How robust is it?
Not very. Certainly nowhere near enough to base policy on it.
I was very impressed by Bakker’s intellectual integrity and courage in tackling this topic in the 11th hour of completing his Ph.D. thesis. I am further impressed by his thesis advisors and committee members for allowing/supporting this. Bakker notes many critical comments from his committee members. I checked the list of committee members, one name jumped out at me – Arthur Petersen – who is a philosopher of science that has written about climate models. I suspect that the criticisms were more focused on strengthening the arguments, rather than ‘alarm’ over an essay that criticizes climate models. Kudos to the KNMI.
I seriously doubt that such a thesis would be possible in an atmospheric/oceanic/climate science department in the U.S. – whether the student would dare to tackle this, whether a faculty member would agree to supervise this, and whether a committee would ‘pass’ the thesis.
[Update a few minutes later]
In short, climate change is not worse than we thought. Some indicators are worse, but some are better. That doesn’t mean global warming is not a reality or not a problem. It definitely is. But the narrative that the world’s climate is changing from bad to worse is unhelpful alarmism, which prevents us from focusing on smart solutions.
A well-meaning environmentalist might argue that, because climate change is a reality, why not ramp up the rhetoric and focus on the bad news to make sure the public understands its importance. But isn’t that what has been done for the past 20 years? The public has been bombarded with dramatic headlines and apocalyptic photos of climate change and its consequences. Yet despite endless successions of climate summits, carbon emissions continue to rise, especially in rapidly developing countries like India, China and many African nations.
Because all of the hysteria, name calling and outright lies have appropriately destroyed their credibility.