The Carbon Project: the scale of the net zero 2050 challenge

Carbon emissions from infrastructure are decreasing, but engineers must think radically to help accelerate change.

Infrastructure enables lifestyle, and both will have to change. Image credit: Shutterstock
Infrastructure enables lifestyle, and both will have to change. Image credit: Shutterstock
A recent report to Parliament by the Climate Change Committee (CCC) on 24 June made headlines by revealing that the UK only has the policies in place to meet 20% of its legally mandated carbon emission reduction commitments by 2035, and betrayed a sense of frustrated urgency.


Last year, ICE commissioned research into how the industry has responded since the first Infrastructure Carbon Review in 2013. The results, presented in the Unwin Lecture 2020, confirmed that the proportion of carbon emissions deriving from infrastructure is still more than half (54%) of the UK’s total, and this proportion is likely to increase as the UK’s carbon footprint decreases. The footprint of other sectors is expected to reduce at a faster rate than that of infrastructure.

The research also showed that between 2010 and 2018 there was a 23% reduction in total carbon emissions relating to UK infrastructure’s construction, operation and use. Clearly, change is not only possible but happening. What, then, explains the sense of frustration accompanying the CCC’s latest report?

1. The overall rate of progress is still too slow

A 23% total reduction in emissions over eight years translates to an annual rate of 3%, a pace at which the UK will not meet its legal commitment to reach net zero by 2050. For that, an annual reduction rate exceeding 4% is now required, starting at once. In other words, as a minimum, we need to reduce the UK’s annual carbon emissions from infrastructure more than 30% faster than we are doing now.

Every year that we fail to accelerate change, we increase the problem – until a stringent yet achievable target becomes, eventually, unreachable. As the Infrastructure Carbon Review: Seven Years On report, published earlier this year, puts it: "Good progress but not fast enough".

2. Progress varies widely across different infrastructure sectors

Progress in reducing carbon emissions has varied widely between infrastructure sectors – communications, energy, transport, waste and water. The reductions in emissions from the waste and energy sectors (-33% and -37% respectively), for example, stand in contrast to an increase in emissions from transport in the same period (+3.9%).

Figure one
Fig 1: changes in sector emissions 2010-18 according to ICR update research, and shown in the Green Construction Board’s ICR 7 years on report.

It's true that each sector faces different challenges, including varying degrees of influence over the emissions relating to each stage of an asset’s lifecycle. It's notable, however, that in the two sectors with the most impressive carbon reductions to date – energy and waste – hugely ambitious policy packages were put together more than a decade ago to drive the changes we see today.

Similar ambition across all sectors would achieve the results we need in the years to come. Some aspects may require the development of new technologies or creative approaches such as systems of asset sharing or reuse – both of which will be explored later in The Carbon Project series.

Many, however, are simple to enact immediately, involving such mundane measures as better data management, less excavation or less waste. Consistent effort, driven by policy, may be more important than a stroke of genius, and would make a far greater difference.

Fig 2: Relative contribution to the UK’s infrastructure carbon footprint by sector (as of 2018)

3. New drivers are needed to accelerate the rate of change

In PAS 2080, the UK developed the world’s first standard for carbon management in infrastructure. Five years on, adherence to this guidance remains largely voluntary and uptake is patchy. While comparable countries are beginning to introduce compulsory whole-life carbon assessments and limit permissible emissions for construction projects, the UK’s progress in introducing policies to drive change is mixed at best.

There are encouraging developments, such as the new Construction Playbook (mentioned earlier in The Carbon Project blog series). Published in December last year, this stated for the first time that contracting authorities “should require that solutions put forward by potential suppliers are accompanied by a whole-life carbon assessment” and were obliged to “embed a whole-life carbon approach early in the identification and selection of solutions”.

The lack of such robust measures is exactly where the CCC’s current frustrations lie, but engineers can help.

Think whole-life, think radical

The greatest percentage reduction in infrastructure carbon emissions (44%) has been in those areas over which the industry has direct control: capital and operational carbon.

These areas, however, represent only 13% of the UK’s carbon footprint, with user-related emissions making up the other 41% of infrastructure’s 54% share of the whole. Put simply, 41% of the UK’s emissions derive from people using the infrastructure we provide. Infrastructure enables lifestyle, and both will have to change.

Fig 3: Carbon emissions associated with infrastructure, 2010 and 2017 (source: Green Construction Board/Dr. Jannik Giesekam)

Engineers are often reluctant to discuss the fact that the infrastructure we create inevitably shapes public behaviour, predicting or fearing public resistance and consistently underestimating the appetite for change. The recommendations of Climate Assembly UK suggest that a majority of people in the UK want protection and restoration of the natural world and are prepared to embrace quite radical change as long as it is delivered with consistent leadership, attention to fairness, sufficient explanation and involvement.

The tragedy of Covid-19 has brought a historic opportunity to embed changes in behaviour that will emphatically reduce carbon emissions in the future. What should we, as infrastructure providers, do to support this?

Direction of travel

Transport is currently the worst-performing sector in terms of carbon reduction. Remote working has proved to be both possible and popular to a far greater degree than was previously imagined. This has had an immediate impact on commuting and congestion and, if ongoing, guts the argument for road-building plans currently in place. Should we be reviewing England’s road building plans, much as the Welsh Government has recently committed to do?

If people work at home, local amenities grow busier, and often these can be reached quickly and easily using walking, cycling and public transport, some of which have been given greater support by local authorities during successive lockdowns.

Might this reduction in daily car journeys also create an opportunity to decrease the number of vehicles in private ownership – at least in towns and cities – through enhanced car-sharing schemes? Permanently reducing the number of private vehicles on the road would reduce carbon emissions to a greater extent than swapping the fuel source would ever do.

A permanent shift to homeworking has implications for other infrastructure sectors and for large areas of the economy – and these are the conversations that engineers should be contributing to. It is critical that we engage with policy-makers and contribute our expertise to the numerous forums in which such ideas are being explored.

Make your voice heard


Infrastructure that enables a lower-carbon lifestyle will come about when we challenge our own assumptions about what is needed and begin seriously to explore what is possible – taking our clients and users with us.

If you’ve saved carbon on your engineering project, you can apply to be an ICE Carbon Champion.

This blog is part of The Carbon Project series, exploring how engineers can contribute to achieving net zero in UK infrastructure. 

More information on the Unwin Lecture research.

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