The following list is intended to help you recognise and understand some of the misinformation about the carbon footprint of digital preservation that you may encounter.
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1. Myth: ‘Operational energy is all that matters.’ Only the electricity used during operation (e.g., running servers, desktops, or cooling systems) contributes significantly to carbon footprint. |
Reality: Embodied carbon – the emissions from manufacturing, transporting, and disposing of hardware – can be substantial, especially in short hardware refresh cycles. For some devices, embodied emissions can exceed operational emissions over their lifetime.
Chen, X., Han, L., Bhagavathula, A., and Gupta, U. (2025) CarbonClarity: Understanding and Addressing Uncertainty in Embodied Carbon for Sustainable Computing. Cornell Tech. [CarbonClarity: Understanding and Addressing Uncertainty in Embodied Carbon for Sustainable Computing]
This study explicitly states that ‘operational use is no longer the dominant source of emissions’ and demonstrates through case studies that embodied carbon is a significant – and often larger – component of total emissions for modern ICT systems.
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2. Myth: ‘Cooling is a minor factor.’ The energy used for cooling IT equipment is negligible. |
Reality: In data centres, cooling can account for 30–50% of total energy use. Efficient cooling design (for example, hot aisle/cold aisle containment, liquid cooling) can significantly reduce carbon impact.
Congressional Research Service (2025) Data Centers and Their Energy Consumption: Frequently Asked Questions [Data Centers and Their Energy Consumption: Frequently Asked Questions | Congress.gov | Library of Congress]
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3. Myth: ‘Carbon calculators are always accurate.’ Online carbon footprint calculators provide precise and reliable figures. |
Reality: Many calculators use generic assumptions (for example, average energy mix, standard usage patterns) that may not reflect local conditions or specific hardware configurations. This can lead to under- or over-estimation. It is difficult to track real-world carbon usage in detail (for example down to the energy used per CPU operation) and there is a trade-off between the accuracy of the information, and the time and energy required to generate it.
Xia, Z., Liu, K., Li, J. et al. (2025) Evaluating carbon footprint calculators: a comprehensive assessment framework. Clean Technologies and Environmental Policy 27, pp. 3947–3958. https://doi.org/10.1007/s10098-025-03169-x
This study compared 24 publicly available Carbon Footprint Calculators (CFCs). The authors of this study stated that ‘…we observed discrepancies in carbon footprint estimates among the CFCs (standard deviation equals 2.3 tons CO2 Emissions per capita), which means that the calculation design of the carbon footprint calculators is inconsistent.’
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4. Myth: ‘Green energy means zero carbon.’ Using renewable energy eliminates the carbon footprint of computing. |
Reality: While renewables reduce operational emissions, they don’t eliminate embodied emissions. Also, the carbon intensity of renewables varies by source and region (for example, biomass vs wind). It’s also worth noting that some ‘green’ options are in effect time-shifting the carbon impact (for example, releasing previously captured carbon).
Liu, H. and Zhai, J. (2025) Carbon Emission Modeling for High-Performance Computing-Based AI in New Power Systems with Large-Scale Renewable Energy Integration. Processes 13, no. 2, p. 595. https://doi.org/10.3390/pr13020595
The authors note that operational emissions (which account for approximately 87% of total life cycle emissions in the environment they were modelling) can be significantly reduced by using renewable energy. However, embodied emissions are not directly affected by use of green energy and ‘remain constant’.
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5. Myth: ‘Idle devices don’t consume much power.’ If a computer or server or monitor is idle or in sleep mode, it’s not contributing to emissions. |
Reality: Many devices still draw significant standby power, especially if not properly configured for energy efficiency. Networked devices like printers or routers often stay on 24/7.
Lawrence Berkeley National Laboratory (2024) United States Data Center Energy Usage Report. 2024 United States Data Center Energy Usage Report | LBL ETA Publications
This report highlights that a significant portion of data centre energy use comes from IT equipment that remains powered even when underutilized or idle, contributing to overall standby loads. Although it has fallen from percentages observed in earlier years, it is now ‘...relatively constant, if not increasing, with idle power fractions at 20–25% [of the maximum rated power of the server] in recent years.’
