Jack O’Grady, Collections and Digital Access Specialist at Hamilton Public Library

Introduction

As the Collections and Digital Access Specialist, I was brought on to support the Hamilton Public Library (HPL) Local History & Archives (LHA) department with introducing a new digital preservation system for their extensive collection of digitized and born-digital records. Prior to 2024, LHA had maintained a growing collection of mostly digitized photographic material in the Canto Cumulus digital asset management system, as well as local network drive storage allotted by the HPL Digital Technology (DT) department. The loss of vendor support for Canto Cumulus and a cyberattack in 2024 led to the local network drive and Microsoft SharePoint becoming the main storage locations for LHA’s digitized material. The local network drive is backed up to offline tape storage at regular intervals, and the Microsoft SharePoint material is enmeshed in the wider Azure cloud ecosystem. This was the infrastructure set-up I began working with when starting this project, and it was understood to be temporary, put together in the wake of a cyberattack and intended to be replaced by the new digital preservation system I would be configuring alongside our chosen vendor, Preservica. Some material is also available through Flickr, the Internet Archive Canada, and other specialized databases.

Why we got involved in testing the DPC’s Carbon Footprint Toolkit

On a personal level, I had previous experience attempting to implement carbon footprint calculation practices while a student intern with the University of Toronto Libraries IT Services department. That project saw some success but was limited in scope and my own ability to commit time as a part-time student worker. With LHA, there was mutual interest among staff in deepening our understanding of the archive’s digital carbon footprint. Environmental sustainability is a stated commitment of the HPL system, ingrained in library policy, and was included in the LHA department’s Digital Preservation Strategy, which is working through the process of becoming library policy.

Working with the Carbon Footprint Toolkit was also a unique opportunity for LHA because of our position as a team implementing digital preservation for the first time. We understood how this positioned us to provide a helpful perspective for other institutions. The Toolkit would also encourage us to consider the technical infrastructure more carefully, which we believed would benefit the entire project and help the team make more sustainable decisions and be better stewards of all our resources (financial, computational, and environmental).

What we chose to focus on

The initial plan for testing the carbon footprint toolkit was to calculate LHA’s current footprint and compare it to the projected footprint for the new digital preservation system. We moved away from this focus as it proved more difficult than anticipated to secure data for the current system while in the middle of radically transforming it. As our infrastructure was in flux, the focus instead turned to how we could use this as an opportunity to build in interoperability with the carbon calculation footprint toolkit into our system. The goal became to think of, and proactively build tools, for capturing carbon footprint calculation data from the system, so that future teams would be able to use the carbon footprint spreadsheet tool more regularly and with more ease.

What we achieved

While initial efforts to map our current infrastructure were stalled by the system changing under our feet, as well as the people I needed to contact simply being too busy handling other projects, the pivot to the future system was much more effective. This work began by mapping the upstream and downstream activities which would impact the new digital preservation system’s carbon footprint, taking advantage of the already ongoing work to define those future workflows. From here, I identified points in those workflows where carbon footprint data which aligned with the toolkit could be extracted, before designing tools which would facilitate capturing it without over-burdening the team. What this has led to is a growing suite of data collection tools that, with some additional context, can feed data directly into the toolkit for easier calculation with the new system. These include:

• Modifications to the standard DPC Digital Asset Register template (https://www.dpconline.org/digipres/implement-digipres/dar-toolkit) to describe what machine data is stored on and log computational actions taken against it (i.e. checksums, etc.).
• Logs to record critical networking actions, specifically the digitization and uploading of new material, the movement of material from one storage location to another, and the creation of access copies/downloading of material for use by researchers.

The goal of these tools is to make collecting carbon footprint calculation data a part of the team’s workflows with the new system. Learning from the struggle to find data for the system being phased out, we were inspired to make this work easier for future teams. As a part of the manual for the new system, instructions for filling out, maintaining, and using these tools as a part of regular system governance are being drafted.

