January 30, 2025 - 10:00am

According to the latest official projections, the number of people in Britain will rise by 4.9 million in the space of a decade. From a base level of 67.6 million in 2022, the Office for National Statistics (ONS) forecasts a UK population of 72.5 million by 2032.

The ONS puts the number of births in this 10-year period at 6.8 million. However, that’s cancelled out completely by 6.8 million deaths. In other words, the whole of the 4.9 million population increase is accounted for by immigration.

Think about what that means in terms of housing, transport, jobs and consumption. Typically, the immigration debate centres on the economic, social and political ramifications, but what about the environmental impact?

Through its Net Zero target, Britain is committed to reducing its CO2 emissions from 300 million tonnes a year to the best part of nothing by 2050. Moving millions of people from low-carbon economies to a higher-carbon economy obviously runs counter to that objective.

Consider the additional demand for housing. The average number of occupants per UK dwelling is 2.2 — on that basis, an extra 4.9 million people means over two million extra homes will be needed. The Government has plans to drastically reduce the emissions from domestic heating and hot water, but that won’t help with the issue of embodied carbon — i.e. the amount of CO2 emitted in the process of constructing and providing the materials for each new home.

Studies show that two-thirds of all the lifetime emissions from our homes come in the form of this upfront cost, with estimates in the range of 0.4 to 0.85 tonnes of CO2 per square metre. Assuming an average dwelling size of 100 square metres, the embodied cost of two million extra homes comes to between 80 and 170 million tonnes of CO2. Sadly, few environmentalists will address these unwelcome facts.

And it’s not just about emissions: there’s the land taken too. Just how much countryside we’ll need to sacrifice depends on multiple factors such as housing density and use of brownfield land, but think about the overall impact this way: 4.9 million is very nearly the population of Scotland. If it takes all of Edinburgh, Glasgow, Aberdeen, Dundee and hundreds of smaller communities to accommodate that number of people, then that gives us an idea of the scale of development needed across the UK to house just 10 years of immigration-fuelled population growth.

So what does the green Left have to say on this issue? Not a lot. George Monbiot’s weekend column in The Guardian is a prime example. He lays into Labour’s “build baby, build” housing policy, but doesn’t mention immigration once.

Of course, progressives can still make the case for a liberal immigration policy on humanitarian grounds. But that doesn’t change the fact that making room for five million extra people will mean a lot less space for nature.


Peter Franklin is Associate Editor of UnHerd. He was previously a policy advisor and speechwriter on environmental and social issues.

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