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6. Myth: ‘Upgrading hardware is always greener.’ Replacing old hardware with newer, more energy-efficient models reduces carbon footprint. |
Reality: The embodied emissions of new devices can outweigh the operational savings unless the old hardware is truly inefficient or failing. Extending the life of existing equipment is often more sustainable.
Tomlinson et al., (2023) Something Old, Something New: Extending the Life of CPUs in Datacenters. ACM SIGEnergy Energy Informatics Review https://hotcarbon.org/assets/2022/pdf/hotcarbon22-tomlinson.pdf
Longer lifespans amortize manufacturing emissions. ‘The most direct way to reduce the environmental impact of datacenters is to amortize the manufacturing emissions of hardware over longer timespans by keeping hardware in production beyond today’s relatively short refresh cycles.’
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7. Myth: ‘Cloud computing is always greener.’ Moving to the cloud automatically reduces your carbon footprint. |
Reality: While hyperscale cloud providers often use efficient infrastructure and renewable energy, the actual impact depends on usage patterns, data transfer volumes, and provider transparency. Not all clouds are created equal. ‘Cloud’ is a euphemism for ‘computer somewhere else’ so cloud use can also lead to carbon impact shifting to alternative locations.
Sukumaran Nair, S. (2024) Challenges and concerns related to the environmental impact of cloud computing and the carbon footprint of data transmission. Journal of Computer Science and Technology Studies, 6(1), pp. 21–30. https://doi.org/10.32996/jcsts.2024.6.1.21
The ‘greenness’ of cloud computing is not a given and depends on provider, workload, and transparency, to say nothing of the additional e-waste factors. ‘...the environmental impact of cloud computing, e-waste generation, and the carbon footprint of data transmission are significant challenges and concerns that need to be addressed.’
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8. Myth: ‘Hardware and software choices are the only things that matter.’ Hardware and software choices (and their embodied carbon and operational costs) are the only things that matter when it comes to calculating or reducing carbon costs. |
Reality: Collecting and retention policies directly influence the volume, duration, and redundancy of stored data, which in turn affects carbon emissions:
Long Retention = Higher Emissions
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More storage = more hardware, energy, and cooling.
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Frequent migrations to newer media increase embodied carbon.
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Verification processes (e.g., fixity checks) consume compute cycles.
Selective Retention = Lower Emissions
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Appraisal and deaccessioning reduce unnecessary storage.
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Tiered storage (e.g., cold vs hot) optimizes energy use.
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Retention schedules aligned with value and access frequency minimize waste.
Jia, Y., Deng, M., Burger, R., Sheard, S., Hanneman, K., Drucker Iarovich, M., Sala, E., Avesani, G., Illing, R.O., and Rockall, A.G. (2025) Greenhouse gas emissions due to long-term data storage of CT with reformats and strategies for mitigation. European Radiology, 35(2), pp. 381–395. https://doi.org/10.1007/s00330-025-12023-z
Retention policies strongly influence carbon impact. In the study above, a combined modified retention policy and storage strategy achieved an emission reduction of 89% compared with the unmodified emissions.
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9. Myth: ‘Carbon is the only thing that affects environmental impact.’ Carbon has the most damaging environmental impact so concentrating on mitigating emissions will solve the environmental problem. |
Reality: There are other areas we should be aware of when considering the environmental impact of our digital preservation activities (see table below):
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Impact Type |
Description |
Exacerbated by |
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E-waste |
Disposal of obsolete storage media and servers |
Frequent media migrations, short hardware life cycles |
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Water usage |
Cooling systems in data centres |
High-density storage and compute cycle |
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Rare earth mining |
Used in hard disk drives (HDD), solid state drives (SSD), and networking gear as well as end user devices |
Large-scale hardware deployments |
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Toxic materials |
Batteries, solder, and plastics |
Poor recycling practices |
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Land use |
Data centre construction |
On-premise scaling without virtualization |
Pendergrass, K.L., Sampson, W., Walsh, T. and Alagna, L. (2019) Toward Environmentally Sustainable Digital Preservation. The American Archivist 82 (1), pp. 165–206 https://doi.org/10.17723/0360-9081-82.1.165
Carbon is NOT the only thing that affects environmental impact. Other impacts include e-waste, water, rare earth mining, toxic materials (ICT life cycle impacts include resource depletion and waste). ‘Digital preservation relies on an interconnected infrastructure known as information and communication technology (ICT). This infrastructure includes items such as personal and handheld computing devices, other items with embedded microprocessors or network connectivity, data centers, cellular towers, satellites, and the networking infrastructure required to connect them all… [which] have a negative environmental impact throughout their life cycles.’
