from the Guardian….amp.theguardian.com/…
in their new book : Discerning Experts: The Practices of Scientific Assessment for Environmental Policy, Dale Jamieson, Michael Oppenheimer and Naomi Oreskes wrestle with one of the more aggravating trends we see in climate research: Why do we seem to get more and more data that show much more dire implications for the Climate Crisis than the large ICPP studies predict?
While climate skeptics and deniers often accuse scientists of exaggerating the threats associated with the climate crisis, the available evidence suggests the opposite. By and large, scientists have either been right in their assessments, or have been unduly conservative. We noticed a clear pattern of underestimation of certain key climate indicators, and therefore underestimation of the threat of climate disruption. When new observations of the climate system have provided more or better data, or permitted us to re-evaluate earlier conclusions, the findings for ice extent, sea level rise and ocean temperature have generally been worse than previously thought.
I must admit that I wondered about this —I saw a report a while back where a climatologist said that she has yet to go to a conference where the news was better than any one had predicted...
The authors use this example to help explain why we see so so much underestimation:
How does the pressure for univocality lead to underestimation? Consider a case in which most scientists think that the correct answer to a question is in the range one to 10, but some believe that it could be as high as 100. In this case, everyone will agree that it is at least one to 10, but not everyone will agree that it could be as high as 100. Therefore, the area of agreement is one to 10, and this will be reported as the consensus view. Wherever there is a range of possible outcomes that includes a long, high-end tail of probability, the area of overlap will lie at or near the low end.
This has direct implications
We are not suggesting that every example of under-estimation is caused by the factors we observed in our work, nor that the demand for consensus always leads to underestimation. But we found that this pattern occurred in all of the cases that we studied. We also found that the institutional aspects of assessment, including who the authors are and how they are chosen, how the substance is divided into chapters, and guidance emphasizing consensus, also generally tilt in favor of scientific conservatism. [my emphasis]
All of which goes a long way to explaining the disconnect between broad ICPP type studies. with their consensus orientation — the far more conservative viewpoint usually based on oil based nations insisting on far less strident language and what many many individual studies are showing
they close with a summation that many of us have recognized
For political leaders and business people, we think it is important for you to know that it is extremely unlikely that scientists are exaggerating the threat of the climate crisis. It is far more likely that things are worse than scientists have said. We have already seen that the impacts of increased greenhouse gases in the atmosphere are unfolding more rapidly than scientists predicted. There is a high likelihood that they will continue to do so, and that the IPCC estimates – that emissions must be rapidly reduced, if not entirely eliminated, by 2050 – may well be optimistic. The fact that this conclusion is hard to swallow does not make it untrue.
And for ordinary citizens, it is important to recognize that scientists have done their job. It is now up to us to force our leaders to act upon what we know, before it is too late. [my emphasis]