Lessons learned

This exercise showed for LHA how important creating open lines of communication and transparent systems are for this work. Without those in place, understanding the carbon footprint was too big of a task, there were too many moving parts and no birds-eye view. We were able to take advantage of being at the beginning of the process, so we moved to build in that birds-eye view and include carbon footprint governance into the system. Doing that work helped us have other helpful conversations because it required us to think critically about our infrastructure, so it’s useful for any team new to digital preservation.

Next steps

• Continue working with Preservica and internal IT team to acquire data centre information needed to contextualize carbon footprint data and make calculations.
• Work with internal web team to gain access to visitor and usage data for LHA’s web-based access points.
• Finish manual for the new digital preservation system, finalizing procedures for regularly capturing carbon footprint data in the archive’s day-to-day workflows.
• Include carbon footprint calculation in next annual benchmarking and digital preservation maturity review.

Kelli Bogan, George Washington’s Mount Vernon

Introduction

Owned and operated by the Mount Vernon Ladies Association (MVLA), George Washington’s Mount Vernon is a nonprofit historic site located in the United States and is dedicated to preserving, restoring, and managing George Washington’s estate as well as educating the public about its history and significance.

Mount Vernon’s digital archives program, established in 2024, is responsible for the stewardship of the organization’s digital materials, including the records of the MVLA and Mount Vernon. The program currently manages content across two on-premises digital servers and specialized cloud-based services.

Why we got involved in testing the DPC’s Carbon Footprint Toolkit

Our digital preservation program is still in its infancy and we are committed to developing and managing it in a responsible and sustainable manner. Understanding the impact of our practices and systems as they evolve will help us identify opportunities for improvement and make informed decisions about the future of the program.

We also wanted to represent the challenges and perspectives of medium-sized organizations and historic sites, which often have fewer resources for digital preservation than larger institutions. We have one staff member dedicated to digital preservation and a small IT team focused primarily on maintaining core systems and supporting operational continuity. While we are fortunate to have dedicated staff in both areas, our more limited resources make Mount Vernon a useful case for understanding how digital preservation approaches can be implemented with modest staff and infrastructure.

Lastly, like many smaller institutions, Mount Vernon is not currently a member of the Digital Preservation Coalition, but we regularly use its tools and resources to support our digital preservation work. Participating in this project allows us to contribute to a community whose expertise and resources we value, while advancing our commitment to digital preservation standards, solutions, and best practices.

What we chose to focus on

We chose to focus this study on our web archiving program, one of the first initiatives of the digital archives program. Its well-defined scope and growing body of content provide a useful dataset for examining the environmental impact of our practices.

Because automated web crawling through a cloud-based service is now our primary method of adding content to the web archive, we focused the study on this service and the systems and activities associated with it.

What we achieved

Our web archiving vendor provides a dashboard with information on crawls, uploads, storage, and usage history, giving us a starting point for understanding the scale and activity of our web archive. The service also provides a public-facing access portal, but we do not currently have information on how frequently users access it.

We contacted the vendor directly to request more detailed environmental data. They were receptive to our request and willing to investigate the information we needed. However, we learned that extracting data for an individual customer is a labor-intensive process for the vendor. At the time that this case study was written, we had not yet received the requested data.

Although we were not able to complete a full carbon calculation during the project period, using the toolkit helped us:

• identify the data needed for the assessment,
• understand the gaps in the information available to us, and
• clarify which data we can access directly and which depends on our vendor.

This provides a clear foundation for completing the calculation in the future.

Lessons learned

The project reinforced the importance of taking organizational capacity into account when assessing environmental impact. Our experience shifted our thinking from pursuing a single, highly precise carbon footprint number toward developing a repeatable approach to understanding and comparing the environmental impact of the systems and services we rely on.

For an institution of our size, regularly collecting highly detailed, customer-level data may require more staff time and effort than is practical, particularly when that data is also labor-intensive for vendors to produce. As the Toolkit itself notes, “Perfection is the enemy of the good here. Not all data are equal, and spending a lot of time and energy gathering really detailed data might contribute more to your carbon footprint than it would ever save.”

