How to cool a warming world?

How to cool a warming world?

The world is getting hotter. Oppressive heat now stretching coast to coast. Canada, the US, Cyprus, India, Iraq and Kuwait have seen scorching temperatures in the past week. But though the dangers of rising temperatures are well documented less is known about the knock-on effects of keeping cool. Air conditioning is one of the worst consumers of electricity. It heats the planet. At least 7% of greenhouse gas emissions come from cooling and with temperatures likely to soar, this will only worsen. The more the Earth warms the more people need air conditioners but the more of those we have, the warmer the world will be. Cooling saves lives and facilitates education and economic growth in the world’s hottest countries. It also brings huge environmental risks.

How can we keep cool without warming the planet?

Yes, quiet is the word for this new 1954 RCA air conditioner. Air conditioning and refrigeration systems changed the world. They fueled economic expansion transformed, how food and medicines are stored and transported and helped save thousands of lives. But in doing so, they’ve become a major contributor to global warming. Air conditioners are bad for the environment in a couple of ways. Together with electric fans they already account for around 20% of the total electricity used in buildings. America is one of the biggest culprits. The electricity uses for air conditioning is equivalent to the total electricity consumption of the continent of Africa. The problem with air conditioners guzzling so much electricity is that much of the world’s power grids are still fired up by fossil fuels like coal, and so it contributes to the greenhouse-gas problem in a very big way. What’s more, most air conditioners and fridges use man-made gases such as hydrofluorocarbons or HFCs, as a cooling medium. These gases tend to leak into the atmosphere where they are thousands of times more potent at trapping heat than carbon dioxide. And demand for air conditioning is still rising.

Urbanization

 A big reason is urbanization as populations around the world come out of poverty and into modest or middle-class lives. One of the first things people want to buy is an air conditioner. Currently, some 2bn AC units are in use around the world, most across just a handful of countries. But in the tropics over 90% of the 3bn or so people who live there have yet to buy an AC unit. As temperatures and wages rise, demand for AC is predicted to skyrocket. By 2050 around two-thirds of the world’s households could have air conditioning which means without policy intervention emissions are projected to rise by 90% above 2017 levels by the year 2050. We have to find a better way, a more energy-efficient and climate-friendly way of cooling the Earth’s population, or else this is going to be real trouble in future. The race is on to solve the cooling conundrum. With innovative new methods being trialled from technology to make air conditioners more efficient to completely eradicate the need for HFCs. One company developing a radical new method for cooling is a Stanford University spin-out called Sky Cool. On a supermarket roof and deploying Sky Cool technology with their refrigeration system. So our technology works by using the sky itself as a heatsink and so whether it’s sunny out or not, day or night the sky is very cold and what our technology can do is use that cold upper atmosphere to cool things on the surface of the Earth with no input electricity. And so by orienting these panels towards the sky they’re able to send out more heat than they take in from our atmosphere. Sounds, well, pretty cool, but Sky Cool so far has only been installed in a handful of places, despite having plans for more. Innovation is fantastic, but as with the latest iPhone. The poorest people in the world are not likely to get the latest kit. They’ll be the least able to buy those efficient, innovative models that are now coming out. Nascent technology like this can’t be relied upon alone to provide affordable cooling on a mass scale. More solutions are necessary. So there’s a lot to be said for reducing demand for mechanical cooling in the first place through improved buildings better urban design and nature-based approaches.

Building Designs

 Designing buildings so they don’t need air conditioning may be part of the answer. After all, that’s how it was done before AC was invented Pre-World War II buildings were designed to be passively cooled. They had windows that opened. They looked at ventilation and how it moved through the building and our standards of comfort were a little different Between 1946 and 1955 nearly 1.5m homes were constructed every year in America. This building boom brought about cooling complications Post-World War II we see this explosion in the use of air conditioning in buildings. The race for skyscrapers takes over. Who can be the tallest? Who can be the biggest? It becomes a competition. We can’t open the windows at those higher heights so now these hermetically sealed buildings require even more cooling load. But today, innovative building design is providing solutions to keep buildings cool without relying on air conditioning.

Floating Design

The floating office in Rotterdam, which houses the Global Centre on Adaptation is a green architect’s dream. It’s powered off-grid, heated by solar panels, cooled by the river beneath it and made mostly from wood. So let’s go inside and I’ll show you how it works. So here we are, actually inside the floating foundation of the floating office and what we see here is all the technology that cools the building. We use the concrete of the barges and we do that by pumping cooling liquid through pipes that are in the concrete. The ceiling is cooling so through the ceiling, there are the same pipes that are also going through the concrete. So the water is actually in these pipes cooled by the concrete and then it’s being pumped through the ceilings. The Global Center on Adaptation is the largest floating office in the world but although its exact cost isn’t known it’s rumoured to have been expensive to build. And with Rotterdam’s average summer temperature only around 18°C, some might argue that keeping a building cool in this climate isn’t hard. Projects like the Global Centre on Adaptation are impressive and they’re great that they exist, if only for their stand-out technology and their beautiful design. But what we need are scalable, deployable solutions that are affordable and that we can do everywhere. In Cairo, Egypt, where temperatures regularly surpass 35°C the need for scalable and sustainable cooling systems. has never been more urgent.

