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The term ‘carbon footprint’ is a bit misleading. It is not carbon that is being measured, or that carbon is doing the harm to the planet in the form of global heating and worsening the climate crisis. Carbon is the chemical in coal and in diamonds and the most common element in the human body. It is essential for all life.

The damage to the climate is caused by a number of gases collectively known as greenhouse gases (often shortened to GHGs). These are a mix of carbon dioxide (CO2), methane (CH4), Nitrous oxide (N2O), and fluorinated gases. Fluorinated gases include those used in fridges and freezers, or as propellants in many inhalers used by asthmatics or in aluminum production or electrical transmission.

Each gas causes a different amount of global heating – known as the global warming potential (GWP). The GWP of carbon dioxide is 1 and is the base that every other gas is measured against. Methane has a GWP of 80- which means that one molecule of methane causes the same level of heating equivalent to 80 molecules of carbon dioxide. Nitrous oxide is even worse with a GWP of 273 (or one molecule of N20 is the same as 273 molecules of CO2) and some of the fluorinated gases, their GWPs are measured in the thousands or tens of thousands.

Knowing these conversion factors means each of these gases can be converted into a single ‘currency’ – or common value – the equivalent amount of carbon dioxide. The damage caused by each of the greenhouse gases can be expressed as ‘CO2e’ or ‘carbon dioxide equivalence’. One kilogram of methane is the same as 80 kg carbon dioxide equivalent or 80 kg CO2e.

A carbon footprint is the total amount of all the greenhouse gases generated and emitted by an individual, a process, a company or a nation. We now have a common term that we can use – CO2e – but how does that help find a carbon footprint? All of our activities use one or more of the greenhouse gases. An easy example is thinking of driving a car which uses 1 litre of petrol. Petrol is made from chains of carbon and hydrogen which generates carbon dioxide when combusted in the engine. The amount of carbon is known, so the amount of carbon dioxide can be calculated and measured. If the distance travelled is known, the amount of emissions per mile can be calculated. These conversion factors are produced annually and published by the government. Here, it can be found that for each mile travelled in a medium sized petrol car, 302 gCO2e is produced. For every 1,000 miles travelled, 302 kg CO2e is emitted – or a third of a ton.

Similar conversion factors are available for electricity. In the UK, every kWh generated produces 212 gCO2e. A full kettle uses 0.25 kWh to boil (or 54gCO2e) or an average UK house uses about 3,000 kWh electricity a year – or 636 kg CO2e per year. For gas, an average UK home uses in the region of 12,000 kWh which is 2,436 kg CO2e per year for space and water heating. Equally, all other goods and services can also be converted into ‘amount of carbon emissions’. There are a number of online carbon calculators for measuring our personal footprint. One of the best is by Small World Consulting. 

However, carbon emissions are not the only bad guy in town. Biodiversity is going to be a far bigger problem, as is collapse of the life-supporting ecosystems the natural world currently provides us. There are ‘forever chemicals’ in our soils, water and air, plastic particles found from the bottom of the oceans to the tops of the world as well as in our lungs and blood streams, ocean acidification, air pollution and many others. Living within the planetary boundaries are well summarised by Kate Raworth in her book Doughnut Economics, and in her TED videos.

Previously, people thought sustainability was the intersect between the three pillars of society, the environment and the economy. This view has been superseded by the nested model of sustainability (Fig 1). This highlights that without a functioning living world, there will not be the opportunity to have a functional society. Without a society, there cannot be an economy for the latter unequivocally depends on the former. The traditional approach that the economy is somehow more essential that the other two pillars is demonstrably false.

There are voices from multiple sectors who are increasingly vocal about the problem the planet faces with the climate crisis – and how it is everyone’s responsibility to take action as everyone will be affected.They range from Andrew Bailey, governor Bank of England, who said we know now [climate change] is coming, so we can identify where risks will arise and start managing them in advance. Compared to the financial crisis and the pandemic, the risks from climate change are even bigger and more complex to manage. And acting now gives us the best opportunity to manage those risks.”, to the Ministry of Defence who said ‘there is a clear and present danger that afflicts all of us, every region of the world, every part of society. That is the threat posed by climate change’ From health, Sir Simon Stevens former Chief Exec of the NHS said, ‘Undoubtedly climate change poses the most profound long term threat to threat to the health of the nation… avoidable deaths are happening now – not in 2025 or 2050 – we need to act now’.

The issue of the climate crisis is well recognised, but what about urgency to act? The recently published 6th report from the International Panel for Climate Change, released in spring 2022, emphasised that CO2e emissions must peak no later than 2025 for the planet to stay within a 1.5’c temperature rise. Sarah Burch, a lead author, said ‘We can’t reach our broader sustainable development goals (vibrant nature, clean water, no poverty, health communities etc) if we don’t address climate change. It just won’t work. All sectors identify both the scale of the challenge and the speed of change required.

How can I be optimistic?

Climate change is a real problem, recognised across all business sectors and all countries across the globe, but there is still hope. There is a window of opportunity but is it closing fast. Through a combined global effort, the progression towards a runaway climate with soaring temperatures, passing the irreversible tipping points of ice cap loss and rising sea levels, can be avoided.

Resources and guides are increasingly available. Organisations such as the Science Based Targets Initiative  or the Carbon Trust among others aid companies and corporations to set science based targets, and understand their role in protecting the natural world from further harm and the actions they can start to do today.

By understanding what a carbon footprint is, recognising the sources of greenhouse gas emissions through our personal and professional lives, positive action to reduce the harm being caused to the natural world is possible. Many would even say essential.