What does ‘net zero’ mean, and why is it so important?

23 June 2021 | Aimee Tweedale

If you’ve been paying attention to the news lately, you’ll have heard the term “net zero” cropping up more often. Reaching net zero is a huge goal on our path to fighting the worst effects of climate change

But what does it actually mean?

A couple hiking in nature

Here, we’ll take you through the definition of net zero, the UK’s net zero target, and what needs to happen to make sure we get there. 

What does net zero mean?

Net zero is all about balance. 

Specifically, it’s about balancing the level of greenhouse gases in our atmosphere, so we’re not putting in more than we take out. 

The first step to net zero is reducing greenhouse gas emissions as much as physically possible, in line with what scientists recommend. The second step is to remove the remaining emissions from the atmosphere. This is usually done by restoring and protecting nature, like trees and peatlands, which naturally absorb carbon from the air. 

In theory, this takes the level of greenhouse gases being pumped into the atmosphere to zero – hence, net zero!

Confused? We know it can be a head-scratcher! Picture it like this: imagine all the world’s people are sitting around a giant bathtub, each filling it up with their own hosepipe. The water coming out of the hosepipes represents the greenhouse gases we’re releasing into the earth’s atmosphere (or the bathtub). 

We can’t let the bathtub overflow. So we have to stop putting so much water into it, and use buckets to scoop out the excess. This is the basic idea behind net zero: we can’t emit more gases than we remove. 

What are greenhouse gases? 

They’re the gases that are causing climate change. They include naturally-occurring gases like carbon dioxide and methane. 

While these are fine in small amounts, right now, there’s way too much of them in our atmosphere, and it’s heating up the earth. This has happened as a result of burning fossil fuels and other human activities.

Find out more about all this in our complete guide to climate change.

To slow down the effects of climate change, we need to stop releasing more greenhouse gases into the air. When we reach net zero emissions, that will mean we’re not emitting more greenhouse gases than we’re taking out of the atmosphere. 

Remember: “net zero” is still a new term

Something important to bear in mind about the definition of net zero is that it’s still evolving. It’s a pretty new concept. 

This means that each country, company, or organisation that’s announced a net zero target could have their own slightly different definition of what that means. 

An organisation called the Science Based Targets Initiative is currently in the process of creating a definitive set of guidelines for corporations setting net zero targets

Why is reaching net zero important?

So now you understand what net zero is all about. But why does it matter?

As we explained a little bit earlier, greenhouse gas emissions are what’s causing our planet to heat up. These gases include methane, water vapour, ozone, and the big one: carbon dioxide. (This is often referred to as just “carbon”.)

Having a certain amount of these gases in our atmosphere is a good thing. They make it possible for us to live on earth! But since humans started burning fossil fuels, the amount of greenhouse gases being released has rocketed, upsetting the earth’s natural balance. 

Since the Industrial Revolution in the late 18th century, our planet has warmed by about 1C.

In 2018, the Intergovernmental Panel on Climate Change warned that we need to stop that number from going over 1.5C. If we don’t change our emissions at all, we’re on course to pass the 1.5C mark between 2030 and 2052.

Let’s say we don’t do anything right now, and our earth heats up by 2C. Compared to the 1.5C scenario, we’ll be facing:

  • 10cm higher sea levels
  • Worse heatwaves, droughts, and flooding all over the world
  • 10 times more chance of an ice-free Arctic in summer
  • More mosquitoes carrying deadly diseases
  • Difficulty growing crops for food worldwide

These are just a few of the potential effects of climate change.

To stop the earth from heating up by more than 1.5C, we need to reduce emissions globally by 45% by 2030. Then, we need to reach net zero emissions by 20501

Greenhouse gas emissions

2050: the UK’s net zero goal

In 2019, the UK government officially committed to reaching net zero emissions by 20502.

As a country, we’ve already brought emissions down to half what they were in the 1990s. This has mainly been achieved by ditching coal from our energy system, and making big changes in the manufacturing and waste industries3.

2020 saw the biggest drop in emissions so far, at about 8.9%4. But that was largely due to changes caused by the coronavirus pandemic. To make sure we hit the target, we’re going to need to make more long-term changes to our society and our economy.

What are the UK’s greenhouse gas emissions?

In 2020, the UK released an estimated 414.1 million tonnes of greenhouse gases into the atmosphere5

Right now, the government works out this figure by looking at greenhouse gases that are produced geographically within the borders of the UK.

This means that the official statistics don’t include emissions that the UK causes abroad, or through international aviation and shipping. 

