Seven challenges for sustainable infrastructure

Delivering sustainable infrastructure is a big, and some would say, vague ambition. There is a lack of consensus on what this means in practice: ranging from merely specifying low-carbon concrete and (wrongly) thinking the job is done, to considering a much wider approach across a range of social and environmental themes. However, underlying the aspirations for achieving sustainable infrastructure are a series of very tangible and critical challenges that provide a sharper and more specific focus that will drive the changes needed. Seven of these challenges are summarized briefly below:

An important issue is to move from focusing on targeting carbon emissions to achieve net zero carbon by 2050, to working within a fixed carbon budget set for either specific infrastructure sectors (e.g. roads) or locations such as individual cities.

Current infrastructure projects are failing to meet this critical constraint. For example, it has been shown[1] that under current policy, housing alone would consume 104% of England’s cumulative carbon budget (2.6/2.5 Gt (under a 50% chance of <1.5^oC scenario). It has been estimated that all flights through an expanded Leeds Bradford airport by 2050 would take up almost double the entire carbon budget of the city of Leeds as a whole[2]. In 2020 Heathrow’s expansion was ruled unlawful for disregarding the Paris Climate Agreement which if it went ahead would mean aviation alone would account for nearly 30% of London’s carbon budget[3]. To stay within the 6^th carbon budget covering the period 2033-2037 (published in 2021) a 3rd runway, (adding another 7 MtCO₂ or more per year), would mean that – in order to meet legally binding targets – most other UK airports would be required to close[4].

These examples have very serious implications for infrastructure as it will be vital to deliver services within these carbon budgets rather than focussing on endpoint targets, as it is the pathway to zero carbon that matters more than a particular date when we hit zero emissions.

     2. Achieving net gain in biodiversity

Over 40% of UK species have fallen since 1970 and 133 species have been lost from the UK (mostly in the last 10 years). Estimates suggest that the conversion of agriculture and undeveloped land to urban development equates to an average 5.7% loss in species richness in the areas being developed. For housing expansion alone not to conflict with England’s 2030 wildlife abundance targets, Biodiversity Net Gain and species mitigation policies will have to fully compensate for these losses. At present less than 30% of species mitigation measures have been demonstrably successful at preventing harm to wildlife from new housing[5] .

The challenge is to incorporate greater use of green infrastructure and nature-based solutions in infrastructure projects. Yet the UK’s Natural Capital Committee has criticised the National Infrastructure Commission for failing to address the opportunities green infrastructure provides[6].

Globally 65% of total aggregates and 20% of metal materials are consumed in the construction sector and construction is responsible for the consumption of 60% of raw materials. Even supplies of materials as mundane as sand are beginning to cause concern. The most-extracted solid material in the world, sand is an unregulated material used extensively in nearly every construction project on Earth. And with 50 billion metric tons consumed annually, sand depletion is on the rise[7].

It’s just a matter of time before civil engineering organisations need to prepare themselves for a world where basic raw materials may be in short supply. This is a foreseeable constraint on future infrastructure activity – we really do only have one planet. Responding to this requires adopting principles of a circular economy which seeks to remove pollution and waste, whilst keeping materials in use for as long as possible.

The services provided by infrastructure are vitally important as long as they address real needs. These include reducing inequalities, providing fair and affordable access, and delivering multiple outcomes (beyond the primary purpose of the investment). Public sector projects already have an obligation to demonstrate how they are adding additional social value (under the 2012 Social Value Act). This requires active involvement with stakeholders where solutions are co-generated with those who will experience and use the services being provided.

     5. Responding to the Sustainable Development Goals (SDGs)

Infrastructure directly or indirectly affects all 17 Sustainable Development Goals (2015-2030) including over 70% of the related targets. For projects to contribute to delivering the SDGs economic, social and environmental sustainability must be integrated at the earliest stages of infrastructure planning in a way that considers the interlinkages between different systems and sectors throughout the entire infrastructure lifecycle[8]. Some have reported that the built environment sector has lagged behind other sectors in responding to these challenges[9], and new ICE President Keith Howells has highlighted more action is needed by civil engineers to help deliver the SDGs[10].

In many parts of the world infrastructure systems are reaching the end of their intended design life and in some cases exceeding it. This can lead to unsafe bridges; inadequate flood defences; decaying tunnels, pipelines, water treatment facilities and power supply systems operating beyond their intended capacity. Much is being done to address these aging assets and many opportunities exist in developing refurbishments and replacement to provide smarter, more efficient and lower carbon ways of delivering improved services. However, investment remains low.

     7. Speeding up change

As former ICE President Rachel Skinner has pointed out[11], time is against us and the changes necessary to address the above challenges need speeding up. This is perhaps the biggest challenge of all. That is to be accountable today and ask questions to identify what our contribution is, what is mine to do, and what is yours?

Reacting to these seven challenges requires questioning the easy option of just repeating what we did yesterday. Sustainable infrastructure is about the way we plan, design and construct and then operate and, importantly, use it.

_{[1] zu Ermgassen S., Drewnik M.P., Bull J.W., Corlet Walker C.M., Mancini M., Ryan-Collins J., Cabrera Serrenho A., ( 2022) A home for all within planetary boundaries: pathways for meeting England’s housing needs  Ecological Economics  201 (2022) 107562}

_{[2] Vogel J., Millward Hopkins J., Oswald Y (2019) We can’t expand airports after declaring a climate emergency – lets shift to low carbon transport instead. Tee Conversation 29 July.}

_{[3] Mayor of London Heathrow Expansion DCO Consultation Response Carbon and Climate Change}

_{[4] Airportwatch April 22 2021}

_{[5] Hunter S.B., zu Ermgassen., Downey H., Griffiths R.A., Howe C., (2021) Evidence shortfalls in the recommendations nb and guidance underpinning ecological mitigation for infrastructure developments Ecol. Solutions  Evid. 2 e12089}

_{[6] NCC (2019) State of natural capital Annual Report 2019 Sixth Report  to Economic Affairs  Committee of the Cabinet}

_{[7] Tim Newcomb (2022) Earth Is Running Out of Sand ... Which Is, You Know, Pretty Concerning}

_{[8] UNEP (2021)  International Good Practice Principles for Sustainable   Infrastructure  United Nations Environment Programme, Nairobi, Kenya}

_{[9] Baines-Buffery H. , 2018 Let’s Build a better future with the  Sustainable Development Gals  A Practical Guide for Construction Companies}  

_{[10] Claire Smith (2022) Sustainable Gaols Presidential Interview New Civil Engineer December 2022}

_{[11] Rachel Skinner (2022) Sustainable infrastructure for the 2020s: what might ‘really good’ really look like? Infrastructure Intelligence 7 June 2022}