Net Zero: Frequently Asked Questions

The earth’s climate has already changed as the result of human-generated emissions. Global temperatures have been rising since the Industrial Revolution, thanks to the layer of greenhouse gas emissions in the atmosphere that allows in more of the sun’s heat than it allows to escape. The plant is now roughly 1°C warmer than in pre-industrial times.

The World Health Organisation estimates that between 2030 and 2050, climate change will cause roughly a quarter of a million additional deaths per year, but this may be an underestimate. A 2021 study involving dozens of scientists around the world found that the extreme temperatures (both hot and cold) caused by our changing climate are already causing over five million excess deaths every year.

We can’t remove the existing blanket of emissions, but we can stop making it too much thicker. The Intergovernmental Panel on Climate Change says that to avoid the most disastrous impacts of climate change, we should aim to keep global warming at below 1.5°C on pre-industrial levels. To do this, we need to reach net zero emissions by 2050.

The UK is committed to reaching net zero emissions by 2050. In the meantime, it is also committed to cut emissions by 78% (compared to 1990 levels) by 2035.

The UK has a legal obligation to reach net zero emissions by 2050. The target was made legally binding in 2019 through amendments to the Climate Change Act. However, it is not clear what the legal consequences (if any) of missing the target would be.

It is a very similar concept, but while “carbon neutral” means zero net carbon emissions, “net zero” means zero net emissions of all greenhouse gases.

Gross zero means zero absolute emissions; that is, no emissions at all. This is considered an unrealistic goal because some areas of the economy have emissions that are very hard and/or costly to avoid. Net zero doesn’t mean absolute zero; it would allow for some residual emissions to be generated as long as they were balanced by the equivalent greenhouse gas removal.

We need to get our consumption of fossil fuels as close to zero as possible. Independent expert body the Climate Change Committee (CCC) has set out detailed, science-based advice for how to do this. The key actions are:

• Reducing energy demand through changing our activities – e.g. walking instead of driving short distances, reducing meat consumption.
• Reducing energy demand through improved energy efficiency.
• A major expansion of renewable energy production.
• Electrifying our transport and heating so that instead of burning petrol or natural gas, we are using electricity that can come from renewable sources.
• Adapting industrial processes and freight transport to use hydrogen and investing in green sources of hydrogen.
• Investment in carbon capture and storage (CCS) and other technologies to reduce the emissions of heavy industry.
• Changes to farming practices and land use in order to sequester more carbon.

The CCC calculates that following their recommendations in full could cut the UK’s emissions by 95-96% on 1990 levels. Dealing with the remaining 4-5% will be difficult and may involve the use of technologies that aren’t yet developed, or require more drastic changes in our lifestyles.

Any greenhouse gases that are still being produced would need to be balanced through carbon removal projects such as reforestation or the restoration of wetlands.

Probably not. After passing the Climate Change Act in 2008, the government introduced a system of carbon budgets, specifying an emissions limit for each five-yearly period. Each budget is successively smaller than its predecessor, as we gradually reduce our energy use and transition away from fossil fuels.

The first (2008-2012) and second (2013-2017) carbon budgets have been met, and it looks likely that we will also meet the third budget (2018-2022). But there are two problems:

• We are currently not on track to meet the fourth, fifth or sixth carbon budgets.
• The original budgets were designed to meet our 2008 goal of reducing emissions by 80%, not our more ambitious target of net zero by 2050.

We actually succeeded in getting well below 1990 emissions levels in 2020, thanks to Covid and lockdown. But this drastic drop didn’t last, and we urgently need to cut emissions in a way that is more sustainable for the economy.

Making significant changes always incurs costs, but the changes required to meet net zero will mean savings in the energy costs required to keep the economy running.

The headline figure from the Climate Change Committee is a net cost of £321 billion, to be spent between 2020 and 2050. This is made up of an estimated £1,321 billion in investment, partially offset by £991 billion in cost savings. (The Office for Budget Responsibility backs up these calculations.)

The net costs won’t be the same every year during this 30-year period. It is likely that they will peak in 2027, when investment in power generation peaks and there is growing investment in buildings. From 2040 onwards, the savings from our climate strategy are projected to outweigh the costs, making it a net gain for the economy.

Of course, economy-wide calculations don’t convey the varying impacts on different sectors of the economy. Any plan for transition has to take into account the effect on sectors with hard-to-abate emissions. The UK government has already pledged that oil and gas workers “will not be left behind” on the road to net zero.

