This is a re-post from And Then There’s Physics
It seems that the US Department of Energy has now disbanded the Climate Working Group that drafted the report that I discussed in this post. However, about a week ago, Steven Koonin – one of the authors of the report – had an article in the Wall Street Journal titled At Long Last, Clarity on Climate. Clarity is a bit of a stretch. Personally, I think it more muddied the waters, than brought clarity.
A general point that I didn’t really make in my previous post (and that has just been highlighted in a comment) is that it is explicitly focussed on the US. The richest country in the world probably is more resilient than most others and could well decide that it’s better to deal with the impacts of climate change than committing too much now to avoiding them. I happen to disagree with this as I think it ignores how the US has benefitted from something that will negatively impact others, ignores that countries can’t really exist in isolation, and ignores that there are potentially outcomes that even wealthy a country will struggle to deal with. However, I can see how some might conclude this, although it might be good if they were much more explicit.
What I thought I would do is try to address some of the claims and conclusions made in Steven Koonin’s article. There’s an element of truthiness to the article; some claims may be true, but they don’t really support the argument being made.
For example, he says:
While global sea levels have risen about 8 inches since 1900, aggregate U.S. tide-gauge data don’t show the long-term acceleration expected from a warming globe.
U.S. tide-gauges may indeed not show the expected long-term acceleration, but the rate of global sea level rise is indeed accelerating.
Similarly, he says that:
Data aggregated over the continental U.S. show no significant long-term trends in most extreme weather events. Claims of more frequent or intense hurricanes, tornadoes, floods and dryness in America aren’t supported by historical records.
Some of the statements (no long-term trends, historical records) may indeed be technically true. However, there are numerous studies that have shown that climate change has affected extreme events in Northern America. You can find many examples in this Carbon Brief article that has mapped how climate change affects extreme weather around the world.
He also claims that:
Natural climate variability, data limitations and model deficiencies complicate efforts to attribute specific climate changes or extreme events to human CO2 emissions.
I suspect these factors do indeed complicate efforts, but so what? It is complicated, but that doesn’t mean that studies haven’t been done that do indeed demonstrate that human CO2 emissions are driving climate change and influencing extreme events.
I’ll end this bit with a comment about something he says about climate models:
Complex climate models provide limited guidance on the climate’s response to rising carbon-dioxide levels. Overly sensitive models, often using extreme scenarios, have exaggerated future warming projections and consequences.
There is a hot model problem, but there are ways to correct for this, and climate models have generally been skillfull. Also, climate models are typically making projections – or conditional predictions – because the emission pathways are inputs to the models. Hence the result is telling us something about what might happen if we follow that emission pathway. The emission pathways that are considered range from ones where we soon start reducing emissions to ones where it continues increasing. To suggest that climate models have exaggerated future warming projections when the emission pathways are inputs seems a little confused.
I’m not writing this to try and change the minds of those who think the DOE climate report was excellent and who think that the authors are some of the best scientists in the field. That would be silly and naive. I’m partly writing this because it’s a rainy Saturday afternoon and it’s a topic I find interesting.
However, another reason is that I think it’s important to think about why people with relevant expertise can write something that seems intellectually weak and sloppy, but present it as if it’s a careful piece of work that’s provided clarity. Would be easy to conclude that it’s simply them being dishonest, but I’m not convinced it’s quite that simple or convenient.
I wouldn’t be surprised if the authors believe that they have written a good report and that what they’ve presented has provided some clarity. So, how do you have serious discussions about complex topics when people who are regarded as experts in the field can’t even decide on some of the scientific fundamentals, or the significant of what the scientific evidence suggests? I certainly don’t know the answer, but I do think it is something worth thinking about.
Links:At Long Last: Clarity on Climate – Steven Koonins WSJ article.The New DOE Climate Report – my earlier post on the DOE Climate Report, with a link to the report.Trump’s Energy Department disbands group that sowed doubt about climate change – NPR article about the DOE CWG being disbanced.Climate Change: Global Sea Level – NOAA webpage highlighting that the rate of global sea level rise is accelerating.Mapped: How climate change affects extreme weather around the world – Carbon Brief article mapping attribution studies for extreme events.The ‘hot model’ problem – my post about the hot model problem.Evaluating the Performance of Past Climate Model Projections – paper by Hausfather et al.Past warming trend constrains future warming in CMIP6 models – Tokarska et al. with a method for downweighting models based on how well the agree with past warming trends.
