I was a little ticked-off that someone, who made what appeared to be a reasonably pleasant comment on my blog, later referred to me, on their blog, as a “warmist”. It’s not that there is anything fundamentally rude about the word “warmist”, it’s that it’s clearly intended to be derogatory. There are similar terms, like “warmunist” and “warmmonger” that fall into the same category. I have tried to avoid using terms like “denier” because I don’t really like categorising people in this way. It seems lazy. If you think someone is mistaken, then put some effort into explaining why you think they’re wrong. That’s why I’m writing this blog. If you disagree with something, you’re welcome to tell me and to try and convince me that I’ve made a mistake. In fact, I’m sure I have made some mistakes.
Having thought about this a little more though, I wondered if one shouldn’t start taking pride in the term “warmist”. There’s nothing fundamentally wrong with the word and there’s extensive evidence suggesting that the world is indeed warming. For example, the figure below is from Loeb et al. (2012) (Observed changes in top-of-the-atmosphere radiation and upper-ocean heating consistent within uncertainty). The black line in both figures shows the CERES measurements of the Top Of the Atmosphere (TOA) flux and indicates that since 2001 the Earth has been receiving an excess of between 0.5 and 1 W m-2. This, by definition, is warming. If you don’t believe this is happening (i.e., you’re not a “warmist”) you need to explain what’s wrong with this measurements. If you believe the measurements are correct, then presumably you’re a “warmist”.
Of course, at this stage we simply know (from the CERES measurements) that the Earth is warming. We don’t know, from these measurements, what’s causing this warming. It’s thought that the flux from the Sun has increased by 0.25 W m-2 since the late 1700s, so this could explain some, but not all of this warming. What’s more, however, is that the surface temperature of the Earth has increased by about 1oC since the mid-1800s. An increase of 1oC leads to an increase in flux from the surface of 5.5 W m-2. So, we’re getting 0.25 W m-2 more from the Sun at the top of the atmosphere, we’re radiating 5.5 W m-2 more from the surface of the Earth and yet there is still a 0.5 to 1 W m-2 excess at the top of the atmosphere.
Either, the TOA excess in the mid-1800s was massive and we just haven’t yet reached equilibrium yet, or something is preventing a large fraction of the excess energy (compared to that emitted in the mid-1800s) from getting to the top of the atmosphere. What else has changed since the mid-1800s. Well, we’ve increased CO2 concentrations in the atmosphere by 40%. Calculations suggests that this – together with increases in other greenhouse gases – could contribute 2.4 W m-2. That could be it then. Maybe the measured warming is anthropogenic. I certainly think there is plenty of evidence to suggest that it is. Maybe others disagree, but I don’t think anyone else has a alternative forcing that is consistent with observations though.
Anyway, the point of this post was to suggest that being a “warmist” should be regarded as positive. It means you’ve accepted the reality that the Earth is currently undergoing global warming. If you disagree, you need to explain what’s wrong with the measurements. You can’t simply wave your hands and claim that it doesn’t make sense. As far as the consequences of this warming is concerned, well that’s more complex. I’m not sure we can say for certain. I would argue, however, that continually adding energy to our climate system will presumably change our climate. Will it be good or bad? I guess we can’t say for sure, but more extreme weather events seems a likely outcome. What about increased CO2 levels. Some plants might like this, but there is actual evidence to suggest that this isn’t universally true. Furthermore, there appears to be increasing evidence that enhanced levels of CO2 is leading to acidification of our oceans. I’d be quite keen to see someone explain why they think this will be good for the fish.