Being reactive to climate change is not enough. We must anticipate new challenges and design intelligently for a new era of extreme weather, writes Anna Beckett

Anna Beckett_columnist crop

Anna Beckett

As we read more and more stories about extreme weather events and watch as our governments do little to help to reduce emissions, it’s clear that we’re unlikely to manage to keep global temperatures within the critical 1.5°C. While it’s more important than ever to continue to try and reduce carbon through design wherever we can, it’s also important that we start to design for the world we’re going to live in.

With increasing heatwaves, flooding and high winds, are the structures we’re designing today going to be suitable in 50 or even 20 years’ time? And is there more we could or should be doing to make sure that they are?

Most buildings in the UK are designed for a structural design life of 50 years and, while currently many of our buildings are modified significantly or demolished within that time, lets assume we’re designing a building that will be used for the full 50 years. By 2072 we could reasonably expect to see significantly higher temperatures, higher pollution and extensive droughts during the summer months and higher wind speeds and flash flooding during the winter.

When it comes to drainage design, we have all been doing this for years. Drainage design is usually based on the 1 in 100 year storm data (i.e. the worst storm you’d expect to see, on average, once every 100 years), and includes a 40% allowance for climate change. And since the introduction of the SuDS Manual (Sustainable Drainage Systems) in 2007 the design of drainage almost always considers ways to store rainwater on the site so that local drainage systems aren’t overloaded.

We also need to become more efficient in the way we use water

Sustainable drainage design needs to start to go further, so that instead of just preventing flooding during the winter, we also become better at storing the water that we need to survive the summer. We also need to become more efficient in the way we use water by installing drainage systems that allow us to filter and reuse water within our homes.

For the structure itself the design codes do allow for climate change and there is an uplift in design loads for this, but it’s difficult to know if this is extreme enough and there are a whole host of other factors we’re not considering. We design for thermal expansion, but after a summer in which we saw 40°C in London, are the temperature ranges we’re considering high enough?

What about insects? Warmer, drier climates are likely to bring infestations of insects we’ve never previously dealt with in the UK and some of those could do a huge amount of damage to timber framed buildings.

Hotter and more humid climates, as well as increased levels of CO2 in the atmosphere, can also lead to increased corrosion in steel structures and accelerated carbonation of concrete - a process which eventually causes corrosion of the steel reinforcement inside the concrete. The corrosion protection that we apply to our structures needs to be modified to account for this and we need more regular maintenance of existing structures to ensure that issues are identified and dealt with quickly.

Unfortunately, our climate is going to change

But it’s also a little counter intuitive to “over design” for potential future situations, particularly when we’re trying to reduce embodied carbon. If the buildings we’re designing now are going to be habitable for the next 50 years we have to start to design for the situation we’re likely to end up with, rather than the ideal we’re hoping for. And maybe we can start to consider the impacts of these weather events differently - instead of fighting against nature maybe it’s time to start designing our structures to work with it or help manage those situations.

We know that taller buildings cause issues with wind and can lead to higher wind speeds. Couldn’t we design those buildings to intentionally channel the wind away from certain areas or use that effect to generate power? Or perhaps we could design homes that are truly demountable so that we can relocate them to avoid natural disasters?

Maybe we could utilise more innovative approaches to energy usage too. In Islington a community heat and power network uses excess heat from two local swimming pools as well as the underground train network to heat homes and schools. Schemes like this have the potential to reduce the waste heat we’re adding to the environment as well as reduce energy consumption.

Unfortunately, our climate is going to change, but preparing for that change gives us a real opportunity to consider a different way of designing. If we can learn to adapt the way we design perhaps we can create buildings that help us to deal with those changes.