Climate policy and climate science are necessarily joined closely together. But there are good and bad ways of making the connection, and the worst is to tweak the science to say what policy-makers want to hear. We chuckle at the way some condemn earlier societies for the supposed subordination of inquiry to religious dogma and political whim. But the insistence on a drastic policy response to human GHG emissions ought rightly to be driven by a sense of certainty that something bad is happening or is about to. And on that score, as Roger Pielke Jr. wrote recently, “The importance of baselines for expected change came to mind over the weekend when I came across this unvarnished misinformation from an oft-quoted climate scientist: ‘The damaging impacts of climate change, and in particular from more extreme weather events, such as wildfires, floods, heatwaves, more intense hurricanes, are actually in many respects exceeding the predictions made just a decade ago.’” If true it clearly mandates immediate action. Politicians for some reason want it to be true and certainly most of them believe it. But as Pielke Jr. adds, it’s not true. It is flatly contradicted by what we really know about recent weather trends, and by the degree of uncertainty involved.
The claim of course came from none other than Michael Mann whom the Guardian just happened to interview. Of all the scientist joints in all the universities in all the world, they walked into his. And got a two-decker nonsense sandwich. As Pielke Jr. says:
“Ten years is not nearly long enough to detect and attribute damaging impacts from changes in climate, or even to simply detect changes in climate”
And
“On any time scale, the IPCC has not detected or attributed changes in wildfires, floods, or hurricanes (it has for heatwaves, over many decades)”
Now in some sense those two point in opposite directions. If a decade is not nearly long enough, then even many decades is doubtful as a period for signal to emerge from noise with respect to inherently fluctuating phenomena including, we say, heatwaves. (Plus Tony Heller’s archival spelunking strongly suggests that heatwaves were far worse in the United States in the 1930s, and it’s about the only place where systematic record-keeping permits such a firm statement.) But in fact the IPCC has not positively said there’s no change, it says it hasn’t managed to detect anything meaningful either way. Sometimes you just can’t get a reliable answer to a question even if it’s very important to do so.
It is part of a point that gets lost far too often in the debate, especially as the gears mesh or clash over science driving policy. It’s not that the Michael Manns of this world say they know everything is far worse than they ever predicted so we should trust their current predictions, and skeptics such as CDN say no, nothing’s going on. We say we do not know what is happening.
We do not know if the Holocene is winding down into another glaciation, which is unfortunate since if so we face a genuinely existential climate crisis. We do not know if it is continuing to warm in the rebound from the Little Ice Age or leveling off. We do not know if the weather is getting better or worse because of what is or is not happening. And we therefore are trying to stand athwart alarmism yelling Stop.
"IPCC has not positively said there’s no change, it says it hasn’t managed to detect anything meaningful either way". The IPCC uses a convoluted form of words that leaves a lingering expectation that given, time and more data, a change will indeed emerge. This turns classical change detection on its head which conventionally starts with a null hypothesis of NO change. A statistical test based on this base case is used to either accept or reject that null hypothesis with a deliberately high bar set against rejection. But the IPCC was set up in a non-standard fashion with the remit to dig for evidence of change. The outcome is that it is the existence of change that provides the base case null hypothesis and it is its rejection (i.e. no change) that has the tough job . Thus we read in, for example, IPCC WG1 chapter 11 concerning extreme precipitation and hydrological events, "low confidence of observed changes" rather than "no evidence of observed changes" which would be the normal way of summarising failures to pass a significance test for trend.
There is no evidence that Climate Change is an existential, or any other kind of crisis. On the other hand, Climate Change Policy is a Clear and Present Danger to all Western style Liberal democracies. That is the language of National security - pretty clear who the antagonists are, and their desired end point - never been able to discern what their motivations are.
The main takeaway from the chat John had with Judith Curry for me at least,is that the Climate Alarmist Agenda house of cards is starting to crumble.You see it in things like the Carbon Tax here becoming an anathema for political parties here.And right-leaning parties winning more political power in EU elections.Wind turbine blades washing up on shore in New England.Stagnant sales of EV's everywhere.Just to name a few collapsing cards in the deck.BUT,it remains an uphill struggle.The alarmists and the political Left still possess a lot of power.Hopefully that will start to change Nov 5,and in Canada when Trudeau is finally removed from power,hopefully by next spring.