Nature-Based Solutions Blog
On this page is the first edition of the Nature-Based Solutions Blog.
Introduction
When I first arrived in Utrecht, I was stunned by how beautiful the city was. There were cute paved streets everywhere with intricate brick houses, tightly in a row, instead of the grass and concrete of my hometown.
However, that first summer, in an attic apartment on campus, I began to see a serious downside. Why were the houses so hot inside, when the temperature outside wasn’t even reaching 30 degrees? And why wouldn’t the house ever cool down properly?
What I was feeling was just a tiny taste of the true problem that our urban areas now face, and a problem which is projected to get much worse in the coming years. Dutch housing was built with a cooler climate in mind, but with climate change causing hotter summers, it’s increasingly difficult to keep our homes cool.
The urban heat island effect - the reason that urban areas are often hotter than the countryside - increases the stress on people’s health. This is a large contributor to why heatwaves are so deadly, (see this link and references therein). Multiple factors such as lack of sleep, and difficulty keeping well hydrated leads to the death of thousands every year.
The physics of the problem
So why are cities so hot?
A good deal of the answer lies in our building materials, and how these respond to the heat radiated from the sun. The warmth of the sun is absorbed by the objects it touches, to various degrees. When the sun goes down at night, the warmth that has been absorbed then radiates back into our surroundings.
Have you ever gone for an evening walk after a warm day, and felt the heat radiating off a brick wall? Compare this to how it feels to walk past a wooden fence. The building materials concrete, brick, and tile have an enormous capacity to absorb heat during the day, which influences how this heat is then re-radiated at night.
While this is an advantage on a cold day (any sunlight captured helps keep your brick house warm and reduces your energy bills), during the summer this effect is opposite to what we want. The more concrete an area has, the more intense the heat island effect. With our densely built cities, there is also reduced windflow available to remove this heat. (Reference: “Weather in the City“)
We could solve this problem by preventing the heat from being absorbed in the first place, but how can we do that without rebuilding an entire city?
Nature-based solutions
In a nutshell, Nature-based solutions are inspired by nature, cost-effective, and provide various environmental, social and economic benefits. They make our cities more resilient, and bring more nature into urban areas. (Full definition and EU background here)
In cities, the goal of Nature-based solutions is to make areas cooler and less prone to floods. Interventions such as green roofs or walls help reduce summer heat, while replacing paving with gardens, grass, or WADIs helps water absorb back into the ground, minimising flooding and relieving some of the pressure on the city sewerage systems
While these principles can be used when designing new parts of the city, the situation is more complex when we need to refurbish an already existing part. This complexity, and the balance between building new buildings and keeping the ones we already have, leads to some important questions.
What are the biggest problems in Utrecht, and what are the most effective ways of tackling these?
What interventions can we carry out in order to have the biggest impact, and how do we prove this?
And which practical steps should we take to improve the health of our most vulnerable residents?
These are the questions that I’m focused on solving, through implementing green interventions and collaborating with researchers.
Graphic showing global heating 1850-2024 , source here
Current collaborations - ongoing projects
There is a lot of amazing research going on into how to make our cities more resilient. From measuring the effects of Nature-based Solutions on both the environment and people’s health, to innovations into how to combine technology with green solutions.
One difficulty with there being so many initiatives is the lack of centralised data to assess ecological impacts of interventions. That’s why I’m very happy to be able to collaborate on the new project of Dr Katharina Hecht, who is leading the creation of a globally accessible, holistic, open science digital platform for this purpose. The goal is to connect building norms and strategies with their measured ecological and social benefits, supporting actors in designing regenerative architectural structures. More details can be found in the announcement here.
In addition to measuring ecological impacts, the effects on health outcomes for people who are in the vicinity of Nature-based solutions interventions is also of key importance, and this is why I’m also collaborating with Dr Anke Huss, an Associate Professor in environmental epidemiology. Anke’s work focuses on measuring exposures to various environmental factors and examining their impact on various health outcomes. Together, we will measure the health impacts associated with the cooling effect of a large green facade during the installation and growth phases. Also of particular interest are the perceptions of the residents, and social impacts that having more green in their neighbourhood may create.
I’m always very happy to discuss new ideas for research, so if you have a green idea that needs help with implementation, please reach out!
Nature-based solutions for private homes and streets.
Do you have interest in using Nature-based solutions in your own garden, or perhaps with neighbors on your street? There is growing evidence that the combined contributions from even small gardens can have a cumulative effect on neighbourhood air temperature measurements and the heat experienced by residents. A green facade, for example, can lower the indoor temperature by up to 3 degrees, while reducing the temperature of the wall itself by up to 30 degrees (“Weather in the City“ and references therein).
Do you have problems with excessive heat in your home? Are you curious what measures are suitable for your house, terrace, and/or garden? Please reach out for an obligation-free meeting!