The landscape architect and climate change

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Climate change is a threat to people and the ecosystems that landscape architects serve and depend on. Landscape architecture and urban design are disciplines that are uniquely poised to handle the implications of climate change. While architecture has the capability to help mitigate climate change through improvements in energy efficiency and construction materials, landscape architecture & urban design has the capacity to not only mitigate, but to adapt to climate change.

London’s Senior Associate Director Angus Palmer talks about how climate change is now integral to the role of landscape architecture and urban design; and the means that these professions have to help address the climate crisis.

Carbon dioxide and global warming

To address the climate change problem we must first understand it. The relentless rise of carbon dioxide is having an extreme impact on the atmosphere and global warming. Carbon dioxide concentrations are driving what appears to be runaway climate around the world. The unbalancing of the weather threatens the sustainability of the planet’s ecosystems, as well as the future of humanity and the stability of the global economy.

Today, we stand on the verge of a new geologic era; the "Anthropocene", one where the climate is very different to the one older generations knew.

Each year we are hearing of more extreme weather events. The correlating data which supports this is the average global temperatures and carbon dioxide particles per million (ppm) in the atmosphere. (Refer to figure 1).

To summarise this data; 350ppm is considered a satisfactory level. We reached this level in the 1980’s. In 2013 we reached the point of no return when the levels reached 400ppm. Today’s reading is at 418ppm and rising. 430ppm would push the world past its target for avoiding dangerous climate change.

According to an ongoing temperature analysis led by scientists at NASA, the average global temperature on Earth has increased by at least 1.1° Celsius. Most of this has happened in the last four decades, the same time when carbon dioxide ppm has significantly increased in the atmosphere.

There has been several global agreements to address these alarming changes. The most recent being the Paris Agreement. It’s aim is to limit global warming and keep the average global temperature below 2°Celcius, with an aim to limit it to 1.5°Celcius. The Agreement also aims to bolster countries' capability to deal with the impacts of climate change and support them in their attempt to reverse the impacts of the climate crisis. When it comes to the built environment, this intent is very aligned with the landscape architects’ professional capabilities. How can we offer our services and what should we be mindful of in our work?

The emergence of the landscape architect in the climate crisis

Globally, landscape architects are now asking how we can build capacity, rather than just export commercial services. To do this it requires a broader understanding as the built environment has more complex issues to deal with than it did years ago. Examples of where landscape architects have shown versatility and innovation include the emergence of nature based strategies for coastal edges and resilience in the consequence of super storm events. These types of interventions have opened more doors for landscape architects to provide socio-political and ecological processes, rather than just providing placemaking services.

In the 21st century the landscape architecture project is one of social justice, ecological synthesis and global reach. It is now a profession that is as much analytical, scientific and technical as it is a form of art and organisation. Gone are the days of seeing landscape architects just as park or garden designers. They are seen as problem solvers, people that see the built environment holistically and who look at their work very conscious of doing what they can within the project they are working on; to help reverse climate change. They are inclusive collaborators and leaders of the built environment who are always looking to bring more people to the table.

Through the process of designing for climate change adaptation or mitigation, it’s imperative that local communities are also bought into the discussion. Local people have an attachment to place and must be at the table as a participant.

Merging science and design

To create interventions that mitigate and adapt to climate change, the best outcome is typically a collaborative process of merging science with design. This needs to be accompanied by effective policy and more research.

When it comes to redeveloping or upgrading grey infrastructure, building back what was there is always a default perspective. Old habits and old technologies always equal predictable outcomes. Innovation needs to be at the forefront of the process and sometimes innovation has to break the rules. Innovative change isn’t going to be resolved just by an engineer’s design or an architects pencil alone. It needs to be done by a fully multi-disciplinary and collaborative process, while design teams need to also understand the region and the interdependencies and systems of the project location.

The role of the landscape architect in fighting or helping reverse climate change

Climate change is mainly caused by human activities. How can landscape architects and urban designers reshape spaces and systems to enable changes in human behaviours that will in turn reduce the carbon footprint of the individuals who exist in a city, live in a neighbourhood or visit a space? It can be more than just planting, installing new green infrastructure and thinking about materiality and its upstream and downstream impact.

What we need is big scale ideas to tackle climate change and ensure different places have different approaches.

This can be a two prong approach - mitigation and adaptation;

Mitigation

To help mitigate climate change landscape architects have a number of strategies to call on. Mitigation, is slowing down global warming by reducing the concentration of GHG’s within the atmosphere. It is something that as designers we can implement at varying scales and enable by introducing and encouraging new behaviours through efficient design.

Planting is obviously the most well known landscape architectural means for mitigating climate change. Plants are powerful tools to sequester carbon. The type of plants selected for a certain environment, the way they are positioned, and how they are maintained are vital components in determining the actual carbon sequestration potential of different landscapes. When we also plant, thinking about pollinator friendly vegetation is also important. It preserves the very ecosystems and species we are trying to protect.

