England would use up the entirety of its 1.5C carbon budget on housing alone if the government sticks to its pledge to build 300,000 homes a year, according to a new study.
The building of new homes under a business as usual scenario, coupled with current trends on making existing homes more efficient, would mean the housing system would use up 104% of the country’s cumulative carbon budget by 2050.
Radically retrofitting existing houses, cutting the number of second homes, stopping people from buying houses as financial investments and making people live in smaller buildings would be more sustainable ways to address the housing crisis, the paper says.
A carbon budget is the cumulative amount of emissions a country can emit over a specific period. England’s 1.5C budget means restricting total emissions to 2.5 gigatonnes of CO2 between 2022 and 2050 say the researchers, who did not look at how this compares in Scotland, Wales or Northern Ireland, but they believe it is likely to be a similar picture.
“In the long run, we argue that England can’t go on building new houses forever, and needs to start thinking about better and more systematic solutions as to how we are going to house everyone within our environmental limits,” said lead researcher Dr Sophus zu Ermgassen, from the Durrell Institute of Conservation and Ecology at the University of Kent.
The paper, published in Ecological Economics, is the first to comprehensively analyse the impact of the government’s response to the housing crisis on national carbon and biodiversity goals. The researchers write: “Secure housing is a fundamental human right. However, potential conflicts between housing and sustainability objectives remain under-researched.”
They looked at two existing models, one for evaluating the emissions needed to run UK houses, and the other, emissions from constructing new housing. The figures come from looking at decarbonising trends of housing between 1990 and 2019, meaning housing is set to be 50% more efficient by 2050.
For England, if current trends continue, 92% of emissions will come from existing housing, and 12% from the emissions of building and running new houses, the study finds. There are about 25m dwellings in England, and the amount of emissions from existing homes is high because large parts of the housing stock are prewar, and more challenging to insulate. For example, half of homes built between 1919 and 1930 have uninsulated solid walls which account for almost half of heat loss.
Researchers looked at the biodiversity and climate impacts of these trends continuing as they are. “Our scenarios show how drastic the problem is and how ambitious the solutions actually have to be if we’re serious about staying within our 1.5C carbon budget,” said Ermgassen.
The paper also warns that policies to protect wildlife will have to be “very effective” if housing is not to undermine the government’s big biodiversity target of halting species declines by 2030.
The government has committed to implement legally binding targets to halve wildlife declines by 2030, which requires all new developments to have “biodiversity net gain”. Globally, 24% of threatened species on the IUCN red list are threatened by commercial and residential building developments.
Retrofitting existing stock so all homes could be zero carbon by 2050 would save 38% of the cumulative carbon budgets for 1.5C, the researchers say, adding that this is “by far the most impactful policy for reducing housing’s conflict with climate targets”.
Meeting housing needs without rapid expansion of housing stock is in theory possible, although the paper did not look at how many homes the government should be building. Using figures from the English Housing Survey, the researchers estimate that there are 1.2m empty or underused homes.
Dr Kate Simpson from Imperial College London, who was not involved in the study, said: “This is an ambitious paper that highlights some of the big problems with the current UK housing system, our collective lack of a cohesive strategy to meet carbon budgets, and fundamental biodiversity considerations. We urgently need more joined-up thinking like this.
“As my research is on housing retrofit, I agree we need to find incentives to bring empty homes back into use, protect the embodied carbon of existing homes and prioritise efforts to upgrade those to reduce energy demand while ensuring affordable housing and comfort for all.”