Research: Sandwiches Contribute to Global Warming

Category: Science/Environment


Unlocking Word Meanings

Read the following words/expressions found in today’s article.

  1. emit / ɪˈmɪt / (v) – to release

    The factory emits black smoke.

  2. alter / ˈɔl tər / (v) – to change or adjust

    The company is encouraging employees to alter their work habits so they can cut back on resources.

  3. prolong / prəˈlɔŋ, -ˈlɒŋ / (v) – to make something last longer

    We can prolong the life of plants by watering them regularly.

  4. shelf life / ʃɛlf laɪf / (n) – the length of time in which an item is still useable or fit for consumption

    Honey has a long shelf life; it can last for two years without going bad.

  5. substitute / ˈsʌb stɪˌtut, -ˌtyut / (n) – a person/thing who/that can replace another

    Oats are a healthy substitute for rice.


Read the text below.

Sandwiches add to carbon dioxide (CO2) emissions, a new study reveals.

Researchers from the University of Manchester measured the carbon footprint—the amount of CO2 emissions—of 40 different sandwich types that were either homemade or ready-made. They examined the sandwich-making process, which involves agricultural production, processing of ingredients, packaging, distribution, refrigeration, and food waste disposal.

Based on the findings, the production and consumption of 11.5 billion sandwiches—the annual average in the UK—emits the same amount of CO2 as 8.6 million cars.

Agricultural production and processing of ingredients like cheese and meat were found to be the leading contributors to a sandwich’s carbon footprint, which ranges from 37% to 67% CO2 equivalent—the unit of measurement for carbon footprints. Refrigeration also contributes a fairly large amount at 25%.

Study results further revealed that sandwiches that contain prawns, cheese, and processed meat like ham, bacon, and sausages are the most harmful to the environment, even more so if these are ready-made.

According to the researchers, altering sandwich recipes, packaging, and waste disposal can reduce the carbon footprint of sandwiches by 50%. The British Sandwich Association also suggested prolonging the shelf life of sandwiches to lower waste by over 2,000 tonnes a year. Researcher Adisa Azapagic attested that ready-made sandwiches are still safe for consumption even beyond the indicated expiration date.

Meanwhile, in response to the study’s results, Friends of the Earth, a global network of environmental organizations, is urging businesses to come up with more eco-friendly, plant-based lunch substitutes for sandwiches, especially those that use processed cheese and meat.

Viewpoint Discussion

Enjoy a discussion with your tutor.

Discussion A

• Do you think you need to alter your food choices after reading the article? Why or why not?
• Aside from sandwiches, what other food do you think should be examined for their carbon footprint in the future?

Discussion B

• What do you think is the biggest carbon footprint contributor (e.g. factories, developed countries)? Defend your answer.
• How can you reduce your own carbon footprint? Share your ideas.