Next steps

Moving forward, we plan to focus on collecting environmental information at the vendor and service level and incorporating that information into future vendor evaluation and selection. This will allow us to compare systems, better understand vendors’ commitments to reducing environmental impact, and consider environmental factors alongside other procurement and service considerations. For example, our current vendor’s willingness to engage with our questions was itself a positive indicator and gave us greater confidence in continuing the relationship.

We also plan to investigate the energy associated with our complimentary manual web archiving activities so that we can better understand the environmental impact of activities that occur within our own institution, in addition to the services provided by vendors.

We don’t all need to be experts in climate science, but a little bit of knowledge can go a long way as you talk to colleagues, peers and work out how to tackle the challenge of calculating your carbon footprint. There are links scattered through this toolkit and this section isn’t intended to bring all of those together in one place, rather it provides a list of resources that you may want to follow up on to learn more about this topic. The list isn’t intended to be exhaustive but provides a helpful starting point if you would like to do further reading and research. Note that members of the Carbon Footprint Task Force also shared a range of different experiences and some of these are linked from how this toolkit was created.

General resources

• The DPC’s Technology Watch Guidance Note “Environmental Impact and Digital Preservation” by Eira Tansey provides a short and helpful introduction to this topic.

• The DPC’s webpage on the environmental impact of digital preservation includes links to blog posts and webinars from the DPC that are relevant to this topic. Our events on environmental sustainability have included a range of different speakers describing their own work in this area. DPC Members can see recordings from these events on the relevant event pages by logging in to the website.

  • Enacting Environmentally Sustainable Preservation – April 2020

  • Environmentally sustainable digital preservation - moving from theory to practice – November 2021

  • Digital Preservation and Environmental Impact – March 2024

• The NDSA Climate Watch Working Group curates and disseminates a list of resources on climate change that is of relevance to those working in the field of digital stewardship. You can subscribe to receive regular updates from this group which includes new and relevant articles on climate change.

• The 2026 revision to the NDSA Levels of Digital Preservation has introduced leaf icons to the Levels matrix to indicate those areas of the model where environmental considerations might come into play in decision making. A new Environmental Sustainability Guide has been developed to provide supporting information on these environmental considerations.

• An iPRES 2024 paper from Sibyl Schaefer includes really useful information about extraction of natural resources for the creation of computers and provides a framework for making decisions about the future: Energy, Digital Preservation, and the Climate: Proactively Planning for an Uncertain Future. 

• Toward Environmentally Sustainable Digital Preservation by Keith Pendergrass, Walker Sampson, Tessa Walsh and Laura Alagna from 2019 is a hugely informative paper which has been widely cited by those working in this area since.

• Sophia van Hoek’s 2023 report Walking a tightrope across the gap of digital preservation and environmental sustainability describes practical work carried out at the National Archives of the Netherlands to measure the carbon footprint of specific digital preservation activities and is well worth a read.

• Ross Spencer’s blog post for the Open Preservation Foundation, Monitoring carbon emissions of digipres activities at home describes an approach to answer the question “How much do I and my one computer, doing digital preservation tasks at home, impact the environment?”. It is an interesting read that also covers some of the complexity and uncertainty around this topic.

• 42 tips to make your heritage website more sustainable - this guide on greening the user interface is just one of the resources on green IT available via the Kenniscommunity Informatie en Archief

Resources about the DIMPACT methodology for carbon calculation

The DIMPACT methodology for carbon calculation inspired this DPC toolkit - if you would like to more about this, the methodology, a demo and a number of case studies can be found below:

• Methodology: Estimating the carbon impacts of serving digital media and entertainment products

• Demo: The DIMPACT Tool for Environmental Assessment of Digital Services

• Energy use and Greenhouse Gas Emissions in Digital News Media

• Using behavioural data to assess the environmental impact of electricity consumption of alternate television service distribution platforms

• Evaluating Sustainable Interaction Design of Digital Services: The Case of YouTube

The following case studies were developed from March to September 2026 by members of the Carbon Calculation Support Group. In March 2026 the DPC made a draft of the Carbon Footprint Toolkit available for community comment and testing. In order to fulfil a dual goal of gathering feedback about the toolkit and generating case studies, the DPC brought a small group together to meet monthly to work on using the Toolkit to carry out their own carbon calculations. Members of this new Carbon Calculation Support Group were not required to have any prior experience in this area, just an interest in the topic and enthusiasm to work on the challenge and share their knowledge and experiences.

