There are a remarkable number of myths and misconceptions about climate science. In a set of upcoming posts in the coming weeks starting with this one, I overview these “errors” in the communication of climate science among scientists and to the policymakers, the media and the public.
Misconception #1: The global average surface temperature trend is a robust metric to assess climate change.
As just one example to refute this claim, I refer to a new excellent post by Judy Curry
Separating natural and anthropogenically-forced decadal climate variability
where she refers to the paper
Solomon, Amy, and Coauthors, 2011: Distinguishing the Roles of Natural and Anthropogenically Forced Decadal Climate Variability. Bull. Amer. Meteor. Soc., 92, 141–156. doi: 10.1175/2010BAMS2962.1
which states
“….over the course of the next 10–30 years the magnitude of natural decadal variations may rival that of anthropogenically forced climate change on regional scales…”
The authors may not realize the significance of their statement (although Judy does). However, this focus on regional scales, along with the recognition of the importance of regional circulation patterns, illustrates how the 2007 and earlier IPCC reports failed by focusing on a global average radiative forcing, as represented by an annual global average surface temperature trend.
Work that we have written about further illustrates the failure of the global average surface temperature trend as a useful climate metric with respect to climate impacts, such as drought and floods, that matter to the environment and society. The erroneous use of this metric by high level scientists and policymakers to communicate risks from climate is misleading policymakers.
One example is illustrated by the article
Pielke, R.A. Sr., H.J. Schellnhuber, and D. Sahagian, 2003: Non-linearities in the Earth system. Global Change Newsletter, No. 55, 11-15.
What is also interesting about this article is that Hans Schellnhuber was Chief Government Advisor on Climate and Related Issues during Germany’s EU Council Presidency and G8 Presidency and has other high level political positions (e.g. see).
Unfortunately in his political role, he has ignored the significance of the statements we reported on in our co-authored article. Instead, in his poltical role, he has focused on the global average radiative forcing as represented by the global annual average surface temperature trend as the primary metric to encourage energy policy.
He has done this not just in Germany and the EU, but also in the USA; e.g. see the news article Four Degrees of Devastation by Stephen Leahy on October 9 2009), where he was reported as saying
“Schellnhuber ….. briefed U.S. officials from the Barack Obama administration….[and] told them that the U.S. must reduce its emissions from its current 20 tonnes of carbon per person average to zero tonnes per person by 2020 to have an even chance of stabilising the climate around two degrees C. “
However, as Schellnhuber agreed with in our earlier 2003 article that he co-authored
“…climate is not the long term average of weather statistics, but involves the non-linear interactions between the atmosphere, oceans, continental ice, and land surface processes, including vegetation, on all time scales.”
In the context of Judy Curry’s post and the Solomon et al 2011 article, we (with Hans Schellnhuber as co-author) write in our 2003 article
“…irregular variations of the North Atlantic Oscillation, the El Niño Southern Oscillation, and the Pacific Decadal Oscillation are well documented…. While the reasons for the temporal changes in these climate features are not fully understood, the close coupling between the ocean and the atmosphere has clearly been demonstrated by observations and modelling. Such temporal variations in the Earth System may partly explain the large changes observed in some regional hydrologic and ecological systems during the 20th century. For example, an abrupt change in the annual outflows from African equatorial lakes occurred in 1961, followed by a slow downward trend…”
Thus
“…since none of the general circulation models (GCMs) used to project climate change over the next hundred years include all of the important forcings and feedbacks, they should be considered as sensitivity studies rather than forecasts…”
The recognition of the complexity of the climate system is becoming better recognized by the IPCC community, but it is way overdue. Hans Schellnhuber, who I respect as a colleague, should revisit his viewpoint that was expressed in our 2003 paper. His 2003 view is a robust characterization of climate science,while his more recent political pronouncements are not.
The new Solomon et al paper and posts by Judy Curry should alert Hans that in the last few years he has been focusing his policy recommendations on a misconception of the real world behavior of the climate system.
As a result of inaccurate communication of climate science by senior climate scientists who have had a different view in the past (such as Hans), policymakers are making decisions with seriously flawed climate science information.
Climate Science: Roger Pielke Sr. 