An oped involves extreme compression, and so I thought I’d expand on why I think the initial IPCC reports so underestimated the threat. Make no mistake, the consensus in the summaries for policy makers in the first two assessments did underestimate the threat. The consensus was that permafrost would be stable for the next 100 years and also that the ice sheets would remain stable (there was even a strong sentiment at that time that the East Antarctic sheet would gain mass). Moreover, in 1990, the concept of rapid climate change was at the periphery of mainstream scientific opinion. All these things turned out to be wrong
Of course, there were scientists at that time who raised alarms about the possibility of rapid climate change, collapse of the ice sheets, and nightmare scenarios of melting permafrost, but, fairly or not, the IPCC summary for policy makers was and is taken to represent the consensus of scientific thinking.
In my opinion such documents will always take a more conservative (less dramatic) position than what scientists feel is justified. For one thing the IPCC included policy makers, most of whom were more incentivized to downplay the threats. For another, many of the national governments that were the customers for these assessments barely tolerated the exercise and gave strong signals that they didn’t want to see anything that called for dramatic action, and this being the UN, there was a strong push to present a document that as many governments as possible would accept.
And then there is the nature of science and the state of climate science at that point. There is an inherent structural lag built in to the nature of science. For instance, the 1980’s were marked by the rapid development of proxies to see past climate changes with ever more precision. By the mid-late 80’s the proxies and siting had been refined sufficiently that the GISP and GRIP projects could confidently get ice cores from Greenland that they felt represented a true climate record and by then they also had the proxies with the resolution to see the rapid changes that had taken place in the past. Given the nature of data collection, interpretation, peer-review and publishing, it wasn’t until 1993 that these results were published.
It took nearly another decade for this new, alarming, paradigm about how rapidly global climate can change to percolate through the scientific community, and, even today, much of the public is unaware that climate can change on a dime.
As for the ice sheets, when I was on the West Antarctic Ice Sheet in 1996, there was talk about the acceleratio of ice streams feeding the Thwaites and Pine Island glaciers, but the notion that there might be a significant increase in runoff from the ice sheet over the next hundred years was still very much a fringe idea.
With permafrost, the problem was a sparsity of data in the 80s and early 90s and it is understandable that scientists didn’t want to venture beyond the data.
The problem for society as a whole was that the muted consensus on the scale of the threat diminished any sense of urgency about dealing with the problem. Perhaps the best example of this was the early work of William Nordhaus. Working from the IPCC best estimates in the early 1990s Nordhaus published one paper in which he predicted the hit to the US GDP from climate change in 2100 would be about ½ of 1%. Nobody is going to jump out of their chair and demand action if the hit to the economy was going to be 0.5% of GPD a hundred years laterLibertarians such as William Niskanen seized on this and testified before Congress that there was plenty of time to deal with global warming if it was a threat at all.
And then there was the disinformation campaign of industry, particularly fossil fuel lobbyists, as well as pressure from unions (the UAW in particular) and the financial community. These highly motivated, deep-pocketed interests seized on scientific caution to suggest deep divisions among scientists and that the threat was overplayed. Little wonder then that the public failed to appreciate that this was a looming crisis that demanded immediate, concerted action.