Our final guest lecture for Climate Change in History came from Paul Edwards of Stanford University, a leading expert in the history of climate science who has served on the IPCC. Edwards blends science and technology studies (“STS”) with history of science and history of technology to look at climate science from the point of view of the infrastructures and institutions that support it, or what he calls “knowledge infrastructures,” as developed in depth in his landmark study A Vast Machine. For this talk, Edwards focused on temporal scaling, the telescoping time-scales of “technological momentum” and the “temporal commitments” behind infrastructure, which shape our dependence on infrastructures and the long-term risks that come with it. This scalar perspective, which he shares with one of our previous guest speakers, historian Deborah Coen (see here and here), helps explain the temporal challenges and risks of the Anthropocene, in which decade- or century-scale decisions can have consequences on millennial or epochal scales.