Climate Adaptation with Urban Nature
Plus the three levels of climate adaptation
As we find ourselves at 1.2 degrees Celsius of global average warming, and rising, the effects of climate change are becoming obvious. Local weather is becoming more extreme and unpredictable. In 2022, heat waves and record breaking temperatures scorched Europe while one third of Pakistan was buried under floods. Over decades, the focus of climate action has been on mitigating climate change by reducing greenhouse gas emissions. However, as greenhouse gas emissions continue to rise globally, we are now forced to adapt to a new climate reality.
Climate adaptation involves changes to behaviour or infrastructure in response to climate change. You might think of flood defenses and storm shelters, but adaptation can be much more biophilic. Enhancing urban nature is a proven effective method of minimising heat waves and floods. Ecosystem-based adaptation is a way of working with nature to reduce the impact of severe weather while providing many other benefits to local people.
Cities by their design are especially vulnerable to extreme weather. Concrete, steel and glass absorb heat and release them slowly at night. In winter, this can be beneficial as it keeps temperatures at a more comfortable level and reduces heating bills (and emissions). In the summer, however, this ‘urban heat island effect’ can often raise temperatures in cities by 10 degrees Celsius higher than the surrounding countryside. This can turn a hot day into a dangerous situation for vulnerable people. Sadly, many elderly and sick people die during heat waves every summer, especially in cities, where escape from the heat can be almost impossible.
Cities are also particularly vulnerable to flooding. In natural areas, when rivers overflow or rainwater pours, water slowly sinks into the soil. However, cities are covered in impermeable surfaces like concrete and tarmac, which results in flooding when drainage infrastructure gets overwhelmed. This is happening more and more as climate change intensifies, with a resulting loss of life and property.
There is a clear solution to these problems: replacing urban human-made materials with soil and vegetation. Urban trees reduce temperatures by creating shade and adding moisture to the air (called evapotranspiration). A study of Baltimore City in Maryland, USA found that the city’s tree cover saves the lives of over 500 people annually by reducing heat stress. Restoring nature outside of cities can also help. In Southeast Asia, restoring coastal mangrove forests has been found to protect communities from storms and coastal erosion. And just think about all the other benefits these trees bring in terms of biophilia, biodiversity, food and recreation.
Life-Climate Interactions
A warming climate is a double edged sword for trees (and plants in general). A study published in 2017 found that urban trees have grown 14%-25% more quickly since 1960, possibly due to an increase in temperatures and carbon dioxide in the air. This is an example of a negative feedback loop; nature’s way of keeping balance. As carbon dioxide levels increase, photosynthesising plants simply absorb more and grow quicker to pull it out of the atmosphere.
However, since we are emitting carbon dioxide at a much faster than normal rate, and deforesting the planet simultaneously, this effect won’t be enough to mitigate dangerous climate change. In fact, we may be heading towards tipping points that cause mass declines in tree species as their habitable range shifts further towards the poles. If that happens, then cities could lose many shade-giving, flood-reducing trees just as we need them most. This is leading some scientists to call for the planting of tree species from warmer climates that are heat and drought-resistant; advice that flies in the face of ecologists’ mantra for prioritising native species for their biodiversity benefits. It's clear there will be no easy answers as we enter a new climate era.
Three Levels of Adaptation
The geographer Mark Pelling describes three kinds of climate adaptation; resilience, transition and transformation. This framing can help us to make sense of our adaptation options.
Resilience is the first level and can be defined as bouncing back to normal after experiencing shocks and stresses. For cities, resilience is about maintaining stability through a changing climate so life can go on as normal. Investing in ecosystem-based adaptation like urban tree planting can certainly contribute to this. However, we must also ask ourselves the question: if business-as-usual got us into this mess, why do we want to keep going as normal?
This is where level 2 of adaptation comes in: transition. Transition is about incremental change that guides us from our current state to something better. For urban nature that might mean an increase in urban agriculture and allotments or local residents taking the initiative to green their neghbourhoods. An example of this is the ‘greening permit’ in Paris. To deliver on their ambitious urban greening targets, the city of Paris offers a special permit to residents that gives them permission to take stewardship of a local green space to grow food, plant trees or otherwise improve its ecological richness. This successful idea could be easily replicated by cities worldwide as a way to transition towards a greener city while offering urbanites some much needed nature connection.
As the climate crisis intensifies, there are now growing calls for society to skip to the third level of adaptation: transformation. Transformation involves radical changes to our lifestyles, systems and values to create a truly sustainable way of life. Proponents of transformation argue that resilience will only lock us into the unsustainable status quo and transition is too slow to avert the worst of climate change.
Once we start thinking transformatively, we realise there are many more options open to us than we usually think. Transformation invites us to ask fundamental questions like: why do we need lawns? Couldn’t we turn our parks into biodiverse forests? What if we banned cars and rewilded streets? What if every neighbourhood had a local food growing cooperative that everyone contributed to and benefited from? What would happen if we designated our city as a national park? Could we capture rainwater locally and use it during periods of drought?
These ‘what if’ questions may sound fantastical. But real examples exist for all of them, which means they are possible. It’s just a matter of opening our minds, thinking bigger, and embracing the transformations that we know are necessary.