Temperature records across history, and the world, have been falling in recent years like giants tripping up over their own shoelaces. World-wide heatwaves suffocate towns, cities, countries and continents under an unbearable blanket of relentless heat. The mercury continues to ascend and globally heatwaves are responsible for thousands upon thousands of deaths. Up to 35,000 people died in European heatwaves in 2003 and the World Health Organisation estimates that in the near future up to 255,000 people could die every year worldwide from heatwaves. This has been underlined by the Earth Policy institute who recently stated:

“Though heatwaves rarely are given adequate attention, they claim more lives each year than floods, tornadoes, and hurricanes combined, Heatwaves are a silent killer, mostly affecting the elderly, the very young, or the chronically ill.”

Earth Policy Institute

And this could become the new normal for summer periods around the world. June temperatures in 2019 broke records around the world, including in Europe, Africa and South America.

Alaska is melting having experienced it’s warmest spring on record (this record has been broken 3 times now in the last 21 years). This will inevitably speed up the rate of global warming with the country itself is warming up twice as fast as the rest of the globe. Accompanied by vanishing sea ice and the less visible but equally devastating impact of permafrost melt. This in turn is accelerating the release of atmospheric carbon; Alaska is the canary in the coal-mine: sounding the alarm and highlighting the potential feedback loops. Scientists are now only beginning to observe and understand these feedback loops as human induced CO2 emissions drive the upward trend of global warming.

What then, are the implications for human societies? How does heat affect our behaviours, the architecture and urban design of our cities? What are the solutions for mitigating heatwaves at both an individual and global level? It’s a complicated problem and one that goes right to the heart of the global warming debate. How do our individual actions as a species contribute to the global warming crisis that is currently enveloping us?

Deadly heatwaves and the Urban Island Heat Effect

The Urban Island Heat Effect is when cities, predominantly, are significantly hotter than their surrounding areas. The main causes are down to the physical properties of an urban environment as compared to a natural environment.  Pavements, roads, roofs and concrete structures are dark in colour and have significantly different properties to vegetation. The concrete and asphalt materials used enable the absorption of heat. This means they absorb more heat which is radiated back into the environment at night. 

High buildings and narrow streets channel the heat into focussed areas which raise the temperature even further, and a lack of vegetation reduces what  little moisture there is in the air (trees give moisture out through their leaves), which would help mitigate against rising temperatures. 

Waste heat from traffic, public transportation, machinery and air-conditioning further exacerbates the problem. The use of air-conditioning, and its huge increase over recent decades, encapsulates the dilemma at the heart of the global warming problem. Allowing individuals to make individual choices, extrapolated to all who can afford air conditioning, creates an exponential trend of increasing energy use. In an effort to keep ourselves cool we create a strange irony which actually increases global temperatures.

Just like car ownership itself, another major contributor to CO2 emissions, the purchase of a car signifies status, wealth and success and is something that a growing middle class around the world will aspire to; ditto aircon. It provides comfort and convenience and yet it is these millions of individual choices that mean countries developing their middle classes for the pursuit of the capitalist dream will only contribute to the problem.

The USA, potentially the most capitalist and individualistic choice-friendly country in the globe consumes more energy in the pursuit of air-conditioned comfort than the rest of the world combined. It demonstrates the difficulties inherent with our current mode of operation and why sustainable development across capitalist societies is an impossible dream.  

Weaning ourselves off air-conditioning and designing mechanisms to keep buildings passively cool is essential if we are to reduce the urban island heat effect and cool workplaces and homes at the same time.

Intelligent design and cooling buildings passively

It would be painfully ironic if our desire to keep cool led to a warmer world. Which is why architecture, design and urban planning need to interwoven into the efforts and solutions to keeping cool.

There are a number of basic age-old principles that have stood the test of time and can help building of the future be designed in a way that keeps temperatures down and occupants cool.

  1. Orientate buildings so that windows face south. This means that the sun’s warmth is limited from entering the interior of the building in tis east to west trajectory and so reduces the level to which the building warms up. 
  2. Shade windows or tint glass to prevent heat from entering the building
  3. Insulate the building – just as good insulation prevents heat from escaping it will also prevent excessive heat from entering. 
  4. Instal a reflective roof – this can help to radiate heat back into the atmosphere and ensure you use materials that are certified to reflect heat and have low emissions.
  5. Design the building to facilitate effective ventilation, ensuring there is a mechanism in palce to remove unwanted heat
  6. Instal low energy appliances, ensuring that emitted heat is kept to a minimum

These are some very basic suggestions about ways in which heat can be controlled and a visual representation from the Master Builders channel on YoutTube shows how this might look in practice:

How planting millions of trees could help save lives in future heatwaves

Nature also has an invaluable role to play. A report titled Planting Healthy Air has outlined how planting millions of trees could help save lives. The cooling effects of trees happens at a local level, so planting trees and allowing them to mature and provide a canopy of tree cover would provide the most benefit in those densely populated areas which are experiencing the highest levels of heat at peak times. And by reducing the dangerous effects of overheating during heatwaves, lives can be saved. 

A study has shown how trees can potentially reduce the temperature in urban crowded cities by a huge 5 degrees and with more than half of the world’s population already living in cities, and growing, this relief can’t come soon enough. 

urban cooling effect

The conclusions from this research seem obvious: where there is shade, as provided by tree canopy, the ground can be up to 5 degrees cooler whilst simultaneously providing an effective sunscreen. This effect is achieved not purely by the shading influence of each tree but also by the fact that trees effectively ‘perspire’. Each tree is pumping gallons of water up from the ground, through its trunk, its branches and its leaves which then feed into the stomata of each leaf, tiny holes a bit like pores, where the tree effectively exhales water. And water vapour from trees (as you can see in the header image) helps to reduce the temperature. 

The urban island effect means that temperatures in cities with ever increasing populations are set to soar and global warming will exacerbate this. It’s essential that urban planners consider the role trees can play so that when they start to design the next generation of urban spaces they can consider how to integrate the world’s oldest and most environmentally friendly plants into the development of urban spaces. 

There are a number of other technologies that could be employed to help cool the air, but trees are the only tool we currently have at our disposal. They have a dual function that helps to clean and cool the air at the same time. Additionally once planted there are very few ongoing costs. There are no energy requirements and no emissions. A mature tree requires pruning, from a safety perspective, but other than that they can provide an invaluable service to our urban spaces.This would help to make them both cooler, cleaner and more aesthetically pleasing places to live. 

Is reducing our CO2 emissions the answer

Inevitably reducing our CO2 emissions is the overarching goal and societies around the world will need to grapple with this in order to stem the rising temperature of global warming.  

The real challenge lies not necessarily in a lack of technology or the unfolding effects of climate change. It’s in the mindset of each and every one of us because only when we completely change on an individual basis what our priorities are will we start to work together collectively to utilise our technologies and combat the causes of climate change. For human-kind to understand how big the challenge of climate change really is we need to realise how environmentally intrusive our lives our. We need to see the truth and take responsibility for the damaging and destructive effects of our lifestyles on the natural environment.

We need to stop waging war on nature.

It is possible for us to make everyday, individual decisions that help to reduce our CO2 emissions and here are the Top 10 ways you might want to try.  These are suggestions that you can implement right here, right now. Until governments and corporations demonstrate the will to change from the ground up it is up to each and every one of us to take the fight to them. 

Ultimately, if we want to live in a world that is not bent over, crippled and destroyed by the devastating impacts of global warming then we have to interrogate the ways in which we are contributing to the problem. Having a clear understanding or our role in this problem, both at an individual, city-wide and global level is the first step towards finding a solution.