There's an interesting post at Real Climate about a session on climate change at the International Geological Congress. Apparently, the session included quite a few speakers who are skeptical about human-caused climate change, which led Rasmus Benestad (the Real Climate contributer who wrote the article) to ask:
What is going on? Is there a higher proportion of geologists that have a completely different view on climate change, or was this a biased representation of the community?
To be honest, I don't know. I do know geologists who are skeptical about human-caused climate change. Most of them are retired petroleum geologists. (That may be due to sampling bias, however; Durango is one of those places where geologists go to retire, and the Four Corners Geological Society is affiliated with AAPG, so I drink with retired petroleum geologists about once a month.) But last fall, I also saw a talk by a petroleum geologist who tried to explain why he was convinced that humans are affecting climate, and saw a number of industry geologists thinking about what he said.
Here's an edited version of what I said in a comment on Real Climate. I'm curious what other people think. Why are many geologists resistant to the idea of human-caused climate change?
I’m a solid-earth geologist (structural geology, metamorphic petrology), and I agree with Steve Milesworthy. [Milesworthy observed that the arguments of skeptical geologists tend to be, essentially: 1) there have been natural warm spells in the past, so the current climate change is also natural; 2) life has survived climate change in the past; and 3) climate science is just modeling and can't be trusted.] But I think there's more too it than that.
The fundamental assumption of geology is uniformitarianism: the present is the key to the past. We’ve recently been trying to convince the world that we’re relevant to humans because the past can also say something about the future: earthquake hazards, volcanic hazards, flood hazards - geology can give a longer-term perspective than history, and tell us that, for instance, a 5000-year-old volcano is potentially dangerous.
Geologists can get misled by uniformitarianism, though. The past helps us understand the future, but only if the same physical and chemical processes are operating. It’s hard for geologists to accept that humans are more than temporary, surface-scratching creatures - that we can affect the underlying physical and chemical processes that drive the geology that we study. And it’s hard to trust ideas that come out of physical and chemical models when they aren’t confirmed by something that we see in rocks. (Geologists will often dredge up the example of Lord Kelvin’s attempt to determine the age of the Earth from heat flow calculations - Kelvin was very wrong, because his model was incomplete, not because models are inherently useless.) And geologists have known for a long time that climate changes, so if it was natural in the past, there’s no reason to blame humans…
…except that there are good reasons to blame humans, and climate scientists have built a convincing case based on many different lines of evidence. (Geologists should respect that; it’s essentially the same way that solid earth geoscientists build big ideas.) You can’t test whether humans cause climate change by looking at a time when humans weren’t around… it’s like proving that magma doesn’t cause metamorphism by looking at metamorphic rocks that were heated by other processes. Geologists should get that, because we think that way, too.
And most geologists who have been in grad school since the late 80’s do accept and respect climate research. If we’re in the same departments, or have climate researchers coming to department seminars, then we hear and understand the arguments. But people who work in government agencies that separate geology from climate, or who work in oil & gas or mining, or who work in academic departments that are strictly solid earth - well, those people aren’t directly exposed to the current thinking of climate researchers. And they are perfectly capable of thinking about climate like geologists did in the 70’s. (Milankovitch, Milankovitch, Milankovitch.)
So geologists should accept climate change, but there are lots reasons why some don’t. The reasons are bad, but they exist.