Laura U. Marks: Teaching online with a small carbon footprint
As we continue to plan for the fall, new teaching techniques are necessary as we shift classes online. But a significant challenge not addressed often enough while making this shift is the environmental consequences of online teaching, especially at such an increasing mass scale, which will add to an already significant, ever-growing streaming-media produced carbon footprint. Here are a number of "low-carbon online teaching tips" (in point-form) and some links that the SCA's Laura U. Marks presented during a recent set of online "workshops on remote learning" that the SCA ran for all of its faculty and staff. Some of these tips are drawn from the forthcoming publication, Media+Environment, by Marks, Joe Clark, Lucas Hilderbrand, Livingston, and Denise Oleksijczuk, as well as Mark's essay "Let's Deal with the Carbon Footprint of Streaming Media," recently published in the Afterimage: The Journal of Media Arts and Cultural Criticism.
- Streaming video’s electricity consumption is responsible for 1% of global warming!
- Health effects of high electromagnetic frequencies
- Corporate-driven streaming dependency
- Help students become mindful of the carbon footprint of streaming media and devise alternatives.
- Teach the environmental impact of the media at all levels — production, distribution, and consumption — into our curriculum
- Show The Shift Project ’s surprising charts
- Show Jason Livingston’s funny video
- Streaming audit: Ask students to note how many hours they stream a day, a week, a month, a year
- Calculate your carbon footprint with the formulas below or use a carbon footprint calculator
All online teaching happens on relatively small screens (laptops, computer monitors, phones and other devices), so high resolution is almost always not necessary
Asynchronous online teaching
- Audio-only sections: Lectures, dialogues, interviews. Students can listen away from the desk, even while walking or exercising
- Consider stills rather than video clips
- Video: Use short clips
- Consider resolution needs: 240 or 340 Kpbs bitrate is adequate for informational purposes
Students watching media independently
- View in groups if possible — always better and produces a smaller footprint
- For multiple viewings, it's best to download source media, but copyright issues may arise. Suggest that if SFU Library has purchased the movie, we are within our rights to let students download it for study purposes.
- Turn off HD and use the lowest resolution necessary
Synchronous online teaching
- Use short clips and set resolution as necessary or consider stills rather than video
- It’s more energy efficient to share a video on a video conferencing platform, such as Zoom, via screen-share than for each student to stream it separately
- Share video and audio from the original source (e.g. YouTube, Criterion Collection through library)
- Note: In Zoom, make sure to click “Share computer sound” and “Optimize screen share for audio” every time! Details HERE
- If possible, choose media already available online, rather than uploading something new — YouTube’s local data centers make this more efficient for international viewers.
- Invite students to sign in with video, then switch to portrait with their name displayed
- Suggest students experiment with minimizing the frame in speaker view and gallery view
- More tips HERE
Teaching media makers
- Consider making versions for different platforms: high resolution for theaters, lower for online.
- Teach small-file video making — Stills and sound, low frame rate, compression, animation; but splurge on sound. Compressed movies look best with:
- slow or still camera movement
- shallow focus
Find more tips on the Small File Media Festival site.
Lucas Hilderbrand’s streaming acknowledgment
Streaming media has a significant carbon footprint due to the high energy usage necessary for data storage on servers, for transmission, and for playback. The scale of emissions depends on both the energy sources (fossil fuels create more impact than renewable ones) and the amount of data streamed (higher definition streams use more energy than standard definition ones, and video requires more energy than audio). Although migration to renewable energy sources has improved, demand for streaming content and bandwidth has accelerated even more. You can reduce your carbon footprint by reducing how much you stream, by reducing the resolution of your playback, by dimming your device, and by lobbying your energy provider and government regulators to switch to renewable energy sources. Broadcast sources (such as using the radio), tangible media (such as vinyl records and DVDs), and collective viewing (such as in a movie theater) have a lower carbon footprint than everyone individually streaming music and audiovisual media. (In Marks, Clark, Hilderbrand, Livingston, and Oleksiczjuk, forthcoming, Media+Environment)
Joseph Clark’s energy intensity calculator (in Media+Environment)
- Multiply file size in gigabytes by 5 kWh/GB to get energy in kilowatts.
Example: Streaming a high resolution copy of a 10 minute newsreel (500MB) is about 2.5 kWh. That, according to the owner’s manual for Joe’s clothes dryer, is about the equivalent of drying one load of laundry.
Marks, Makonin, and Rodriguez-Silva: Calculating the carbon footprint of a given streaming program (in Media+Environment)
Length of the streaming video in hours
- x gigabytes per hour for a given resolution (Summerson 2018) 
- 480 pixels: ~ 792 MB/hour
- 720p: ~ 1.3 GB/hour
- 1080p: ~ 1.9 – 2.55 GB/hour
- 1440p: ~ 2.8 GB/hour
- 4K: ~ 3.5 – 7 GB/hour
- x energy intensity: 4.91 kWh/GB
- x number of unique viewers
- x 0.007 metric tons of CO2 (Environmental Protection Agency 2020)
- = carbon footprint.
Longer article: Let's Deal with the Carbon Footprint of Streaming Media, Afterimage (Volume 47, Issue 2 | June 2020)
 Summerson uses Netflix’s streaming bitrate. Note: Netflix is more energy efficient than other platforms.