Some of the members of the Carbon Calculation Support Group at our last meetings in September 2026.

Over a six-month period, group members met online every month and discussed how they were using the Toolkit. Participants shared challenges, successes and lessons learned, as well as providing valuable feedback on the Toolkit and helping to test and refine the Carbon Footprint Calculation Tool itself. Participants were able to learn from each other and discover shared challenges as well as providing support and advice to each other based on their own experiences. Alicia Wise of CLOCKSS chaired the sessions and provided valuable advice and encouragement along the way.

Carbon footprint calculation can be a complex and challenging area, typically involving a substantial amount of time and effort, as well as the input of colleagues and third-party service providers. It was recognised that it wasn’t realistic for group members to complete a full carbon footprint calculation for all of their digital preservation activities in this six-month period, but it was hoped that everyone would be able to make progress in a particular area and to be able to share those learnings back with the community. What follows is a series of case studies from group members covering a range of different areas and perspectives on their work over the last six months. These should not be viewed as complete and polished examples of carbon footprint calculations, rather as a set of examples of works in progress, describing what has been accomplished so far and where they see this work going next.

We would like to thank all the members of the Carbon Calculation Support Group for working with us on this task.

• Assessing the carbon footprint of cloud-services at a medium-sized institution - Kelli Bogan, George Washington’s Mount Vernon

• Building Interoperability with the Carbon Footprint Toolkit into the Hamilton Public Library’s Local History and Archives Department’s Digital Preservation System - Jack O’Grady, Collections and Digital Access Specialist at Hamilton Public Library

• Measuring the Carbon Footprint of Digital Preservation Activities using Permafrost: A Case Study with Wilfrid Laurier University and Scholars Portal - Amanda Oliver, Wilfrid Laurier University & Julie Shi, Scholars Portal

• Calculation of the carbon footprint of digital archiving activity at Ngā Taonga Sound & Vision in Aotearoa New Zealand - Kate Roberts (with input from Preservation and Property Operations colleagues at Ngā Taonga; Dan Eady, Luke Tearle and Steve Hutchinson), Ngā Taonga Sound & Vision

• Measuring the Carbon Footprint of a SaaS Preservation Repository at the University of Melbourne - Dr Eva Samaras and Elise Bradshaw, University of Melbourne

• What we learned from measuring the carbon footprint of comparative software infrastructure - Jemma Singleton, Newcastle University Library

• What we learned from measuring the carbon footprint of the CLOCKSS archive – Alicia Wise, CLOCKSS

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.

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.

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]

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.’

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’.

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.’

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.’

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.’

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

• More storage = more hardware, energy, and cooling.

• Frequent migrations to newer media increase embodied carbon.

• Verification processes (e.g., fixity checks) consume compute cycles.

Selective Retention = Lower Emissions

• Appraisal and deaccessioning reduce unnecessary storage.

• Tiered storage (e.g., cold vs hot) optimizes energy use.

• 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.

Reality: There are other areas we should be aware of when considering the environmental impact of our digital preservation activities (see table below):

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.’

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.’

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.’

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.

Preservation activities take place across both physical and digital domains, and these domains are deeply interconnected. Digitization of physical collections creates digital assets that require long-term management, storage, and access, often alongside the continued retention of the original physical materials. When a manuscript is digitized, for example, the original still needs to be preserved and stored in appropriate conditions, as well as its digital counterpart. As a result, many organizations now carry parallel preservation responsibilities that can significantly influence their overall environmental footprint.

Comparing the environmental impact of physical and digital preservation is complex and should not be approached as if it is a simple choice between one or the other. Each relies on infrastructure, energy sources, materials, and life cycle processes. Physical preservation typically depends on climate-controlled storage, conservation treatments, materials, and transport, while digital preservation relies on data centres, storage media, networking infrastructure, and ongoing computational activity. Both generate carbon emissions and other environmental impacts throughout their life cycles.

