Ross McLean, Graduate carbon management consultant
Around the world, people are experiencing the impacts of climate change through increased exposure to extreme weather, more frequent flooding and widespread damage to infrastructure.
With the need to reduce global GHG emissions to net zero by 2050 to keep the average global temperature increase to under 1.5°C, implementing low carbon solutions is vital to developing an appropriate decarbonisation trajectory. Natural interventions constitute a cost-effective and low-emission answer to combining climate change mitigation and adaptation. When opportunities exist to utilise the benefits created by natural environments, these should be implemented wherever possible.
Natural flood management (NFM) techniques, which aim to conserve, restore or emulate the natural functions of river catchments and floodplains to reduce flood risk, are one such example. Woodland creation schemes are highly effective since they intercept overland flow and encourage the infiltration and storage of water within the soil. Not only are they cheaper and quicker to implement than traditional structures, but they can also remove carbon emissions from the atmosphere through sequestration.
There is no doubt that in many situations, traditional engineered assets, such as concrete flood defences, are vital in protecting communities. Mott MacDonald have decades of expertise in designing such schemes and the demand for these measures is likely to rise in the coming years. In many cases, natural solutions such as NFM will not replace traditional assets, but can be used in conjunction with them to reduce flood risks overall.
Opting for natural protection techniques minimises our reliance on complex, expensive and carbon-intensive structures such as concrete flood defences that fulfil the same purpose. This means they can be used where previously there was no economic case or funding available to develop other flood management measures. As climate change disproportionately affects poor communities, natural solutions could also play a role in reducing inequality around the world.
By mitigating the magnitude of a flood event using natural means, the requirement to use carbon-intensive materials such as concrete and steel can be significantly reduced. For asset owners, these design changes will likely result in significant cost savings.
Filling in the gaps
To increase the uptake of natural solutions, more research is required. Firstly, we need to better understand how effective they really are, as well as accurately quantify their associated carbon savings, which will increase their credibility. At present, quantifying carbon sequestration is challenging, so is calculating the emissions avoided by minimising the use of carbon-intensive materials.
Reduction targets and the use of carbon calculator tools are all well-established practices within the infrastructure sector. Mott MacDonald have helped drive this through the development and implementation of PAS 2080, the world’s first standard for managing carbon in infrastructure, and by creating bespoke carbon calculator tools for a range of clients.
To be a viable alternative, these assessments should also apply to natural solutions. To facilitate this, Mott MacDonald have been working with the UK government’s Environment Agency to deliver an approach for calculating the carbon associated with NFM schemes. Robust carbon calculation methodologies will help to create a business case and unlock funding streams by showing the carbon savings achievable within a project.
By better embracing natural solutions and rigorously demonstrating their benefits, designers and asset owners can save costs and radically reduce carbon emissions across the infrastructure sector.