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10. Myth: ‘Storage is low impact.’ Storage is low impact compared to compute. |
Reality: Storage impact has a similar order of magnitude impact to compute. For instance, storage accounts for 33% of operational and 61% of embodied emissions in Azure’s general-purpose cloud. It’s true that tape storage is far more sustainable than HDD/SSD, but migration and redundancy add complexity. In addition, digital preservation involves active processes (for example migrations and fixity checks), which consume compute and energy. Finally, ‘dark data’ and redundant storage increase emissions and e-waste.
McAllister, S., Kazhamiaka, F., Berger, D. S., Fonseca, R., Frost, K., Ogus, A., Sah, M., Bianchini, R., Amvrosiadis, G., Beckmann, N., and Ganger, G.R. (2024) A Call for Research on Storage Emissions. In Proceedings of the 3rd Workshop on Hot Topics in Sustainability of Systems and Software (HotCarbon ’24). ACM. https://hotcarbon.org/assets/2024/pdf/hotcarbon24-final126.pdf
‘Recent data from Azure suggests that storage-related emissions – including storage racks and local storage devices – make up 33% of operational and 61% of embodied emissions in general-purpose cloud environments. Storage racks alone account for 24% of operational and 45% of embodied emissions’. This makes storage a dominating contributor to data centre emissions even as compute becomes more efficient.
Addis, M. (2024) Measuring and Managing the Carbon Footprint of Digital Preservation. International Conference on Digital Preservation 2024 (iPRES 2024), Ghent and Flanders, Belgium. Zenodo. https://doi.org/10.5281/zenodo.13682874
‘Embodied footprint of ICT equipment (servers, storage, networking etc.) used in Long Term Digital Preservation is the ‘elephant in the room’ and typically gets ignored. Life Cycle assessment (LCA) should be used to estimate the contribution to carbon emissions when used on-premise or in the cloud.’
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11. Myth: ‘Preserving data forever is sustainable.’ Preserving data forever, once ingested, is a sustainable approach. |
Reality: Indefinite retention is environmentally costly; appraisal, regular reappraisal, and selection are critical to reduce the impact (both environmentally and financially).
Pendergrass, K.L, Sampson, W., Walsh, T. and Alagna, L. (2019) Toward Environmentally Sustainable Digital Preservation. The American Archivist 82 (1), pp.165–206 https://doi.org/10.17723/0360-9081-82.1.165
‘...organizations should evaluate the environmental and financial impact of this decision and create policies and procedures for deaccession and destruction.’
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12. Myth: ‘Digital preservation systems are passive.’ Digital preservation systems are passive so, once objects are ingested, there is no environmental impact. |
Reality: Digital preservation systems regularly run active processes like fixity checks, replication, and migrations. Policies which govern the frequency of these activities will affect the overall environmental impact of a digital preservation instance. This impact should be considered when drafting these policies.
Pendergrass, K.L., Sampson, W., Walsh, T. and Alagna, L. (2019) Toward Environmentally Sustainable Digital Preservation. The American Archivist 82 (1), pp.165–206 https://doi.org/10.17723/0360-9081-82.1.165
The authors state that digital preservation relies on information and communication technology (ICT) infrastructure, which has considerable negative environmental impacts throughout its life cycle, not just during active use. They emphasize that preservation activities involve continuous energy consumption for storage, processing tasks (e.g., fixity checks, migrations), and cooling systems, and these impacts are often overlooked in sustainability discussions.