Environmental impact is shaped not only by the type of preservation, but by how that preservation is implemented. Factors such as storage density, redundancy, retention policies, refresh cycles, access patterns, and energy sources can have a greater influence on overall impact than whether collections are physical or digital. In many cases, decisions made for operational, legal, or access reasons, including maintaining multiple copies, supporting high levels of availability, or retaining material indefinitely, can amplify environmental costs unless explicitly managed.

A holistic approach is therefore required. Understanding the trade-offs between physical and digital preservation involves considering full life cycles, including infrastructure construction, energy consumption, material use, maintenance, migration, and end-of-life disposal. It also requires recognizing shifts in cost and impact from capital expenditure (such as buildings or equipment) to ongoing operational expenditure (such as energy and cloud services) and ensuring that these shifts are visible in sustainability planning. Furthermore, attempting to measure the carbon costs of physical preservation may require you to gain an understanding of the carbon footprint of your whole organization.

The table below outlines key factors that influence the environmental impact of physical and digital preservation. Its purpose is not to determine which approach is ‘more sustainable’, but to support informed decision-making, encourage proportional preservation strategies, and highlight opportunities to reduce environmental impact across both domains. Note that the environmental impacts described in this table go beyond just the carbon footprint. Also note that there is inevitably some physical infrastructure associated with digital preservation, thus environmental costs of physical archive stores (such as temperature control, lighting, security) will also apply to data centres. The table thus describes the differences, but also the similarities in the two approaches.

This table provides an illustration of how physical and digital preservation activities impact on the environment.

The carbon we generate by doing digital preservation has a real impact on our environment. Even 1 tonne of carbon causes polar ice to melt, and estimates are that between 640 and 2600 trees would need to be planted to offset this, but a more effective response than offsetting is to actively reduce your carbon footprint.

In order to decrease your carbon footprint, it is helpful to set targets, and to review whether, and how, you achieve them. Measuring your carbon footprint and benchmarking with similar organizations ideally should be an iterative part of your strategic planning process.

Here are some ideas of potential ways to reduce your carbon footprint:

• Change to a more carbon-neutral energy source or tariff.

• If appropriate, consider where your cloud data is stored. Regions with a high green energy component in their grid electricity will produce less carbon for the same storage than a region with a lower green energy component. You can track real-time electricity data worldwide at Electricity Maps – this is an interesting visual representation of regional differences, and it is updated every 15 minutes.

• Replace older processes and workflows with more efficient ones.

• When it becomes necessary to migrate to new storage, select storage with high sustainability standards (for example that consumes less energy or water, generates less heat, or where heat is captured and recycled for other uses).

• Schedule fixity checks during off-peak energy and network hours.

• Extend your hardware life cycle, or recycle or reuse old machines.

• Update your preservation policy (and other relevant policies) to reflect sustainability goals (for example you may introduce a policy that certain types of collections are stored on more sustainable storage).

• Review documentation and workflows with sustainability in mind. Consider whether any of the actions below are appropriate for your collections:

  • Appraise your collections, be selective, and delete material in line with your retention policy (see myth 8 in Myths and Legends).

  • Review the number of copies you preserve and consider whether this can be reduced.

  • Deduplicate and compress data where appropriate - note that some savings can be made without data loss using lossless forms of compression.

  • Decrease frequency of web archive captures or digital file transfers where appropriate.

  • Review your current use of file formats and storage media and understand their impacts on your carbon footprint.

  • Consider whether and when you will normalize or migrate file formats.

• Assess each cloud service provider’s carbon footprint as a whole when choosing a provider:

  • Do they report on their own carbon emissions?

  • Do they separate this into operational and embodied emissions?

  • Will they be able to deliver information about the carbon emissions of your use of their service specifically?

  • Do they use low carbon renewable power purchase agreements, or specific renewable energy purchases?

  • Do they have policies around waste and recycling?

• Take reduction targets into account during procurement exercises. When procuring cloud-based preservation systems and services, ensure that the storage system is documented and that carbon emissions can be measured and reported on (again, it is worth asking the question whether they will be able to provide information related to your use of the service specifically).

