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The rapid increase in computing demand and corresponding energy consumption have focused attention on computing's impact on the climate and sustainability. Prior work proposes metrics that quantify computing's carbon footprint across several lifecycle phases, including its supply chain, operation, and end-of-life. Industry uses these metrics to optimize the carbon footprint of manufacturing hardware and running computing applications. Unfortunately, prior work on optimizing datacenters' carbon footprint often succumbs to the sunk cost fallacy by considering embodied carbon emissions (a sunk cost) when making operational decisions (i.e., job scheduling and placement), which leads to operational decisions that do not always reduce the total carbon footprint. In this paper, we evaluate carbon-aware job scheduling and placement on a given set of servers for several carbon accounting metrics. Our analysis reveals state-of-the-art carbon accounting metrics that include embodied carbon emissions when making operational decisions can increase the total carbon footprint of executing a set of jobs. We study the factors that affect the added carbon cost of such suboptimal decision-making. We then use a real-world case study from a datacenter to demonstrate how the sunk carbon fallacy manifests itself in practice. Finally, we discuss the implications of our findings in better guiding effective carbon-aware scheduling in on-premise and cloud datacenters.
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On the Promise and Pitfalls of Optimizing Embodied Carbon
To halt further climate change, computing, along with the rest of society, must reduce, and eventually eliminate, its carbon emis- sions. Recently, many researchers have focused on estimating and optimizing computing’s embodied carbon, i.e., from manufactur- ing computing infrastructure, in addition to its 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 op- erational carbon, which represents upstream companies’ embodied carbon. Yet, as we discuss, focusing attention on embodied car- bon 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.
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- PAR ID:
- 10433371
- Date Published:
- Journal Name:
- ACM Workshop of Hot Topics in Sustainable Computing
- Page Range / eLocation ID:
- 1-6
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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