We’ve all heard the term net zero, but what exactly does it mean? Put simply, net zero refers to the balance between the amount of greenhouse gas produced and the amount removed from the atmosphere. We reach net zero when the amount we add is no more than the amount taken away. But how can we achieve this and why does it matter?
From countries and companies to individuals, tackling climate change is at the top of the agenda; and one way we can help to do this is to reach net zero. Indeed, the UK became the world’s first major economy to set a target of being net zero by 2050.
Evidence shows that our planet has been getting hotter. The warmest 20 years on record have been in the last 22 years according to the World Meteorological Organisation and the warmest four were all very recent: 2015 to 2018. Global average temperatures are now 1℃ higher than in the pre-industrial era.
A degree doesn’t sound like a lot, but the reality is that this incremental warming already appears to be having a negative impact. What’s more, if recent trends continue, this is set to worsen, with predictions of global temperatures increasing by as much as 3-5℃ by 2100.
Even with this tiny rise in global temperatures we are feeling the effects of climate change, with erratic weather patterns, including: heatwaves; floods and severe storms; loss of polar ice; and, rising sea levels. This will only get worse if global warming intensifies.
It’s widely recognised by scientists and governments that climate change is being triggered by higher levels of greenhouse gases in the atmosphere. Their name derives from the greenhouse effect they create by warming the Earth’s surface and the air above it. This is caused by gases that trap energy from the sun. The most common greenhouse gases are water vapour, carbon dioxide and methane.
Carbon dioxide is the most dangerous and abundant of the greenhouse gases, which is why cutting carbon emissions, carbon footprints or seeking low-carbon alternatives are suggested as ways to address climate change.
The excess of greenhouse gases in the atmosphere is triggering harmful global warming, so reducing the amount of these gases should help to tackle climate change. This can be done in two ways:
Net zero means achieving a balance between the greenhouse gases put into the atmosphere and those taken out.
Think about it like a bath – turn on the taps and you add more water, pull out the plug and water flows out. The amount of water in the bath depends on both the input from the taps and the output via the plughole. To keep the amount of water in the bath at the same level, you need to make sure that the input and output are balanced.
Reaching net zero applies the same principal, requiring us to balance the amount of greenhouse gases we emit with the amount we remove. When what we add is no more than what we take away we reach net zero. This state is also referred to as carbon neutral; although zero emissions and zero carbon are slightly different, as they usually mean that no emissions were produced in the first place.
Given the impact that carbon emissions have on our planet, you might wonder why we aren’t aiming for zero, or gross zero, rather than net zero. Gross zero would mean stopping all emissions, which isn’t realistically attainable across all sectors of our lives and industry. Even with best efforts to reduce them, there will still be some emissions.
Net zero looks at emissions overall, allowing for the removal of any unavoidable emissions, such as those from aviation or manufacturing. Removing greenhouse gases could be via nature, as trees take carbon dioxide from the atmosphere, or through new technology or changing industrial processes.
Net zero is important as it’s the best way we can tackle climate change by reducing global warming. What we do in the next decade to limit emissions will be critical to the future, which is why every country, sector, industry and each one of us must work together to find ways to cut the carbon we produce.