Here’s five mission-critical facts to help coffee people navigate the issues, understand the terms and identify a suitable course of action.
1. How do we know the world is warming?
In the 1960s scientists noticed the earth was getting hotter.
Technology had developed to better measure, calculate and understand weather patterns and atmospheric temperatures. The more scientists measured, the more they became certain temperatures were steadily increasing.
Today, we now have a much better data. This chart shows how temperatures have increased in the UK since 1900. The darker the red bar, the warmer the year. It is now consistently around 1ºC warmer than it was 100 years ago.
The UK’s situation is representative of the global picture.
NASA, the American space agency, has done great work to measuring temperature increases. Their data show global temperatures are also around ~1°C hotter than 1880 (that’s almost 2° Fahrenheit warmer!).
2. Why is the world warming?
The earth is enveloped in a protective layer of gas called the atmosphere.
The blend of gases in the atmosphere enables life on earth. For example, when sunlight enters the atmosphere it warms the earth. For millennia this worked in balance: heat arrives from the sun, warms the atmosphere to keep humanity alive and then bounces back into space.
The problem started 250 years ago. During the industrial revolution humanity started burning carbon-rich fuels, such as coal and wood, to power new technologies like steam-powered factories and trains.
When carbon-rich fuels burn, they create heat. But some of the carbon is freed to mix with the surrounding oxygen. In higher temperatures, carbon and oxygen are more likely bind together to create a carbon dioxide molecule.
Carbon dioxide is a gas made from one carbon atom and two oxygen atoms – so it can be written as CO₂.
As the subscript ‘2’ is tricky to type, so sometimes it’s casually written as CO2.
Contemporary life has been made possible by burning carbon-rich fuels. While people may no longer travel by steam train, we burn a lot of petrol and gas for transport, heating and cooking. Plus, many industries, technologies and and materials are possible by burning carbon-rich fuels.
This chart shows the quantity of carbon dioxide in the atmosphere over millennia. As you can see, the current CO₂ levels are very high – and still increasing.
Carbon dioxide is more insulating than other gases in the atmosphere. While some carbon dioxide in the atmosphere is both natural and necessary, the current levels of carbon dioxide trap too much of the sun’s heat. The increasing temperatures change weather patterns, a phenomenon called ‘climate change’.
Despite all the discussion over temperatures getting warmer, the cause was always clear. In fact, it was predicted hundreds of years ago by a Swedish scientist called Svante Arrhenius whose genius was to understand ahead of time that increasing carbon dioxide emissions would cause a ‘greenhouse effect’.
3. What is a carbon footprint?
Scientists now understand there are many insulating gases with artificially high levels in the atmosphere. We call all these ‘greenhouse gases’.
For example, another common greenhouse gas is methane.
Each greenhouse gas has a unique insulation level and lifespan. So, the maths to calculate the total greenhouse effect can get complicated.
To keep things simple, greenhouse gases are often converted to the amount of carbon dioxide that would be required to deliver the same warming effect.
For example, methane is 25 times more potent over its lifespan than carbon dioxide. So, 1 Kg of methane is equivalent to 25 Kg of carbon dioxide.
This is said as ’25 kilograms carbon dioxide equivalent’ and written as 25 Kg CO₂e.
It’s very convenient to be able to communicate a total carbon footprint with a single unit: CO₂e. And again, as the subscript 2 can be tricky to type, it is sometimes written as ’25 Kg CO2e’.
There’s no need to be pedantic when communicating carbon footprints, but it’s good to be precise. For example, in a United Baristas article we would typically write, ‘coffee has a carbon footprint of ~2 Kg CO₂e per Kg’ or ‘one kilogram of coffee has a carbon footprint of about two kilograms CO₂e’. This way it’s clear that there are other greenhouse gases in coffee’s carbon footprint. And that all the greenhouses gases are included in the figure.
However, it’s commonplace to communicate a carbon footprint as ‘2 Kg CO2’ and even say that a coffee has ‘carbon emissions of about 2 Kg’ or even ‘2 Kg carbon’. While these other ways of communicating carbon footprints are less good, we still occasionally use them – especially on social media or in conversation.
4. The carbon challenge
To prevent the earth from getting too hot for people to live, we need to reduce the quantity of greenhouse gases emitted into the atmosphere.
Carbon dioxide stays in the earth’s atmosphere for 300 – 1,000 years. That means that the first carbon dioxide emitted by coal-fired factories and steam trains at the beginning of the industrial revolution is finally breaking down.
The number-crunching scientists estimate that, even after the current carbon cutting commitments, humanity will emit 17 – 20 billion tonnes too much CO₂e over the coming 10 years to limit warming to the original target of 1.5 ℃.
With the 1.5 ℃ target now unreachable, a new goal of a temporary 2 ℃ increase is commonplace. To reach either of these targets, massive carbon emission reductions are necessary. In fact, industrial carbon emissions will need to be eliminated globally between 2040 and 2050.
At present, the average UK resident has a carbon footprint of about six tonnes per year. Emissions per person have been steadily falling, largely as electricity generation shifted first from coal to gas, and now to solar, wind and nuclear.
However, some emissions will be too tricky to cut. It’s estimated that the typical UK resident will cut their footprint to ~1.5 tonnes by 2040. The remaining carbon emissions will need to be ‘offset’ with carbon capture to reach ‘net zero’.
5. Coffee contributes to, and is impacted by, climate change
Each flat white has a carbon footprint of ~250 grams. While at origin, warmer temperatures and changes in rainfall adversely impacting coffee production. By making several key, cost-effective changes it is possible to cut a flat white’s footprint to less than 50 grams.
By understanding the causes of coffee’s carbon footprint and identity the actions necessary to cut it, it’s possible to both safeguard the future of specialty coffee and equip you to cut your total carbon footprint.
