# Cloud sustainability
The discipline of sustainability addresses the long-term environmental, economic, and societal impact of your business activities. The [United Nations World Commission on Environment and Development](https://www.un.org/en/academic-impact/sustainability) defines sustainable development as “development that meets the needs of the present without compromising the ability of future generations to meet their own needs.” Your business or organization can have negative environmental impacts like direct or indirect carbon emissions, unrecyclable waste, and damage to shared resources like clean water.
When building cloud workloads, the practice of sustainability is understanding the impacts of the services used, quantifying impacts through the entire workload lifecycle, and applying design principles and best practices to reduce these impacts. This document focuses on environmental impacts, especially energy consumption and efficiency, since they are important levers for architects to inform direct action to reduce resource usage.
When focusing on environmental impacts, you should understand how these impacts are typically accounted for and the follow-on impacts to your organization’s own emissions accounting. The [Greenhouse Gas Protocol](https://ghgprotocol.org/) organizes carbon emissions into the following scopes, along with relevant emission examples within each scope for a cloud provider such as AWS:
+ **Scope 1:** All direct emissions from the activities of an organization or under its control. For example, fuel combustion by data center backup generators.
+ **Scope 2:** Indirect emissions from electricity purchased and used to power data centers and other facilities. For example, emissions from commercial power generation.
+ **Scope 3:** All other indirect emissions from activities of an organization from sources it doesn’t control. AWS examples include emissions related to data center construction, and the manufacture and transportation of IT hardware deployed in data centers.
From an AWS customer perspective, emissions from your workloads running on AWS are accounted for as indirect emissions, and part of your Scope 3 emissions. Each workload deployed generates a fraction of the total AWS emissions from each of the previous scopes. The actual amount varies per workload and depends on several factors including the AWS services used, the energy consumed by those services, the carbon intensity of the electric grids serving the AWS data centers where they run, and the AWS procurement of renewable energy.
This document first describes a shared responsibility model for environmental sustainability, and then provides architectural best practices so you can minimize the impact of your workloads by reducing the total resources required for them to run in AWS data centers.
# The shared responsibility model
Environmental sustainability is a shared responsibility between customers and AWS.
+ AWS is responsible for optimizing the sustainability *of* the cloud – delivering efficient, shared infrastructure, water stewardship, and sourcing renewable power.
+ Customers are responsible for sustainability *in* the cloud – optimizing workloads and resource utilization, and minimizing the total resources required to be deployed for your workloads.
![\[Diagram showing the AWS shared responsibility model.\]](http://docs.aws.amazon.com/wellarchitected/latest/sustainability-pillar/images/sustainability-in-the-cloud.jpeg)
## Sustainability of the cloud
Cloud providers have a lower carbon footprint and are more energy efficient than typical on-premises alternatives because they invest in efficient power and cooling technology, operate energy efficient server populations, and achieve high server utilization rates. Cloud workloads reduce impact by taking advantage of shared resources, such as networking, power, cooling, and physical facilities. You can migrate your cloud workloads to more efficient technologies as they become available and use cloud-based services to transform your workloads for better sustainability.
### Resources
+ [The Carbon Reduction Opportunity of Moving to Amazon Web Services](https://sustainability.aboutamazon.com/carbon_reduction_aws.pdf)
+ [AWS enables sustainability solutions](https://aws.amazon.com/sustainability/)
## Sustainability in the cloud
Sustainability in the cloud is a continuous effort focused primarily on energy reduction and efficiency across all components of a workload by achieving the maximum benefit from the resources provisioned and minimizing the total resources required. This effort can range from the initial selection of an efficient programming language, adoption of modern algorithms, use of efficient data storage techniques, deploying to correctly sized and efficient compute infrastructure, and minimizing requirements for high-powered end-user hardware.
# Sustainability through the cloud
In addition to minimizing the impact of workloads that you’ve deployed, you can use the AWS Cloud to run workloads designed to support your wider sustainability challenges. Examples of these challenges include reducing carbon emissions, lowering energy consumption, recycling water, or reducing waste in other areas of your business or organization.
Sustainability *through* the cloud is when you use AWS technology to solve a broader sustainability challenge. For example, you can use a machine learning service to detect abnormal behavior in industrial machinery. Using this detection data, you can conduct preventative maintenance to reduce the risk of environmental incidents caused by unexpected equipment failures and ensure that the machinery continues to operate at peak efficiency.
# Design principles for sustainability in the cloud
Apply these design principles when architecting your cloud workloads to maximize sustainability and minimize impact.
+ **Understand your impact:** Measure the impact of your cloud workload and model the future impact of your workload. Include all sources of impact, including impacts resulting from customer use of your products, and impacts resulting from their eventual decommissioning and retirement. Compare the productive output with the total impact of your cloud workloads by reviewing the resources and emissions required per unit of work. Use this data to establish key performance indicators (KPIs), evaluate ways to improve productivity while reducing impact, and estimate the impact of proposed changes over time.
+ **Establish sustainability goals:** For each cloud workload, establish long-term sustainability goals such as reducing the compute and storage resources required per transaction. Model the return on investment of sustainability improvements for existing workloads, and give owners the resources they need to invest in sustainability goals. Plan for growth, and architect your workloads so that growth results in reduced impact intensity measured against an appropriate unit, such as per user or per transaction. Goals help you support the wider sustainability goals of your business or organization, identify regressions, and prioritize areas of potential improvement.
+ **Maximize utilization:** Right-size workloads and implement efficient design to ensure high utilization and maximize the energy efficiency of the underlying hardware. Two hosts running at 30% utilization are less efficient than one host running at 60% due to baseline power consumption per host. At the same time, eliminate or minimize idle resources, processing, and storage to reduce the total energy required to power your workload.
+ **Anticipate and adopt new, more efficient hardware and software offerings:** Support the upstream improvements your partners and suppliers make to help you reduce the impact of your cloud workloads. Continually monitor and evaluate new, more efficient hardware and software offerings. Design for flexibility to allow for the rapid adoption of new efficient technologies.
+ **Use managed services:** Sharing services across a broad customer base helps maximize resource utilization, which reduces the amount of infrastructure needed to support cloud workloads. For example, customers can share the impact of common data center components like power and networking by migrating workloads to the AWS Cloud and adopting managed services, such as AWS Fargate for serverless containers, where AWS operates at scale and is responsible for their efficient operation. Use managed services that can help minimize your impact, such as automatically moving infrequently accessed data to cold storage with Amazon S3 Lifecycle configurations or Amazon EC2 Auto Scaling to adjust capacity to meet demand.
+ **Reduce the downstream impact of your cloud workloads:** Reduce the amount of energy or resources required to use your services. Reduce or eliminate the need for customers to upgrade their devices to use your services. Test using device farms to understand expected impact and test with customers to understand the actual impact from using your services.