These terms are thrown around all the time and what they all mean can get confusing, let’s start with what a greenhouse gas (GHG) is. A GHG is a gas that absorbs and re-emits heat within the Earth’s atmosphere and thereby keeps the planet’s atmosphere warmer than it would otherwise be. The primary greenhouse gasses in the Earth’s atmosphere are water vapour, carbon dioxide (CO₂), methane (CH₄), nitrous oxide (N₂O) and ozone. (Mathew Brander, 2012)

Why do we care about carbon dioxide (CO₂) and what it is? CO₂ is the most common GHG emitted through human activities in terms of quantities and total impact on global warming and therefore we should care about it. The burning of fossil fuels to create power, transportation and deforestation are just some examples of human activities which emit CO₂. (Mathew Brander, 2012)

How about CO₂e? This looks the same as CO₂, so what’s the difference? Well, CO₂e is shorthand for carbon dioxide equivalent and is for comparing various greenhouse gasses in a common unit. For any quantity and type of GHG, CO₂e represents the amount of CO₂ which would have been the equivalent global warming impact. (Welsh Government, 2021) To express a quantity of a GHG as CO₂e, the amount of the GHG can be multiplied by its global warming potential. For example, if 1kg of methane is emitted, then this can be expressed as 25kg of CO₂e (1kg of CH₄ × 25 = 25kg CO₂e). (Mathew Brander, 2012)

The Oxford English Dictionary defines a climate emergency as a situation in which urgent action is required to reduce or halt climate change and avoid potentially irreversible environmental damage resulting from it. In 2019, the UK declared a national climate emergency, following other declarations made by municipalities across the UK, Bristol City Council being the first in 2018, not only in the UK but in Europe too. (Brown L. , 2019)

The reason this declaration was such a monumental step for the UK is because it finally acknowledged the severe effects of climate change, which are inevitable without change. Statistics and examples speak loudest, so here are just a few to demonstrate the catastrophic effects if we do nothing. The last time our planet was hotter than now was at least 125,000 years ago. Global temperatures are projected to surpass the irreversible threshold by 2027 if nothing is done, this will and has led to significantly more periods of extreme heat. Historically, a heatwave was a once-a-decade event, now this happens 2.8 times a decade and in just 6-11 years could be happening 4.1 times a decade. Heatwaves have been killing hundreds and thousands of people as well as billions of sea creatures. In 2021, Germany and China have seen astounding floods, wildfires of extreme magnitude have burned through Canada, California and Greece, and rain for the first time has fallen rather than snow at the summit of a rapidly melting Greenland. At the current rate, by 2050, 216 million people, mostly from developing countries, will be forced to flee the impacts of climate change. Radical action is needed and was needed long before today. (The Guardian, 2021)

These terms are used all the time as if they were interchangeable, but this isn’t the case. Carbon neutral means achieving a state in which the net amount of CO₂e emitted into the atmosphere is reduced to zero because it is balanced by actions to reduce or offset these emissions. If the amount of CO₂e reduced or offset is more than the net amount emitted into the atmosphere, then this means carbon negative. Whilst net zero means making changes to reduce greenhouse gas emissions to the lowest amount and offsetting as a last resort. The offsetting will be done to counteract the essential emissions once all emission reduction measures have been implemented. (Chartier, 2021)

The reason this declaration was such a monumental step for the UK is because it finally acknowledged the severe effects of climate change, which are inevitable without change. Statistics and examples speak loudest, so here are just a few to demonstrate the catastrophic effects if we do nothing. The last time our planet was hotter than now was at least 125,000 years ago. Global temperatures are projected to surpass the irreversible threshold by 2027 if nothing is done, this will and has led to significantly more periods of extreme heat. Historically, a heatwave was a once-a-decade event, now this happens 2.8 times a decade and in just 6-11 years could be happening 4.1 times a decade. Heatwaves have been killing hundreds and thousands of people as well as billions of sea creatures. In 2021, Germany and China have seen astounding floods, wildfires of extreme magnitude have burned through Canada, California and Greece, and rain for the first time has fallen rather than snow at the summit of a rapidly melting Greenland. At the current rate, by 2050, 216 million people, mostly from developing countries, will be forced to flee the impacts of climate change. Radical action is needed and was needed long before today. (The Guardian, 2021)