Looking at this title, what do you imagine my implications to be?
By “wrong” do you think I mean “global warming turns out to be natural/nonexistent/a global conspiracy”?
A very interesting sociological phenomenon……In the popular media, we hear so much from people who think that the dangers of climate change have been overstated by the IPCC, and virtually nothing from those who think the dangers have been understated. In fact, I can’t remember ever reading the latter viewpoint in the popular press, while the former presents itself almost weekly on the editorial page.
See, for example, this gem. I haven’t even looked into the quoted statistics (as they’re all from the Science and Public Policy Institute, truly the epitome of credibility….) and already I can guess what sorts of tricks are being played. Picking two convenient years from the last decade, calculating a linear regression, extrapolating that to rate of change per century, comparing that to the IPCC’s worst-case future predictions, and saying “oh look, the IPCC is wrong!” Works for temperature, CO2 concentration, and sea levels.
When the public reads “the IPCC is wrong” enough times in this context, they start to unconsciously equate it with “the IPCC is overestimating the dangers of global warming”. That’s my knee-jerk reaction, too.
I wasn’t even aware of this phenomenon, however, until I read an as-yet-unpublished poll of scientists’ opinions on the IPCC. The abstract says that “there is not a universal agreement among climate scientists about climate science as represented in the IPCC’s WG1″, “there remains substantial disagreement about the magnitude of [climate change's] impacts”, and “there are….a significant number of climate scientists who disagree with the IPCC WG1 perspective”.
Reading this abstract, it sure sounds like the report found a lot of scientists who think the IPCC has overstated global warming. However, the report found that the IPCC perspective was the mean opinion of climate scientists, and there was a fairly equal minority on each side. 18% thought the IPCC was overestimating, 17% thought the IPCC was underestimating, and the rest thought it was about right.
I am in no way endorsing the findings of this study – as, not being peer reviewed, it wouldn’t pass our comment policy. I am simply using it as an example of how “significant disagreement with the IPCC” really has to be spelled out. The public has been so indoctrinated with the idea that “the IPCC is wrong” equates to “the IPCC is overestimating”, while in reality, it can mean exactly the opposite too.
(To be honest, I’m quite glad that this report wasn’t published without changes to the abstract, because it would be all-too-easy for WUWT et al to take the abstract quotes out of context and parade around saying “look the IPCC is wrong!” A furious blogging storm would begin. We’d be hearing the quotes out of context for years. Peter Sinclair would have to make a video about it.)
There certainly is a chance that the IPCC is overestimating or underestimating the impacts of global warming. In particular, the lag time between collecting data for a publication and the release of the IPCC report could increase error. Gwynne Dyer, in his book Climate Wars (review coming soon), estimated that “most of the data that formed the basis for the IPCC’s 2007 report actually refer to 2002 and earlier.” As few things become out of date faster than climatology data (for example, my chem notes still say that CO2 is at 350 ppm), what we’ve learned in the past 7 or 8 years would likely alter the findings of the IPCC. If we were somehow able to produce a new report instantly, it would interesting to see how the new data made it differ from the AR4. (Does anyone know of a good resource which compared the TAR to the AR4 in this way?)
Another way that the IPCC may seem to underestimate global warming is really very tricky. A lot of their future projections, understandably, are unable to model all the aspects of climate change. Many feedbacks cannot be modelled, especially the release of methane hydrates, so greenhouse gas levels don’t include such feedback processes. The collapse of ice sheets cannot be modelled, so sea-level predictions only account for thermal expansion.
Most of what they can’t model would make the projections a lot worse, but they have no way of knowing how much worse, so they just include, “not including uncertainty in carbon cycle feedbacks”. If you weren’t looking for this disclaimer, you wouldn’t know it was there. And try finding it in the summary for policymakers, which is the only part of the report most people will read.
Gwynne Dyer says it best:
“Leaving the biggest potential feedbacks – methane and carbon dioxide release from thawing permafrost in the higher latitudes, and carbon dioxide release from warming oceans – out of the climate change scenarios that the IPCC generates is defensible in scientific terms, for the did genuinely lack the ability to model them accurately. But, in a report intended for non-scientists, this omission ought to have been highlighted in warning yellow, not buried in the footnotes.”
Does anyone know of a peer-reviewed source which has attempted to include such feedbacks in future projections? In an interview with Dyer, Dennis Bushnell from NASA mentions a rough estimate which calculated a 6 to 12 C warming by 2100 if feedbacks were included. However, I can’t seem to track this down….
The IPCC may seem extreme in some circles, as it supports the drastic notions that the Earth is warming and carbon dioxide is a greenhouse gas. This basic support for the mechanisms of anthropogenic climate change has led the IPCC to be boxed in to the “climate change is real” camp in the general media, which faces off with an omnipresent “climate change is fake” camp. However, we must realize that there is also a camp that says “climate change is real and even worse than the IPCC estimates”. The IPCC, really, is the median scientific opinion – the “truth somewhere between the two extremes” that the public so wholeheartedly supports. Newspapers obviously aren’t too good at averaging.