• Manage your users. Making preserved data easily discoverable and reusable is a core goal, but it can have unintended environmental consequences if data is downloaded, analysed, or stored unnecessarily.

  • Consider user guidance about the carbon footprint impact of different file formats.

  • Remove unnecessary images from your user interfaces.

  • Limit the number of search results that are returned to users.

  • Provide carbon impact indicators (e.g., ‘Estimated download impact: 0.5 kg CO₂’).

  • Encourage in-situ analysis.

  • Implement usage throttling (for example, limiting the speed at which data is shared across a network) or tiered access.

• Measure and understand your carbon footprint (using this toolkit and the Carbon Footprint Calculation Tool for example). This will help you see the areas of activity that generate the most carbon and thus provide insights into the areas where reductions may lead to the greatest impact. For example, if organizational travel for digital preservation purposes, generates the highest carbon footprint, then making some savings here, may be an impactful first step.

Note that as of March 2026 the NDSA Levels of Preservation now includes a leaf icon to illustrate those areas within the matrix where environmental sustainability considerations may influence and inform digital preservation decisions. Further information relating to these decision points can be found within the NDSA’s Environmental Sustainability Guide.

A note about offsetting

Some organizations use carbon offsetting as a means of reducing their impact. Carbon offsetting is about balancing, compensating, or neutralising the carbon emissions from a given activity by paying into a scheme or project that will reduce emissions (for example a tree planting scheme). There are various schemes accredited under the Gold Standard or the Verified Carbon Standard (VCS) which are international certification frameworks for carbon-offset projects. They aim to ensure that carbon credits represent real, measurable, and verifiable reductions or removals of greenhouse gas emissions.

Other organizations reject carbon offsetting entirely, arguing that it delays climate action and lacks credibility and impact (see for example a joint statement from the Environmental Coalition on Standards). It is widely recognized that reducing our carbon footprint shouldn’t be done purely by offsetting and that organizations should focus on reducing their own emissions as their first priority (see for example Net Zero-Aligned Offsetting Principles).

In short, the most impactful way an organization can reduce their carbon footprint is by understanding their carbon emissions and taking steps to reduce them.

Download the Carbon Footprint Calculation Tool to help record and calculate the carbon footprint of your digital preservation activities.

•  Carbon Footprint Calculation Tool– Excel spreadsheet (current version v1.0)

The DPC’s Carbon Footprint Task Force has developed an Excel-based spreadsheet tool to help you to calculate your carbon footprint. The tool is aligned with the generic service map described in Create a service map. The tool was built using the DIMPACT methodology. The methodology has been simplified for use by digital archives to estimate the impact of their own digital preservation activities.

Download a copy of the tool and look through the tabs of the spreadsheet to understand the kind of data you need to gather or estimate, and to plan how you will approach this exercise.

The spreadsheet tool can be a little daunting at first, but remember that you don’t need to think about everything at once. You may decide to focus on a certain area in the first instance and not fill out the whole template. Start small and build from there.

The following sections are designed to help you use the spreadsheet tool:

• Helpful tips for working with the Carbon Footprint Calculation Tool

• Gathering and entering your data

• Guidance on each of the sections of the spreadsheet

  • Summary

  • On Premise

  • In Cloud

  • Networking

  • Website use

  • Travel

  • Data and admin tabs

We are keen to provide practical guidance to help users of the toolkit understand and gather the necessary information. If you have tips and advice to share, or ideas to improve this guidance please do contact us at infoATdpconlineDOTorg.

How and where to start?

To minimize or reduce their impact on the climate, organizations should reduce their carbon emissions. First, they need to measure their current carbon footprint. Once that is understood, this information can be communicated to key stakeholders and used to plan how to reduce it through positive changes.

Calculating the carbon footprint is just one kind of environmental impact assessment, but it is especially relevant to digital archives. This is because greenhouse gas emissions from energy consumption and hardware production are likely to be far more significant than air/water pollution, radiation emissions or waste. Assess and include these additional impacts if they are a concern, but we recommend calculating the carbon footprint as a good way to start, since the amount of greenhouse gases that go into the atmosphere is a reasonable proxy for the scale of your global environmental impact.

