How harmful to the climate are air conditioning systems?
It's getting hotter and hotter on Earth. More and more people are using air conditioning to cool down. Large cities in particular are real heat islands. But air conditioning systems consume a lot of energy and harm the climate. Are there alternatives?
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00:00 Take a look at these building facades in Singapore.
00:03 And these in New Delhi, New York and Hong Kong.
00:07 Notice anything?
00:09 In these parts of the world, life without air conditioning can be uncomfortable or downright dangerous.
00:14 More than a dozen people have died in India in the past two months due to a severe heat wave.
00:19 A fierce heat wave.
00:20 Heat wave.
00:21 Heat wave.
00:22 But that brings us to our dilemma.
00:24 The technology needs lots of energy.
00:26 In fact, cooling building accounts for 10% of our global electricity consumption.
00:31 And that's bad news for global warming.
00:33 It's a vicious loop.
00:35 We cool the indoors, but we warm the outdoors.
00:38 Therefore generating the need for more cooling.
00:41 But there are solutions, some traditional, some modern, that don't eat up massive amounts of energy.
00:47 Nowadays, Americans are still some of the most prolific AC users globally.
00:54 90% of US households own an air conditioner.
00:58 In some of the hottest parts of the world, it's not even 10%.
01:02 But other countries want to catch up.
01:05 Just look how much more energy some of these emerging economies are projected to use in the coming decades to cool their homes and buildings.
01:12 If you see India's air conditioning market, it is growing in double digits.
01:17 Ankit Kalanki is working to open up the global market for high-efficiency air conditioners.
01:23 India's population is growing.
01:26 India is getting even hotter.
01:28 But also a large portion of Indian population is urbanizing, is moving to cities.
01:33 And all of that together constitutes a huge demand for air conditioners.
01:38 Because of trends like these, global energy demand for space cooling is projected to triple by 2050.
01:45 The question is how to meet the soaring demand without exacerbating the heat.
01:49 You may have heard of the urban heat island effect.
01:52 It's when urban areas like these get warmer than their surroundings, because all this concrete absorbs and retains heat.
01:59 And there's also lots of waste heat from human activities like transport or, well, air conditioning.
02:04 Creating more spaces with shady trees and other plants lessens this effect.
02:09 Like here in Berlin.
02:11 The Colombian city of Medellin was able to reduce average temperatures by 2 degrees Celsius only three years after planting green corridors.
02:21 The interconnected network of greenery spans dozens of waterways and busy polluted streets.
02:26 And minimizing heat expelled by cars also makes a difference.
02:33 In Spain, Barcelona's superblocks prioritize pedestrians and cyclists.
02:38 But scale matters.
02:40 The city's Institute for Global Health estimates that 117 heat-related deaths could be avoided every year if hundreds more blocks were introduced.
02:49 The next step is designing buildings that aren't as reliant on air conditioners.
02:53 And this is where we can really learn from traditional architecture.
02:57 Before technology, all people around the world found solutions to survive properly.
03:05 Charles Galavardin leads bioclimatic architecture projects in countries like Vietnam and Mauritania.
03:11 That means that designs take local climates into account.
03:15 So we have to study carefully all this vernacular architecture.
03:19 Some modern buildings are already doing this.
03:22 Such as Qatar University, which uses wind towers to keep its buildings cool.
03:26 This method has been used in Iran and other Middle Eastern countries for centuries.
03:31 The so-called wind catchers are designed to trap fresh air and direct it indoors.
03:36 The hot air gets pushed out.
03:38 You may also have noticed that houses in hot climates are often white.
03:42 Some countries like India are bringing back this approach by painting roofs with lime-based whitewash, which absorbs less heat.
03:48 This can reduce indoor temperatures by 2 to 5 degrees Celsius.
03:52 When designing new buildings, bioclimatic architects tend to combine different sources of inspiration.
03:58 But they will all tell you, location is everything.
04:02 You have to pay attention to the sun orientation.
04:06 And make sure your facades are not exposed to the direct sun.
04:11 And then we usually study carefully the wind direction.
04:16 Knowing the wind direction is important to design openings that encourage cross ventilation.
04:21 Other features that can help stave off heat are shading devices that keep the facade cool.
04:26 And insulation prevents heat from traveling through your roof, for example.
04:30 Galavardin says these methods can reduce indoor temperatures by about 5 degrees Celsius.
04:35 While ceiling fans can help circulate this cooler air.
04:39 ACs may still need to be used sometimes, but to a much lesser extent.
04:43 The problem? In many countries going through a construction boom, new buildings often look like this.
04:49 Builders tend to build them with floor-to-ceiling glass.
04:54 And that's a real problem because every time you put glass into a building, you turn it basically into a hot box.
05:02 It's like a solar cooker.
05:05 Architects and engineers say this aesthetic is popular because it's perceived as sleek, modern and lets in natural light.
05:11 Changing that would require more rigorous building regulations around energy efficiency.
05:16 And a massive cultural shift to actually get them enforced on the ground.
05:20 In most of the architecture schools, we are not trained for this.
05:26 When you ingrain that into their business as usual approach, you will get the solutions.
05:32 Another big obstacle is that this approach tackles new constructions.
05:36 But what about all the old, badly insulated buildings that already exist?
05:40 This takes us to our next solution. More efficient air conditioning.
05:44 Because there is no technological reason for ACs to use as much energy as many commercial models do now.
05:51 The AC industry is rooted in a roughly 100-year-old technology.
05:57 It's been working, convenient, you know, at the switch of a button we get cooling.
06:03 This is Neha Satcher. She works to make climate-friendly cooling more accessible.
06:08 There hasn't been a lot of motivation or market factors that have spurred innovation.
06:17 And you really see how wasteful ACs can be in places like India, Singapore or parts of the US.
06:23 Because this is where it often gets humid.
06:26 About a third of the energy is used for managing humidity.
06:31 While some modern models have a so-called dry mode to target humidity,
06:36 Kalanki says air conditioners are still pretty bad at measuring how much moisture is in the air.
06:41 And consequently, how much moisture they need to remove for optimum comfort.
06:45 So, many people simply blast their ACs to overcool the room and get humidity down to a desired level.
06:53 But what if we thought about efficient mechanical cooling on a much larger scale?
06:57 A system like this is already functioning in Singapore.
07:00 Here, an underground air conditioner touted as the largest in the world
07:04 cools residential buildings, banks, malls and this iconic hotel.
07:09 The technology is called district cooling and it can save up to 50% on energy and emissions.
07:16 That's because having one big plant cooling an entire district makes it super efficient.
07:22 The water is chilled 25 meters below the ground before it's piped across different buildings.
07:26 The challenge for district cooling is in terms of infrastructure.
07:32 It's a big capital investment and it requires a lot of infrastructure.
07:39 This may sound utopian, but like all other solutions, it requires lots of upfront capital, know-how and of course, awareness.
07:48 awareness.
07:48 (upbeat music)