Experimental Solution

The heat stress that we are facing is a real wake-up call Sarah El Battouty and her company E-Consult were recently awarded funding from Ashden a climate-solutions charity, for their innovative cooling designs. So you can imagine how much material we now have. She takes inspiration from traditional cooling techniques that have been used by communities for centuries. If you go to desert communities or communities in rural Cairo you’re astonished by the level of cooling and they do it by knowing exactly the correct ratios to build how thick the walls are Incorporating some of these age-old techniques in the design of new buildings can drastically reduce the need for air conditioning. To avoid the heat, you don’t go in from the desert to the door immediately. You walk in, into an entryway that is very dark and it’s cooler than the desert. And then the difference is three to four degrees before you enter a room inside. From a building’s orientation to the use of local stone that stays cool drawing on local knowledge could help more communities find sustainable and scalable alternatives to air conditioning 4,500 miles south in Cape Town, South Africa cheap adaptations to existing buildings can also reduce the need for AC. In one community, roofs made of corrugated iron heat up like an oven during the summer months, so they’ve painted them white. In the same way that on a hot day, you might wear a hat or on a hot day might wear white to reflect heat our buildings can kind of do the same thing just by putting out a white reflective coating on these roofs. We can reflect most of that heat and what it does is it will not only cool the building down but cool the neighbours around it down as well. That’s because white roofs can reflect sunlight better meaning the roof itself can stay about 30°C cooler making the internal temperature 2 to 5°C less than a building with a roof painted another colour, like grey. Green buildings cannot be high-end because extreme heat doesn’t only affect people on the high end it affects everybody in various ways. So there needs to be a building that caters to this kind of solution for all income strata. While cheap improvements to walls, roofs and windows could reduce the energy needed for cooling. Small-scale initiatives don’t go far enough. Far-reaching policies and the large-scale ambition to implement them are what is needed to bring about change. Some governments are responding to the challenge Eleni Myrivili was appointed Europe’s first chief heat officer for Athens in 2021. Her job is to come up with sustainable cooling solutions for all of the city. This summer was extraordinary in the sense that it started with a heatwave in June. We had these wildfires taking place at the same time so not only was it difficult to breathe the skies were dark, and clouds were grey and red It felt like a post-apocalyptic scene from a movie. Like many cities, Athens suffers from the urban heat-island effect due to trees and plants being replaced with asphalt and concrete which absorb and then release heat into the air. Here, the average annual land-surface temperatures of urban areas can get up to 3.8°C hotter than in non-urban areas at midday. Eleni is trying to mitigate this by turning some of the city’s streets into pedestrianized tree-lined corridors. So when this is changed and it becomes a pedestrian green corridor somebody walking down the street will have a different experience much more thermal comfort, as we say, because it’s going to feel up to two or two and a half degrees cooler than the rest of the city. Eleni’s team plan to create three green corridors across Athens over the next two years and she plans to make the most of the cooling greenery that’s already there. We’ve been focusing on supporting the existing green areas that we have the existing urban forest parks and the hills supporting the trees and making sure that we have more of them and replenish the nature that we already have. Multiple studies have shown that increasing green areas in cities is crucial to reducing temperatures and the need for air conditioning. If we can create more efficient ways of cooling we’ll be able to bring down emissions linked to buildings, as well as those from air conditioners. The work that Athens is doing in thinking about cooling the city is very powerful and needs to be replicated in other places. The urban heat-island effect is a serious phenomenon and it’s only going to get worse it’s most likely to affect disadvantaged communities the most.

Adaptations

Several cities are making adaptations like Athens Paris plans to have 50% of the city covered by planted areas by 2030. Medellin in Colombia has already won awards for its green corridors and Ahmedabad in India has been acknowledged for its heat action plan the first of its kind in South Asia. We have to think of solutions that are sustainable and that are resilient and this means that we have to think of cooling the whole city so that the building is cooler so that we don’t need so much heating and cooling by using fossil-fuel-dependent appliances. And this is extremely important because if we continue like this again, we’re going to see just higher temperatures and higher temperatures and more crazy climate phenomena. Implementing the city-wide and Implementing country-wide solutions needed to cool the planet sustainably will require cooperation on an unprecedented scale. This is going to require industry, government, finance and civil society to work together. We both have to deploy the most efficient technologies existing as well as invent new technologies so that we have an opportunity for the developing world to leapfrog ahead to a cooler and brighter future.

Thank you