One of the themes on this blog has been to try and get the message across that global warming is fundamentally about energy, not simply about global surface temperatures. Even though surface temperatures appear to have been flat for the last 10 years or so, the energy going into the oceans has continued to rise and provides very strong evidence that global warming continues unabated.
However, a typical response to the argument above is “when global surface temperatures were rising, scientists were happy to use it as evidence. Now that it’s stopped, they find something new”, or something along those lines. The basic argument seems to be that scientists used rising global surface temperatures as evidence of global warming in the past, and so now that they’ve been flat for a period of time that means that it should be seen as evidence that global warming has stopped. Changing the evidence is – in some sense – unscientific and just suggests that scientists are clutching at straws and/or being dishonest/unscientific.
The first issue I have with this is that I don’t think it is strictly true. The basics of global warming has been well understood for decades. It’s always been about excess energy entering the climate system. Rising surface temperatures is a manifestation of global warming, but not necessarily a good indicator on short timescales. I doubt that those claiming that scientists have changed their story have actually read any of the scientific literature. If they’re basing it on anything it’s on what they’re heard, seen, or read on the TV, the radio or in newspapers and magazines. As such, I’ve often wondered if this isn’t an example of the difficulties that scientists can face when engaging with the public.
Now I haven’t done a lot of public engagement but have – now and again – been on TV, the radio and been quoted in newspapers. I’ve had no media training and, typically, you get no warning. You’ll get a sudden call to ask if you can go on TV later that day or a reporter simply phones to ask a few questions. So, not only do you not get much time to prepare you also have to quickly work out how to explain your science to a general audience. You need to make it accessible without being completely wrong. Not only do you not really have time to go into details, you also know that doing so in the general media is not really going to be particularly effective. I’m not trying to be insulting to the general public, but if you’re trying to get some basic science across in an interview or a newspaper article, going into the details is not really going to help much.
Now when I’ve engaged with the media, I’ve always known that how I explain something might be seen – by an expert – as simplistic and maybe even, strictly speaking, “wrong”. However, most who’ve done public engagement recognise that it’s a balancing act. You’re trying to get a scientific message across to the general public in a way that is accessible. If climate scientists did indeed use global temperatures as indicators of global warming in the past, this may simply have been a consequence of trying to find an accessible way to explain global warming to the general public. It’s something people understand and can identify with (temperatures are likely to go up). Explaining that CO2 can absorb and scatter outgoing long-wavelength radiation, causing more and more energy to remain in the climate system, leading to a rise in surface temperatures so as to re-establish equilibrium, is probably too complex for a few minutes on a radio programme.
Most scientists don’t really have to worry that what they’ve said in some newspaper article or radio programme will come back to haunt them in later years. I suspect that climate scientists didn’t really worry about it themselves either. They were simply engaging with the public as they were probably encouraged to do. You could argue that they should have realised and been more careful about what they said and that they should have had proper media training. One immediate problem is that Universities don’t really care. They’re just keen for their researchers to be in the media. The other issue is that, in my opinion, it really wouldn’t have made any difference. It’s normal for scientific evidence to change with time, so even if researchers had been incredibly careful about what they said, those who don’t want to believe or who want to mis-inform would have found something to criticise anyway.