Bill McGuire, who is Professor Emeritus of Geophysical & Climate Hazards at UCL, has written a post suggesting that climate scientists should speak out more and that they should
Come down off the fence and choose the path you know, in your heart of hearts, is the right one.
I must admit that when I started publicly discussing climate change – more than 8 years ago – I was a little surprised that more climate scientists weren’t speaking out. However, I think there are a number of reasons why this might be, many of which are quite reasonable.
I think scientists are naturally cautious about what they say publicly. The tendency is to say things for which there is substantial evidence and to avoid speculating about things that are very uncertain. There is also a tendency to avoid saying things that might sound like advocacy, especially when engaging in what might be regarded as reasonably formal science communication.
I do, though, agree with Bill McGuire that there is pressure to not sound alarmist. A consequence of this has been a tendency to focus on what is regarded as likely and to avoid talking about possible worst case scenarios. Again, this can be reasonable, but does run the risk of not making clear that things could end up much worse than what we regard as likely.
However, there is an additional complication. In a simple sense, the outcome depends on two somewhat independent factors: how much we end up emitting, and how sensitive the climate is to the resulting radiative perturbation. So, when considering worst case scenarios, are they worst case in the sense that the climate turns out to be very sensitive, or is it that we continue to increase our emissions, so that a worst case emerges even if climate sensitivity is not on the high end. Of course, the ultimate worst case would be that we continue to increase our emissions and climate sensitivity turns out to be high.
This does make science communication quite tricky, since we can still do things to limit how much we emit and, consequently, to avoid ultimate worst case scenarios. Consequently, there’s a balance between highlighting how bad things could get while also making clear that it’s still not too late to avoid some of the most severe outcomes. However, we also have the complication that even if we do limit our emissions, we could still experience impacts that are more severe than expected (e.g., the recent heatwaves and flooding).
So, I do think this is a pretty complex science communication environment and, in general, I think climate scientists have communicated very effectively (global governments have agreed to take action, even if they haven’t actually done much yet). I do think it would be good if more climate scientists were to speak out. However, I also think we have to be careful of generating a narrative that suggests that the problem is that climate scientists haven’t spoken out enough, rather than it being that others have mostly ignored what is being said.