Net zero and resilience: infrastructure’s joint climate challenge 

Tough decisions are being taken across the sector to limit the climate impact of infrastructure’s construction, operation and use


From the destructive power of storms and floods to the threats posed by heatwaves and droughts, the world is having to come to terms with more and more extreme weather events caused by climate change.

For decades the global reaction has been slow, the science ignored and the evidence side-lined as an inconvenient truth. But now the need to change is front and centre, from cutting and mitigating the emissions we already produce, to adapting and increasing our resilience to unpredictable weather.

Central to cutting carbon is the goal of net zero, until recently a vague and nebulous target, which looked good on marketing material but few really understood what it meant and entailed. This changed, says Rachel Skinner, an executive director at leading engineering professional services consultancy WSP, when the Science Based Targets Initiative (SBTi) issued its own standard. “For the first time organisations across the world were all able to say exactly what we meant by net zero,” she says.

The standard sets out how companies can align their near- and long-term climate action with limiting global warming to 1.5°C, she continues. “It makes clear that the first job is to reduce your emissions as far as you can, before using offsetting as a last resort.”

But while there’s optimism, there is also realism. Last month in its annual progress report to parliament, the UK’s Climate Change Committee (CCC) was highly critical of the government’s efforts to enact policies that would get the UK to net zero by 2050. CCC chair John Gummer, Baron Deben, said: “Holes must be plugged in its strategy urgently. The window to deliver real progress is short. We are eagle-eyed for the promised action.”

There was particular criticism for the government’s policies around insulation and the failure to enact promised plans to address the fact that UK homes are among the draughtiest and least energy-efficient in Europe.

“A huge level of change is needed over the next decade if we stand any chance of getting to net zero by 2050,” adds Skinner, whose own organisation has committed to halving the carbon impacts of its designs and advice by 2030.

The need to keep building

But while a net-zero planet by 2050 is the goal, new infrastructure projects will continue to be developed. Some three quarters of the global infrastructure that’s needed by 2050 is still to be built, yet the construction industry accounts for 38% of global CO2 emissions.

But mothballing the construction sector is not an option. The world needs flood defences and new hubs for the likes of wind and hydrogen energy, while a key argument to come out of COP26 in Glasgow was that the push for sustainability needs to be equitable.

People in developing countries need a roof over their heads, clean water and sewage systems too, says Dr Andrew Minson, concrete and sustainable construction director at the Global Cement and Concrete Association (GCCA). “To get to net zero it’s not enough to say we have to do without, and leave these developing countries stranded.”

The cement industry is one the most energy-intensive and hardest to abate, concedes Minson, but it does have a roadmap to achieve net zero by 2050. This is largely based around using waste materials to replace the cement needed to make new low carbon concrete. Recently, a sector-wide initiative called ConcreteZero launched to help the industry reach net zero, with WSP being one of 17 founding members.

Society needs to be a lot more honest with itself. We need to get past all these paper-thin promises and claims that can’t be born out in reality but which make us all feel good, and get on with creating real change

Designers, Minson says, can use tools like the GCCA’s roadmap “in very creative ways and deliver projects that are sustainable,” such as concrete paving that is porous to help reduce flooding. Overall, he adds, the roadmap shows the sector’s potential to reduce carbon across the built environment by 40% by 2030, saving five billion tonnes of carbon in the process.

“We’re not waiting for a eureka moment,” says Minson. “It’s not a technology barrier, it’s actually a policy barrier.” Governments are responsible for around 60% of procurement for infrastructure projects, he says, but they’re not specifying break-through technologies such as low carbon concrete. “And that’s actually not for any technical reason at all, it’s actually because of habit.”

Infrastructure’s dual role

According to James Heath, chief executive of the UK’s National Infrastructure Commission (NIC), infrastructure has a role to play at two levels. “Firstly, projects can help boost society’s protection against and adaptation to climate change, taking the form of things like sustainable flood resilience measures. Secondly, infrastructure assets themselves need to be more resilient to the risks in how they are designed and operated.”

The commission’s design principles for national infrastructure have been adopted by government for all major projects, he says. “They place climate as the very first principle; not only should projects be built and operated in a way that reduce emissions, but its design should enable the people and businesses using it to reduce their wider climate impacts too.” For instance, he adds, the blueprint for Tideway, a new 25km super sewer under the Thames, include active travel spaces and parks, as well as the tunnel itself.

Railways are one of the sectors that need to adapt to climate change now, while also looking at how to make itself more resilient in the future. In the UK, Network Rail has recently produced its third adaption report which, says group safety & engineering director Martin Frobisher, shows “how the railway responds when the climate bites back (and) also how we minimise our emissions in order that we do less harm.”

Earthworks pose one of the biggest headaches, he says. Largely built in Victorian times, and to no set design code, they are much steeper than they need to be, making them particularly susceptible to landslips caused by heavy rain.

Rebuilding thousands of miles of railway embankments is unfeasible, he continues, so instead Network Rail: “is focussing on modern telemetry, instrumentation and better weather forecasting so that we can safely manage the railways during extreme weather.”

Better drainage is also set to play a crucial role, with big, open channels, which can convey huge volumes of water, replacing restrictive underground pipes which often can’t cope with the type of deluge we’re now experiencing as a result of climate change. The channels are a cost-effective solution too and are made by using simple fabric blankets impregnated with concrete rather than expensive shuttering, says Frobisher. These are laid in channels and then sprayed with water and left to set.

The track itself is most susceptible to heat, but learning lessons from countries such as Saudi Arabia, all new track in the UK is now stretched and installed under tension. When it does heat up, the tension relaxes, preventing the track from buckling.

Mitigation is also a part of future-proofing the rail network, adds Frobisher, and decarbonising the network is a priority too, with electric replacing diesel and solar panels now standard on most new stations.

Unity within the industry and creative solutions to mitigating climate costs can help the infrastructure sector achieve both its net zero and resilience aims.

“Society needs to be a lot more honest with itself,” says Skinner. “We need to get past all these paper-thin promises and claims that can’t be born out in reality but which make us all feel good, and get on with creating real change.”

The impetus to change is real. It now relies on collaboration by all levels of government, businesses and communities to make that change a reality.


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