British Sign language sign for carbon sink

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How we designed sign language for climate science

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The climate crisis affects everyone. To tackle it, everyone needs to be able to talk about it. A team of deaf scientists and sign linguists are making important conversations about the future of the planet more accessible to the deaf community.

Originally published in The Conversation as “How we developed sign language for ten of the trickiest climate terms”, this article is intended as British sign language-first in video form with the translation written in full beneath.

British Sign Language Alphabet on a White Background
British Sign Language Alphabet on a White Background
How we developed sign language for ten of the trickiest climate terms, presented in BSL by author Audrey Cameron.

Creating British sign language (BSL) signs for abstract climate concepts is very different from tangible objects like animals, but the process is equally fascinating. While a rabbit sign might directly represent its physical appearance, climate concepts require a deep understanding of scientific processes to create meaningful visual representations.

Our sign development process involves a team of 12 experts at the University of Edinburgh, including deaf scientists, deaf educators and sign linguists. Earlier this year, our Royal Society-funded project developed 400 environmental science signs. Rather than literally translating English words, we focused on visually representing the underlying concepts for these terms.

For example, the sign for “carbon footprint” doesn’t attempt to combine signs for carbon and footprint. Instead, it shows carbon emissions being released into the atmosphere, with the speed of movement indicating emission levels. This approach makes complex concepts immediately understandable, eliminating the need for time-consuming finger-spelling.

New signs go through rigorous feedback from team members and deaf students before being approved and added to the Scottish Sensory Centre BSL online glossary. Each sign is filmed professionally and supplemented with definitions in BSL.

This visual approach to scientific concepts makes BSL more efficient and helps deeper understanding. Users don’t just learn a word, they see how the process works.

Here are ten crucial climate terms with explanations of how we designed their BSL signs:

1. Carbon footprint

The BSL sign for carbon footprint.

The concept of carbon emissions starts with left hand forming a “C” shape to represent carbon, while the right hand shows the release of carbon into the atmosphere. The movement of the right hand indicates the varying levels of carbon emissions: a rapid upward movement represents high emissions from an activity, while a slower downward movement shows lower emissions.

Rather than literally translating the English metaphor of a footprint, this sign focuses on conveying the actual meaning: measuring the amount of carbon released by different activities.

2. Carbon offsetting

The BSL sign for carbon offsetting.

This sign visually represents the concept of reducing atmospheric carbon to sustainable levels. The sign begins with a “C” handshape to represent carbon. Then, using both hands, it demonstrates the carbon imbalance in the atmosphere.

The sign shows how current carbon levels are higher than desired. It illustrates the action of compressing these levels to an optimal amount by offsetting – by planting more trees, for example.

3. Carbon sequestration

The BSL sign for carbon sequestration.

The BSL sign for carbon sequestration visually represents the process of capturing and storing atmospheric carbon dioxide (CO₂) into the Earth. The sign begins by fingerspelling “C-O-2”. Then, both hands move down to show the capturing and pulling CO₂ downwards.

This sequestration process can occur naturally (by trees absorbing CO₂) or through human-engineered technology solutions.

4. Carbon capture and storage

The BSL sign for carbon capture and storage.

The process of capturing CO₂ from industrial processes and burning fossil fuels, then storing it underground is represented by a sign that combines elements from two others.

It begins with carbon footprint, showing carbon dioxide being released into the atmosphere (from industrial processes and fossil fuel burning). This is followed by the movement from carbon sequestration, demonstrating the rapid capture and downward pulling motion that represents storing the CO₂ in underground geological formations.

5. Greenhouse gases

The BSL sign for greenhouse gases.

This sign visually represents how greenhouse gases interact with sunlight in Earth’s atmosphere. Both hands begin in circular shapes, making moving gestures to show the presence of gases in the atmosphere (such as CO₂, methane, water vapour and nitrous oxide).

The left hand changes to a flat position to represent the Earth’s surface, while the right hand changes to just an extended index finger that moves downward and bounces back up towards the left hand. This demonstrates how sunlight is reflected from the Earth’s surface and trapped by greenhouse gases.

6. Global warming

The BSL sign for global warming.

To explain the increasing temperature of Earth, both hands show the shape of Earth, then the right hand moves up towards and across the forehead to indicate heat.

Next, the two index fingers are positioned together. The left index finger is vertical to represent a thermometer, while the horizontal right index finger moves upwards to show rising temperature. The speed of upward movement can be adjusted to indicate how rapidly Earth is warming up.

7. Climate change

The BSL sign for climate change.

This is another compound sign that builds on the concept of climate. It begins with the climate sign, with both hands making cloud-like movements to represent weather conditions. Then, the hands make a turning motion to represent change, showing how weather patterns are shifting over time.

This visual combination effectively represents the long-term changes in Earth’s climate systems. The speed of the turning movement can be adjusted to show whether the climate change is gradual or dramatic. A slower movement indicates gradual change, while a faster movement represents more drastic changes.

8. Carbon sink

The BSL sign for carbon sink.

Beginning with a “C” handshape to represent carbon, this sign represents how Earth naturally absorbs CO₂ from the atmosphere. Next, the hands show this carbon being absorbed downward into natural storage areas like oceans, soil, plants and peat bogs. The downward movement of the “C” handshape shows how these natural systems capture and store atmospheric CO₂.

9. Sustainability

The BSL sign for sustainability.

This sign represents the ability to maintain a balanced system. The sign begins with two flat hands, palms facing down in a horizontal position, moving up and down slowly to demonstrate a stable state. Then, the right hand moves up to the nose, with the index finger and thumb pinching together – this means “ability” and indicates that this balanced state can be maintained over time.

10. Tipping point

The BSL sign for tipping point.

A tipping point is the critical moment when environmental changes become irreversible. This BSL term begins with two clenched fists together, twisting in opposite directions to show a crucial change taking place. This is followed by two flat hands, palms facing down in a horizontal position, moving up and down to demonstrate the unstable state of the system.

A concerned facial expression accompanies the sign to convey the seriousness of reaching this environmental threshold. The sign can be extended to show what happens after passing the tipping point by raising the right hand high, demonstrating the irreversible environmental damage that follows.

This article was originally published in the Conversation on 11 November 2024.

Image credit: BSL alphabet – pamela_d_mcadams/Getty