Like many people, the UK government is desperately hoping for a technological solution to enable “guilt-free flying” and is funding research into low-emission plane fuel. But at present, sustainable aviation fuel (SAF) is expensive and makes up just 1% of jet fuel. Electric planes are another avenue being explored, but they aren’t ready for widespread commercial use yet.

The current reality is that despite all these innovations, flying is still the most emissions-intensive form of transport mile for mile. If you travel by air, flying is very likely to be the biggest contributor to your personal carbon footprint, and it’s almost impossible to offset this with other lifestyle changes. Going vegetarian for a year might save half a tonne of carbon, while driving 2000 miles less per year would save about 0.8 tonnes. The carbon savings you make in a year with either of those big changes would be wiped out in a day by one flight from London to New York (nearly a whole tonne).

To put it in a global perspective, the average person living in Bolivia will only emit 0.47 tonnes in a whole year. There are many other countries where the average person’s annual emissions are below the level of a single long-haul flight.

The greenest option is to avoid flying wherever possible. Could that in-person meeting be replaced with a videocall? Could that short-haul flight be replaced with a train or ferry journey?

Yes, buying renewable energy helps to support generators and encourage investment in new renewable projects. But doing this isn’t quite as simple as choosing a “green” or “renewable” tariff from your supplier.

Generators of renewable electricity are given certificates known as REGOs by Ofgem, the energy regulator, to certify the greenness of the electricity produced. But it is currently perfectly legal for these certificates to be bought and sold separately from the energy itself. Many suppliers are taking advantage of this to buy all or most of their electricity from fossil fuel sources and then buy sufficient REGOs to label it as “100% renewable”. This means that although more than half of energy products sold in the UK are branded as “green”, very few actually involve directly supporting renewable generators.

The government is currently working on reforming this outdated system, but in the meantime businesses seeking to decarbonise their energy supply will have to do their homework. Ask your electricity supplier if they are recognised by Ofgem as providing additionality: that is, directly contributing to the construction of new renewable energy facilities. Tariffs that provide genuine additionality are granted an exemption to the tariff cap and there will be a letter from Ofgem to prove this.

Another option chosen by a growing number of UK businesses is to buy electricity directly from generators through a corporate power purchase agreement, or CPPA.

As for gas, the greenest option is biomethane, but the UK doesn’t make enough to meet even 1% of our gas needs, so it isn’t possible to decarbonise your supply. Opting for a gas tariff with a “green gas” element is helpful, but in the long term the best option is to move away from gas by electrifying gas-powered systems such as heating.

At the most conservative estimate, climate change is already killing hundreds of thousands of people every year, but the true number may be in the millions. As the world heats up, the number of people dying from climate-related causes such as heatstroke, flooding and malnutrition caused by failing crops will increase.

The Intergovernmental Panel on Climate Change has modelled various scenarios for how warming of 1.5°C and 2°C would affect the world. Limiting warming to 1.5°C would mean that around 420 million fewer people will regularly be exposed to extreme heatwaves. It will also significantly reduce the risk of drought and extreme weather events such as cyclones.

Unfortunately, even if we keep warming to 1.5°C, the changing climate is likely to endanger 6% of insects, 8% of plants and 4% of vertebrates. But allowing warming to hit 2°C would make the damage much greater: 18% of insects, 16% of plants and 8% of vertebrates would be endangered. The more species decimated, the greater the likelihood of problems with the food chain for humans.

The Climate Change Committee supports the electrification of heating systems across the UK in the coming years, but on the level of an individual business there isn’t a straightforward answer to this. The way the emissions stack up against each other depends on which types of heating system you’re comparing (gas boilers, heat pumps, electric panel heaters) as well as the type of heat emitter (underfloor heating, radiators, convectors etc.).

Probably the most important comparison to make is between an electric air source heat pump or a gas boiler; boilers only deliver about 0.9 units of heat for one unit of energy used, whereas heat pumps deliver about 3 units of heat for one unit of electricity used. Taking into account the associated carbon emissions factors, provided that the heat pump has a Seasonal Performance Factor of more than ~1.7 (and most do) then it is likely to have a lower carbon emissions impact than the boiler.

Of course, many businesses may have other motives for moving away from gas, such as price volatility and uncertainty of future supply.