The Global Warming Policy Foundation (GWPF), who I’ve written about many times before, have released a report which they’ve described as [t]he World’s first state of the climate survey based on observations only. I think it’s meant to the a response to the WMO’s State of the Global Climate Report, which I would recommend reading, rather than reading the report produced by the GWPF.
The GWPF’s report is full of the standard talking points, so I won’t bother rebutting them again. I was going, instead, to make a more general point about their suggestion that it is based on observations only. It’s clearly intended to suggest that their report is somehow pure and uncontaminated by nasty things like models. However, this doesn’t make any real sense. You can’t really do any kind of research without some kind of model.
Even making observations requires models; you need some way to convert whatever happens in the measuring device into a quantity that represents some property of the system that is being observed. It could be as simple as converting a change in height of Mercury in a thermometer into a temperature, or as complex as trying to determine the temperature in the troposphere from satellite radiance measurements. Either way, you still need some kind of model in order to make meaningful observations of the system being studied.
However, even if we accept that we can make observations that are not significantly influenced by the underlying models, observations – by themselves – tell us very little. They might be able to tell us if some property of a system is changing, but without some kind of model, we won’t know why it is changing, or what such changes might tell us about the system being observed. Models are a key part of doing research and suggesting that their report is based on observations only is not only wrong, but also indicates that they don’t even have a basic understanding of how research is undertaken (okay, there is an alternative interpretation, but I’m trying to be polite).