Cities are big carbon emitters, but their density means they can also play a big part in reaching net zero.
Over 300 local authorities have now declared climate emergencies. But what role do they have in helping the UK achieve its net zero target? Our latest report sets this out.
Climate change is a global issue, which will mainly be led by national governments. Because of this, much action to meet net-zero (such as changes in electricity generation) will happen to cities rather than being driven by them. But there are two areas where place does matter – transport and domestic emissions. Despite the large strides the UK has made in cutting carbon emissions in recent years (mainly through switching away from coal and carbon-intensive industry) emissions from these two areas have remained stubbornly high.
On these two counts, cities and large towns are likely to play a key, disproportionate role in helping the UK hit its net-zero target. This is because their higher densities are better able to support public transport networks and lower carbon homes.
Let’s look at transport first. The large majority of emissions from this sector comes from road transport. Private cars are the largest emitter: in 2018, they were responsible for about 60 per cent of all transport emissions. Electric vehicles will help this shift, but public transport and active travel will need to increase too, and this will happen more easily in cities. In dense urban environments, journeys tend to be shorter, so they can more easily be walked or cycled. Public transport is more sustainable too – this helps explain why London’s transport ridership is so high and transport emissions per capita are relatively low compared to many cities (London ranks 12th in the cities with the lowest transport carbon footprint).
Second, housing. Domestic emissions are influenced by a number of factors, including the type of fuel used, the age, size, quality and condition of the dwelling. A large part of the challenge will be to cut emissions from the current housing stock, by improving its energy-efficiency- one of the worst in Europe. And of the total 11.2 million homes that need retrofitting, 56 per cent are located in cities. The other important part of the challenge will be to limit the emissions of our future homes, and this will mean carefully choosing the type of homes that are being built. Density is again important here: compact housing, like flats or terraced housing, emits much less carbon annually than typical out-of-town single-family detached housing: about four tonnes per dwelling for the former, against more than eight in the latter.
The size of the prize associated to changes in modal shifts and upgrades of the housing stock is quite substantial: our calculations suggest it could be up to 87 per cent reduction in transport emissions, and up to 40 per cent reduction in domestic emissions by 2035.
For all those places that have declared climate emergencies, planning policy is the main tool they should be using, rather than a more traditional approaches such as encouraging more people to get on a bus. The latter will only work if we change the way we plan, build and manage our cities, by building more compact, energy-efficient housing on existing built-up areas, and near existing public transport stops. And it should be backed up by other policies that local authorities have but most have been reluctant to use, such as the introduction of Clean Air Zones.
It will also need national government support. Better coordination of housing and transport planning will require national government to devolve more powers at the local level, so that they sit within a single authority- like they currently do in London. Meanwhile national government action will be needed on issues such as the phasing out of petrol cars and the reintroduction of an improved housing retrofitting programme.
Cities have a reputation for being bad for the environment. When talking about climate change, the opposite is true. But if they are serious about climate change then city authorities need to change their approach to how they plan and build their neighbourhoods – much else will just be hot air.
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