But climate advisers have pushed for this to change, to give a fuller picture of the UK’s emissions. The government has now agreed to include international flights and shipping in the sixth Carbon Budget. This is the plan to limit emissions from 2033 to 2037, in order to slash emissions by 78% before 20356.

Is the UK’s net zero goal possible?

Getting to net zero by 2050 is possible. Scientists and other experts have determined 5 different ways for the UK to get there. But it’s not going to be easy: it will mean a total overhaul of several areas of life in the UK today. 

These kinds of large-scale changes have been made before – for example, when the whole country switched to digital broadcasting in 2007-2012.

But reaching net zero will be the challenge of a lifetime. In their latest guidance for the government, the Climate Change Committee wrote that to meet the UK’s net zero target, we will need to:

  • Do more than just reduce emissions. Where there are zero-carbon options, we should be using those, rather than just lowering our greenhouse gas emissions. 
  • Get everyone involved. Reaching net zero will need everyone in the UK to make changes to their lifestyle, whether it’s the car you drive or the food you eat.
  • Make it a priority. Scientists say getting to net zero should be at the centre of our economic recovery from the Covid-19 pandemic7

How can we reach net zero?

There are several potential pathways to net zero. Some of these scenarios involve the use of carbon-capturing technology that hasn’t actually been invented yet. 

The Centre for Alternative Technology recently produced a report detailing how we can get to net zero using technology that already exists. Their report says that primarily, we need to:

  • Reduce our demand for energy: with more efficient buildings and transport, we could cut the amount of energy we use by as much as 60%
  • Power up renewable energy: making sure that all our energy demand is being met by renewable sources like wind and solar, rather than fossil fuels
  • Change our diets, and how we use our land: restoring the biodiversity of our land, and shifting away from animal agriculture

Here’s a bit more detail on some of the key actions the UK needs to take to reach its net zero goal. 

Woman shopping for fruit and vegetables

The energy transition

The energy transition is the shift we described above, away from fossil fuels, and towards renewable energy.

It’s going to be a huge job, but the good news is that it’s already underway. In 2020, more of the UK’s electricity was generated by renewables than by fossil fuels for the first time ever8.

Find out more about what renewable energy is, and where it comes from.

The next step is to make electricity the core of our energy system, rather than gas. Which brings us to our next point...

Decarbonising heat

This is a big one. In the UK, the energy we use to heat buildings (and supply them with hot water) accounts for a whopping 15% of our greenhouse gas emissions9.

By 2050, we need to have moved away from heating our homes with gas, using electricity to power our heating instead. It’s a tall order: right now, 90% of British homes are heated by gas boilers.

That’s why the government has announced that gas boilers can’t be installed in newly-built homes from 2025, and will not be sold at all from the mid-2030s10.

What will replace your boiler? Find out more about low carbon heating solutions. 

Electric cars

Buildings won’t be the only thing getting the electrical treatment. To get to net zero, we also need to ditch petrol and diesel-fuelled cars, and make the switch to EVs.

In order to cut emissions from our roads, the government has announced that no new petrol or diesel cars will be sold after 203011.

If you’re thinking of investing in an electric car, read our complete beginner’s guide, from our resident EV expert Chris Britton. 

Changes to our behaviour

All the steps mentioned above will have an impact on all of us. But they’re also large-scale, top-down changes. What can we do as individuals?

The truth is that we will only reach net zero if each of us enthusiastically does our part. According to a report from the International Energy Agency, about 4% of the emissions reductions we need to reach our global net zero target will come from individual people changing their behaviour12.

That means things like cycling or walking instead of driving, choosing not to take a long-haul flight, and changing your diet towards more sustainable, locally-grown food. 

If you want to map your own path to net zero, start by reading our guide to 30 ways you can live a greener lifestyle

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What other countries have set a net zero carbon goal?

This handy tool from the Energy & Climate Intelligence Unit shows where all countries are in their journey to net zero emissions.

The UK, Sweden, France, Denmark, New Zealand, and Hungary have all made their net zero targets law. The US and China, the world’s biggest polluters13, are both currently drawing up their net zero policies. 

Bhutan, the small, predominantly Buddhist nation in the Himalayas, is the world’s only carbon-negative country. It achieved this feat by protecting its 70% tree cover, generating hydroelectric power from its rivers, limiting tourism, and giving free electricity to farmers14.

OVO’s net zero emissions mission

As an energy supplier, we know we have a big role to play in the UK’s journey to net zero. In 2019, we launched Plan Zero, our own commitment to reach net zero by 2035. 

Our plan is underpinned by a science-based target. It’s aimed at keeping global warming to less than 1.5C. 

We’re doing this by:

Read more about everything we’re doing to reach our net zero goal.

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