Appropriate and proper soil management is another effective form of mitigation. Soil is a powerful tool which if healthy can capture and hold carbon, which means it must be looked after and managed if it is to realise its sequestration potential. Soil rehabilitation in large natural spaces and of course in agricultural land can remove carbon from the atmosphere and of course generate resilience to drought. Healthy soils in agriculture also equates to healthier food. Currently the practical implementation of soil carbon strategies at a large scale lags behind its potential.

Transport is a major contributor to both air pollution and carbon emissions; often being responsible for over a third of a city’s carbon emissions. When thinking of large scale ideas and projects, landscape architects and urban designers have capacity to work collaboratively with local authorities, clients and transport planners to realise a well integrated sustainable transport system, which also includes effective micro-mobility networks and of course improved walkability. A new large scale movement system also preserves city centres and opens up new urban neighbourhoods, often removing non-essential motorised traffic to create more accessible, future proofed and liveable places. Getting people out of private vehicles and into other modes of transport is integral to cities achieving their net zero goals.

When a transport journey works well, it becomes a positive experience within a city and helps a city or neighbourhood become economically productive. The cyclist and pedestrian are often the biggest players here. Their journey experience is crucial to leaving people with a positive experience of a city. How often do you hear people returning from a city with good walkability and bicycle networks with glowing reports of how liveable the city was and how enjoyable it was to visit?

Adaptation

Climate change is already here. Globally we are experiencing the consequences of intense floods and precipitation events, sea level rise, droughts, and heat waves that will continue to increase over the coming decades.

Landscape architects can help communities adapt and be resilient to these changes in a variety of ways.

When oceans get warmer; it means more storms, and when storms move over warmer waters; the intensity of the storm increases; as does the wind intensity. Global warming relocates precipitation in an unpredictable way; which also leads to more drought and unseasonal weather events.

Managing water effectively will be a significant challenge as the atmosphere and our seas continue to increase in temperature. Extreme precipitation events on the coast has highlighted the risk of densely populated cities and vulnerable communities being there. Coastal flooding coupled with sea level rise will threaten communities across the globe.

In the last decade we have seen a variety of projects emerge out of the US’s Rebuild by Design initiative, some of which are currently under construction. These projects which include breakwater systems which also act as new natural habitats demonstrate the unique role design can play in protecting coastal communities against flooding, and offer an exciting alternative to old school attempts at managing similar weather events with walls, concrete, and asphalt.

Landscape architects also play a key role in managing flooding threats in catchment areas and near natural inland water bodies. In effect we need to replicate the hydrologic cycle and daylight stormwater systems, and in doing so it gives us opportunity to create new riparian habitats. We also need more nature based solutions and to make landscaped surfaces more permeable and create new green infrastructure to manage, slow down, infiltrate and attenuate stormwater runoff.

We need to be in sync with our natural system and turn our cities into sponges.

Heat is another growing threat posed by the warming of the planet’s average surface temperature. Higher than normal temperatures are becoming more regular and extensive; creating risk for communities who are not used to extreme heat. The heat also prolongs drought while it also increases risk of intense and extreme wildfires and causes greater water evaporation in regions where there is already water scarcity.

Thinking about the urban heat island is something that needs considered thought. There are a number of strategies that can be implemented to improve thermal comfort in urban areas. Employing shade systems, new green infrastructure, water cooling systems and selecting low albedo materials all make a difference. Combining these strategies can reduce the temperature of a hot urban space by 10° to 12°Celcius.

Over the last decade there has been mass losses in biodiversity due to seasonal shifts, changing temperatures, new rainfall patterns, and extreme weather events. Added to this other human activities such as pollution and general environmental vandalism has damaged natural habitats; meaning that countless species have migrated to seek sanctuary in new locations.

Large scale projects and masterplans have the capacity to be havens for wildlife and are an opportunity to preserve and create new ecological infrastructure for vulnerable species. We need to take a holistic approach that places ecology at the heart of our design. It includes interventions to manage invasive species, restore wetlands, protect critical natural water sources, and enhance wildlife connectivity, while also considering improving access for the general public so they can be connected to nature.

Summary

By incorporating climate-resilient designs, such as water-efficient landscapes, urban green spaces, and sustainable stormwater management systems, landscape architects can contribute to reducing heat island effects, improving air quality, and enhancing overall environmental resilience. They can also collaborate with urban planners, architects, and policymakers to create climate-conscious urban designs that prioritize sustainability and adaptability.

Furthermore, landscape architecture can contribute to raising awareness about the importance of preserving natural ecosystems, promoting sustainable land use practices, and fostering community engagement in climate change mitigation and adaptation efforts.

Overall, landscape architecture's unique position to blend design, ecology, and sustainable principles makes it a valuable profession in tackling the challenges posed by climate change.

References

Columbia University Earth Institute

www.earth.columbia.edu

Landscape Architecture Foundation

www.lafoundation.org

NASA; Global Climate Change

www.climate.nasa.gov

The Climate Change Review, Ethan Olson, 2022

www.theclimatechangereview.com

The Landscape Institute, 2021

www.landscapeinstitute.org/blog/australian-landscape-architects-make-difference-climate-positive-design

United Nations Climate Change