Yue Pan, Eli Blevis
Editor's Note: Before this article is published, the first Special Session on Cloud Computing, HCI, and Design: Sustainability and Social Impacts of the Second IEEE International Conference on Cloud Computing Technology and Science (CloudCom 2010) will have been held. This article is a shortened version of one that we will have presented in this context targeted at simply framing the issues of HCI and sustainability in the context of the trend toward cloud computing and in the perspective of design. The main session of the cloud computing conference will have rivaled the annual SIGCHI conferences in terms of competitive acceptance rates. Notwithstanding, few papers actually deal with HCI and sustainability issues outside of the special session. Few papers to date appear within HCI about cloud computing, especially in the context of sustainability. As a matter of consciousness in our community of HCI and interaction design, especially in the context of sustainability and HCI, the cloud trend is a part of our future and deserves our attention. In a subsequent "Sustainably Ours" column, we will describe the papers that appeared and the discussion that occurred in the special session.
Cloud computing is an important trendone with historical precedencethat has implications for the way in which people interact with digital technologies. Some of the notions now associated with cloud computing relate to efficiencies and energy use, marketing, and revenue and enterprise modelsthese notions are manifest as terms and phrases like "virtualization," "software as a service" (SaaS), "hardware as a service" (HaaS), and others. For many, cloud computing presents enterprise opportunity. For others, cloud computing may hold potentially dark implications from a sustainability perspective. For example, the organization Greenpeace writes:
"The cloud is growing at a time when climate change and reducing emissions from energy use is of paramount concern. With the growth of the cloud, however, comes an increasing demand for energy. For all of this content to be delivered to us in real time, virtual mountains of video, pictures and other data must be stored somewhere and be available for almost instantaneous access. That 'somewhere' is data centersmassive storage facilities that consume incredible amounts of energy." 
It would help to sort out what the sustainability and social implications of cloud computing actually are from a humanity-centered point of view. Do the promised efficiencies of cloud computing have implications for more sustainable practices, or will these efficiencies create greater resource and energy use and less sustainable behaviors corresponding to the possibility that greater capabilities induce greater use?
Figure 1 frames the problem of how to assess the environmental impacts of cloud computing with respect to the single issue of energy use. Over time, if cloud-computing practices increase and conventional distributed physical practices decrease, then the question is, will net energy use correspond to decreased, increased, or similar energy use than if cloud computing does not increase?
While one can measure the energy use of storing some unit of information in the virtual space of the cloud compared to storing that same unit of information in some number of possibly redundant physical locations, such measurement tells only part of the story. The issue is not so much one of faith in the efficiencies of less redundant, centralized storage and access, as much as it is one of how human behaviors will be transformed by a paradigm shift to cloud computing.
For example, suppose your favorite move is "Casablanca." What needs to be compared is the environmental cost of purchasing a DVD copy of the movie, downloading it once to a personal storage device, or streaming it on demand whenever you wish to watch it. There are many calculations involved in making this comparisonsuch as the number of times you watch "Casablanca," the way in which cloud-based inter-activity may change your viewing habits to perhaps expand your horizons to other films, the continuing frequent obsolescence of conventionally distributed, physical media-storage technologies and changes in bandwidth and resolution, the changes in how much media you consume in relation to increased availability and speed of access, and so on. Moreover, such calculations must be made in the presence of a constantly changing, dynamic technological and social state of being.
Perhaps Greenpeace's assessment is too simple in terms of enumerating the factors that are involved. Likely, the assessment of cloud service providers is too simple in enumerating the factors involved. The potential contribution of an HCI and design approach is to accept the complexity of the question at hand and view the problem as a true design problemthat is, a problem that must be informed by scientific measures but that ultimately comes down to best intuitions and predictions about how behaviors will change in the future as a result of the adoption of cloud-computing practices.
The idea behind cloud computing is simply to allow individuals to store and access their data in a virtually distributed waythat is to say, to free people of the requirement to maintain their own local, physical storage devices. The trend toward cloud computing has huge implications for interaction design and human mental models of interactivity. As Terrenghi and her colleagues noted in their 2010 CHI Work-in-Progress paper, "As resources are no longer physically stored on a specific device, it becomes clear that cloud computing influences the user mental model and experience with digital artifacts, especially in terms of organization and retrieval of information."  Cloud computing creates both the desire and holds the potential to prompt a consistent interface that fits situations at hand and yields a consistent cognitive mapping across a multiplicity of access devices.
Interaction design includes two fields: interface design, including physical device and software interactivitywhich pertains to human interactivity with computer devices and networksand service designwhich pertains to intangible products consisting of objects, people, networks, and brands. With respect to cloud computing, where the interface or device is a point of access to the data stored in different, amorphous "clouds," service design is an essential framing of the design of interconnectedness of these points of access .
With the growth of the cloud comes an increasing demand for energy. For all of this content to be delivered to us in real time, virtual mountains of video, pictures, and other data must be stored somewhere and be available for almost instantaneous access.
To date, there are not a lot of examples of interaction design targeted at cloud computing. Terrenghi et al.'s design for Cloudroom is based on smart-phones. Their idea is to provide an interactive application for visualization and management of sources in the cloud-computing paradigmin their words, "an ubiquitous access point to private and shared data." They have conducted some limited user studies. Some other examples are arguably outside of HCI and interaction design, but include studies by Guo et al. and Keahey et al. .
