a bias that needs to be appreciated because it could prevent the full recognition, articulation, and acknowledgment of dramatic natural phenomena that may, in fact, be occurring. After all, some phenomena in nature are dramatic. If the drama arises primarily from social, political, or economic impacts, then it is crucial that the associated risk be understood fully, and not discounted."