Building a Low-Carbon Future: Definitions, Challenges and Policy (Dis)incentives

As part of IDEMA - DG Cities’ residential zero carbon research project - we have undertaken research to better understand the challenges and opportunities that arise from achieving zero carbon and energy plus buildings in the UK. In this first post of our new series, we examine the regulations in London and the nation at large that are shaping the future of the net-zero carbon residential sector.

Stay tuned for our next IDEMA blog, where we discuss insights from various experts in the building and energy sector about how to achieve zero carbon and energy plus buildings.


It has been over a month since the climate change activist group Extinction Rebellion took over the streets of London, amongst other cities, demanding that national governments take immediate action to address climate change. This sort of action is not unfamiliar to the country, however, as the UK Government has been under intense pressure to reduce its carbon emissions and to revisit its current carbon reduction target.

Following the UK Committee on Climate Change’s (CCC) advice, Teresa May recently committed the UK to achieve net-zero carbon greenhouse gas (GHG) emissions by 2050. While seemingly drastic, this commitment is necessary in order to help limit global temperature rise below 1.5 degrees Celsius above pre-industrial levels. The CCC have estimated that global society as a whole has just ten years to make the requisite changes and if we fail to do so, we risk facing potentially irreversible and catastrophic damage to civilisations and ecosystems alike. This net-zero carbon commitment is a major step in the right direction, but it is clear that much more remains to be done.

Back to basics

You might have heard of terms like zero carbon and net-zero carbon, which are oftentimes used interchangeably. However, these terms have distinct meanings that are important to differentiate. Below is a simple breakdown of the terms:

Zero Carbon: this means that zero emissions are emitted from the use of various objects, such as your home or car. Unless defined otherwise, this only refers to operational emissions (i.e. emissions from the activity itself, e.g. driving the car) rather than lifecycle emissions (i.e. emissions from manufacturing to use, e.g. production of the car and driving the car).

Net-Zero Carbon: this means that emissions are balanced by carbon removal (e.g. by planting trees).

The UK’s current commitment to meeting zero carbon

The UK Government's net-zero carbon commitment would require making drastic changes to the way that cities operate, especially in the transport and building sectors - the UK’s two largest carbon-emitting sectors. Ultimately, such necessary changes will largely be driven by making fundamental alterations to the country’s current policies.

Although the Prime Minister’s net-zero carbon commitment is yet to be reflected in the UK’s national regulations, cities such as London have set their own targets. The Mayor of London has pledged to make London a net-zero carbon city by 2050 and has identified intermittent targets: all new buildings are to have zero emissions from 2019, all bus fleets to have zero emissions by 2037 and all transport and buildings to have zero emissions by 2050.  

In addition to this, London has signed the World Green Building Council’s Net-Zero Carbon Declaration (NZCD), a commitment raised by C40 Cities. As part of this commitment, London, along with a number of other cities, has pledged to achieve net-zero operational emissions for new buildings by 2030 and for all buildings by 2050.

What are the legal drivers to achieving net-zero carbon?


The UK has taken a major step in the right direction by committing to be net-zero carbon by 2050. However, this is not enough. Regulations such as the national Building Regulations need to be updated. Part L1A (2013) of the Building Regulations outlines the energy efficiency and GHG emission reduction requirements for new residential developments. When applied, this results in a 6% reduction in emissions (compared to a 2010 baseline) - a negligible achievement when the goal is be ‘net-zero carbon.’

UK Building Regulations only account for emissions from heating and cooling, hot water, mechanical ventilation and internal lighting, which are termed ‘regulated emissions.’ This, however, excludes emissions from plug-in appliances (for example, your microwave). That means emissions from the energy used to power your TV and to charge your phone are not regulated and thus their reduction is not mandatory. As long as appliances are plugged in, and the electrical switch is switched on, kettles, TVs, phones and computers, for example, will consume energy, regardless of whether they are being actively used. So in reality, the UK’s net-zero carbon commitment does not actually mean that our buildings will be net-zero. Our buildings will continue to emit greenhouse gases, which will not be balanced by carbon removal.

In order for buildings to truly reach net-zero carbon, as defined by the Committee on Climate Change, the UK Government needs to take necessary measures to address or inform residents of the emissions generated from the use of their appliances, as such emissions are not being accounted for. The Government must also ensure that proposed developments provide estimates of such emissions as well as strategies to lower them.


London’s policies appear to contradict the national regulations. Policies in London go beyond the building regulation’s GHG reduction requirement and mandate that all new buildings aim to achieve net-zero operational carbon emissions (for regulated emissions). Policies in London likewise require that at a minimum, new developments must exceed the UK Building Regulation's GHG emissions reduction standard by 35%. While developments are encouraged to be zero carbon, they are not required to, and developers can simply pay a fee to offset the emissions not captured.

Should London continue to mandate a minimum 35% carbon dioxide reduction from new domestic buildings, then it will be very challenging for the city to meet its 2030 and 2050 net-zero carbon commitments. When the New London Plan emerges (the date of which is not yet confirmed), the same 35% carbon dioxide reduction will be applied, but it is expected that over time this target will gradually increase to mandate a 100% reduction in (operational) emissions. At present, London cannot legally enforce developers to target net- zero carbon - this must be applied by national government.

What does it all mean?

As it stands, UK regulations relating to GHG emission reductions are not rigorous nor stringent enough. They will not force the nation to meet net-zero carbon goals by 2050, regardless of individual city-led policies such as London’s, or the UK’s recent commitment to net-zero carbon. While we at DG Cities welcome the outgoing Prime Minister’s recent announcement, it is vital that the 2050 net-zero carbon target is enshrined in law and that the regulations, such as the national Building Regulations, are updated to reflect this. Without these changes and accompanying enforcement, the building sector will continue to act on ‘business as usual’ and remain as one of the UK’s leading contributors to climate change.