#microclimate

"A recent World Meteorological Organization report called heat waves the “deadliest meteorological hazard” from 2015 to 2019, affecting people living on all continents, and setting new national heat records in many regions.

‍Canada’s top weather event in 2021 was British Columbia’s record-breaking heat, according to Environment and Climate Change Canada. The temperature in Lytton, B.C., hit 49.6 C on June 29. The following day a wildfire destroyed 90 per cent of the town, killing two people and displacing 1,200 others.

Heat waves also exacerbate existing health issues, including cardiovascular and respiratory disease. They’re associated with increased hospital admissions, psychological stress and aggressive behavior, as well as excess mortality.

During heat waves, the highest temperatures are often found in urbanized areas. Urbanization is almost always associated with an increase in paved, impervious areas, and often a decrease in greenery. Concrete and asphalt roads, and other built materials readily absorb, store and release heat, raising city temperatures, a phenomenon called the urban heat island.

Many studies have shown that urban forests can reduce the urban heat island, and many policies focus their attention on large green spaces.

Small green spaces, such as yards, rooftops and small parcels of undeveloped land, can make impressive contributions to lowering urban heat, but they are often overlooked when developing strategies for urban cooling.

The effect of small green spaces

Cities rarely have the opportunity to add large green spaces to help counter the effects of heatwaves. Smaller vegetated spaces, however, can still meaningfully decrease local land temperatures.

Small green spaces, such as yards, rooftops and small parcels of undeveloped land, can make impressive contributions to lowering urban heat, but they are often overlooked when developing strategies for urban cooling.

A recent study in Adelaide, Australia, found that tree canopy cover and, to a lesser extent, grass cover decreased local daytime surface temperatures by up to 6 C during extreme summer heat conditions. Further inland, suburban yards and gardens can decrease local surface temperatures up to 5 C.

At a quite small scale, on the order of tens of square metres, trees reduced daytime surface temperatures twice as much as grass cover. But grass and other small, low-lying plants, grow relatively quickly, compared to trees.

Cities should adopt short-term and long-term strategies to respond to extreme heat, including the replacement of paved and impervious surfaces with grasses and turf, and increasing tree plantings to boost canopy coverage.

Amplifying the cooling effect

Furthermore, when managing small green spaces, city planners and foresters can select tree species based on their ability to cool the environment. Green spaces with a high diversity of tree species have a greater cooling effect in spring, summer and fall. They also have a larger maximum drop in temperature in the summer, compared to spaces that are less diverse.

For example, tree canopies with large leaves and high transpiration rates — the evaporation of water from plants occurring at the leaves — could provide more cooling.

Planting a variety of species, of different heights, can have a larger cooling effect than tall trees alone.

The structure of green space may also influence its cooling efficiency. In summer, a plant community with multiple layers of trees, shrubs and herbs can further decrease air temperature by 1 C on a sunny day and 0.5 C on a cloudy day, compared with an area only dominated by tall trees...

But overall, trees usually have a stronger effect on cooling than grass. Planting trees in groups, not individually or in lines, is recommended for regulating the microclimate (local climate conditions near the Earth’s surface).

Small green spaces can offer a lot of summer cooling in cities. And cities can learn to manage the configuration of small green spaces better to get more cooling benefits and minimize the trade-offs."

Palm tree silhouetted against mountains in the Sierra Nevada de Santa Marta, Colombia.

The Andes mountains in Colombia, Ecuador, Peru and Bolivia, the Tropical Andes, is considered the most biodiverse region in the world. This is an even more remarkable feat given that it covers less than 1% of the world’s land surface. Nearly one-sixth of all plant life on the planet is found here, and the Tropical Andes is home to more amphibians, birds and mammals than any other Biodiversity Hotspot on the planet. Its incredible biodiversity includes more than 1,500 bird species, nearly 500 reptile species and more than 800 amphibian species.

How does a place like this become home to such diversity of life? The Tropical Andes is part of the longest mountain chain on Earth, and has a wide elevational range, from its lowest point at 1,640 feet above sea level to its highest point standing more than 19,600 feet tall.

Due to this, the climate changes dramatically over short distances, resulting in a remarkable variety of ecosystems. Steep slopes, deep canyons, and wide valleys characterize the Tropical Andes Biodiversity Hotspot. This region and its landscapes have led to the evolution of an amazing diversity of species and habitats: rainforests and cloud forests, grasslands and scrublands, alpine, and the unique ecosystems of paramo and puna.

Its proximity to other biodiversity hotspots and wilderness areas like the Tumbes-Choco in Magdalena, Colombia or Amazonia , further contribute to the high diversity of the region.

Cities are home to all forms of life, not just humans

Urban Reef designs and creates open-ended habitats that encourage the growth and diversity of life in urban settings such as streetscapes, squares and buildings. To live together with more-than-human lifes, urban settings need more room for uncontrolled and emerging ecologies, both physically and in our collective thought.

Our prototypes called "Reefs" are designed to integrate open systems and regenerative design into the city. Reefs are created using bio-based algorithms and are 3D printed with (living) materials. Connected with passive flows rich in sunlight, water, nutrients and minerals, Reefs provide a range of microclimates and store nutrients that benefit more-than-human beings, complementing anthropocentric design approaches of urban environments.