I’m sure many would disagree, but although I’m clearly aligned with those who are regarded as alarmists, I’ve tried quite hard to avoid alarmist rhetoric. That doesn’t mean I’m not concerned/alarmed, just that my intent here was to discuss (mostly) the scientific evidence and to address what others have said that I think is not backed up by the scientific evidence. I also thought, naively probably, that if I avoided alarmist rhetoric, it might be possible to actually have interesting exchanges with those who disagree with the current scientific views. It’s worked in some cases, but not all that often.
Yesterday, however, I watched an interview between Thom Hartmann and Michael Mann in which Michael Mann discusses the possibility that we could reach one or more tipping points. A tipping point is simply some sudden climatic shift that happens quickly (on geological timescales at least) and can’t be stopped once it starts. Examples would be the continued decline of ice sheets (Greenland, West Antarctic) or the relatively sudden release of greenhouse gases trapped in the Arctic. None of these would be as catastrophic as a Venus-like runaway (which is virtually impossible) but still could have significant negative impacts and possibly could lead to some kind of mass extinction event (removing a large fraction of the species on the planet).
So, although I’ve tried to not use alarming rhetoric, it’s hard not to be alarmed when listening to Michael Mann describing these tipping points. What was particularly poignant was the point he made about this being the only planet we have. There is absolutely no chance that we can move to another habitable planet in the foreseeable future. We don’t know where any others are at the moment and we don’t have the technology to get there even if we did. It seems remarkably foolish, given the scientific evidence, to be risking our existence on this planet simply because some can’t quite bring themselves to accept that we might be changing our climate in ways that could be extremely damaging. Maybe it’s not absolutely certain that we are (well, actually, it pretty much is) but even so, why take the risk? Anyway, I recommend watching the video. It might be alarming, but it’s worth watching.