  To halt further climate change, computing, along with the rest of society,
must reduce, and eventually eliminate, its carbon emissions. Recently, many
researchers have focused on estimating and optimizing computing's
\emph{embodied carbon}, i.e., from manufacturing computing infrastructure, in
addition to its \emph{operational carbon}, i.e., from executing computations,
primarily because the former is much larger than the latter but has received
less research attention. Focusing attention on embodied carbon is important
because it can incentivize i) operators to increase their infrastructure's
efficiency and lifetime and ii) downstream suppliers to reduce their own
operational carbon, which represents upstream companies' embodied carbon. Yet,
as we discuss, focusing attention on embodied carbon may also introduce harmful
incentives, e.g., by significantly overstating real carbon reductions and
complicating the incentives for directly optimizing operational carbon. This
position paper's purpose is to mitigate such harmful incentives by highlighting
both the promise and potential pitfalls of optimizing embodied carbon.