The Energy Star Program (www.energystar.gov) is not specifically associated with HCI literature, but it is nonetheless an important mechanism of awareness for people to understand the relative effects of certain systems compared to certain other systems. The Energy Star Program uses consumer labeling and even tax incentives to promote the reduction of energy consumption and greenhouse gas emissions.
The Energy Star Program sets an example for the HCI and design fields and other sustainability-related fields to address motivating questions such as:
- How can design raise awareness among general populations about the negative effects of greenhouse-gas emissions on the environment?
- How can design induce companies and industrial segments to direct resources toward energy efficiency?
- How can design promote an understanding among consumers about the link between what they buy and the environment, and how can consumer demand promote green corporate practices?
In considering the Energy Star Program with respect to cloud computing and HCI and design, we need to ask if similar forms of product labeling for environmentally conscious consumers can be created for the virtual products and services of cloud service providers. The idea of product labeling in the service of sustainability awareness has been taken up by Bonanni et al. and some others . There is an opportunity to apply some of this work in the context of cloud computing.
In addition to mapping, we record the following list of issues that frame the implications of cloud computing and sustainability in the perspective of HCI and design:
- What are the factors that affect energy use as consumers and enterprise shift to cloud computing?
- Does cloud computing induce sustainable or unsustainable behaviors?
- What is the role of HCI and interaction design in promoting sustainable practices in a cloud-based computing world?
- How does cloud computing relate to similar notions in HCI and pervasive computing, such as to Weiser's notions of dynamic ownership of computing devices? 
- Does cloud computing hold the possibility of inducing less disposability and increased durability of personal digital devices, or is the opposite more likely?
- What are the trade-offs in potential energy use between the widespread advent of cloud computing, compared with the continued use of widely distributed personal-computing resources, and is there a middle ground between these possibilities?
- Who can affect the kind of energy sources that are used to implement cloud computing apropos of sustainable energy choices? 
- Can cloud efficiencies and interactivity reduce energy use? 
The opportunities to design for cloud computing with sustainability, interaction design, and HCI principles in mind are many. Some ideas include:
Location-based cloud interactivity devicesIs it possible that different devices are motivated by the changes that will accrue in interactivity from the introduction of cloud computing? Perhaps there are differences in the design of devices based on mobile, home, or office contexts and the opportunity to create mobile, home, and office cloud stations. Are such devices needed, and if so, can these devices be designed with sustainability in mind from the start?
Cloud sustainability meters and social networkingCarbon calculators now abound and pervade to allow consumers to gauge their individual carbon footprint. The StepGreen (www.stepgreen.org) site targets individuals and provides carbon calculators as well as incorporating social networking with the goal of promoting sustainable energy use and other sustainable practices. StepGreen is the result of HCI research and design by Mankoff et al. . Similar design can be applied to the arena of cloud computing in the perspective of sustainability, HCI, and design.
The cloud computing trend signals an important paradigm shift in how people interact with digital materials, with potentially positive and negative implications for environmental and other sustainability effects. The shift to cloud computing is not much considered in the HCI and design literature to date. This article is the simplest possible framing of the issues that may be addressed.
2. Terrenghi, L., Serralheiro, K., Lang, T., and Richartz, M. Cloudroom: A conceptual model for managing data in space and time. Proc. of the 28th of the International Conference Extended Abstracts on Human Factors in Computing Systems (Atlanta, GA, Apr. 1015). ACM, New York, 2010.
3. Eriko Matsumura describes this notion of service apropos of interaction design and the cloud in his article "Interaction design; dispatches from Tokyo"; http://designdroplets.com/articles/interaction-design-dispatches-tokyo/
4. Guo, H., Chen, J., Wu, W., and Wang, W. Personalization as a service: The architecture and a case study. Proc. of the First international Workshop on Cloud Data Management (Hong Kong, Nov. 2). ACM, New York, 2009. Keahey, K., Figueiredo, R., Fortes, J., Freeman, T., and Tsugawa, M. Science clouds: Early experiences in cloud computing for scientific applications. Cloud Computing and Applications 2008. Chicago, IL, Oct. 2223.
5. Bonanni, L., Hockenberry, M., Zwarg, D., Csikszentmihalyi, C., and Ishii, H. Small business applications of sourcemap: A web tool for sustainable design and supply chain transparency. Proc. of the 28th International Conference on Human Factors in Computing Systems. (Atlanta, GA, Apr. 1015). ACM, New York, 2010.
7. Mankoff, J., Fussell, S.R, Dillahunt, T., Glaves, R., Grevet, C., Johnson, M., Matthews, D., Matthews, H. S., McGuire, R., Thompson, R., Shick, A., and Setlock, L. StepGreen.org: Increasing energy saving behaviors via social network. Proc. Fourth International AAAI Conference on Weblogs and Social Media. (Washington, D.C., May 2325). AAAI Publications, Menlo Park, CA, 2010.
Yue Pan is a doctoral student in the Human-Computer Interaction Design program at Indiana University's School of Informatics and Computing. She has a background in computer science, and her area of research is sustainable interaction design.
Eli Blevis is an associate professor of informatics in the Human-Computer Interaction Design program of the School of Informatics and Computing at Indiana University, Bloomington. His primary area of research is sustainable interaction design. This area of research and his core expertise are situated within the confluence of HCI as it owes to the computing and cognitive sciences, and design as it owes to the reflection of design criticism and the practice of critical design. His research also engages design theory, digital photography, and studio-based learning.
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