Work through the steps below to get started with this exercise:

• Plan your project – before doing anything, it is important to understand what you are actually trying to accomplish – that will impact your approach and the decisions you make.

• Create a service map – whichever goals you are trying to achieve with your carbon footprint calculations, it is helpful to understand your organizational boundaries and the scope of your carbon calculations. Creating a service map will help you to do this.

To achieve organizational buy-in, it is essential that your managers and colleagues support the commitment to sustainability. So how do you start the conversation on this complex and sensitive topic?

The key steps are listening to, and connecting with, your colleagues and we list some tips below. If you would like to learn more, further helpful resources we recommend are:

• How to talk about sustainability with colleagues – a guide with tips specific to conversations about sustainability in the workplace.

• The secret to talking about climate change – a helpful video illustrating how to talk about climate change in any setting.

• The DPC’s Digital Preservation Advocacy Toolkit and Novice to Know-how training on Advocacy are helpful sources of advice on tackling the advocacy challenge. Though not specific to the climate crisis, they provide advice, practical tools and templates that can be adapted to any scenario and may be helpful to you in crafting and delivering persuasive messages to aid your conversations with colleagues.

Listen: Ask open-ended questions to learn more about what your management and colleagues care about, their concerns, and needs. They may need more factual information about climate impact or feel other larger organizations or governments should act first. They may not see what difference your organization can make in solving this huge global issue, and may even question climate change altogether. Listen to your colleagues and take them seriously. Use evidence-based figures, facts and arguments from authoritative sources, but do not forget emotions play a big part in how people react and respond.

Explore the connections: Try to find common ground you can build upon. What are the climate topics you and your colleagues are concerned about? For example, the servers that have been built in your neighbourhood but are solely used to support a big tech concern, not to serve the local community. You may find that climate awareness and measures to reduce impact might already be in place. Many organizations are recycling exhibition materials, encouraging employees to use reusable coffee cups, or motivating them to commute by public transport or bike. Build on this and explore ways to expand this thinking into the area of digital preservation. In the Netherlands, the Dutch Digital Heritage green team visited a museum exhibition about climate change and were inspired to start their own conversation about concerns they would like to tackle in their workplace.

Drivers: There are often political and organizational imperatives that may drive an organization to consider greenhouse gas emissions. The Paris Agreement in 2015 led to binding agreements to reduce emissions, so your organization may already be subject to legislation or expectations to report on, and reduce, its carbon footprint.

Find allies: Are there champions or experts in other parts of your organization you can work with? For example, many organizations are trying to become more sustainable and already have a sustainability office or team where potential allies could be found.

Use data: There is a lot of information on climate change, national and international climate goals and research, sustainability, and best practice. A lot of misinformation is out there too, so do your research, use authoritative sources (e.g., those produced by IPCC), and stay up to date as information changes.

Learn from others: Find good examples of where similar organizations have made progress in climate awareness, are taking climate actions themselves, and are communicating about their experience and effort to their users, stakeholders and the public. Organizations that have incorporated environmental goals and sustainability in their policy often report on how they achieved this (e.g., The Europeana climate action manifesto). You will also find some helpful examples in the Additional Resources section of this toolkit.

Be an ambassador and practise what you preach: Commute by bike, foot or public transport instead of by car, turn your computer and monitors off when you aren’t using them, replace your laptop and smartphone less frequently, and regularly clean up your own digital files and mailbox.

Show the benefits: More sustainable practices can lead to financial and reputational benefits. You can show the benefits of climate awareness by turning it into a business case that demonstrates the savings. Making hardware and software last longer is not only a financial gain, but also a carbon saver. Investments in green technology, such as solar panels, can lead to financial savings in the longer term. Being climate aware and taking responsibility can benefit your public image and help you connect with people who are motivated to protect our environment.

Hopefully, you will see some interest and engagement with the topic. See which colleagues are engaged and ask them if they would be willing to keep the conversation going. If they are, then now is the time to turn the conversation towards appropriate organizational goals and actions.