The climate knowledge infrastructure was built to generate understanding of the global climate system. Its deep history, as well as its more recent role in climate politics, coupled it to national governments in both scientiﬁc and political terms. This infrastructure is currently challenged to “downscale” climate knowledge to meet the demands of city, county, and state agencies, as well as a wide variety of non-governmental organizations. Downscaling means much more than producing higher-resolution climate
data. It requires building technical, social, and institutional gateways that permit the transfer of knowledge – forecasts, causal theories, data, and interpretive or translational information – both to and from other knowledge infrastructures. This chapter argues that although the focus on a planetary scale matched the character of the problem as initially conceived, the same features that made it eﬀective at the planetary scale are now inhibiting use of climate knowledge for local, state, and regional planning. Processes now in play are likely to resolve these infrastructural mismatches, at least in part, but the legacy of knowledge built to serve global and national needs will remain a stumbling block for years to come.