#4: Climate Change in Cities - Heat Waves, Water Shortage and Crime Rates

Today's episode is Part 1 of a series about how climate change is affecting our cities. There are four episodes in this series, coming out over the coming months, with a different topic for each.

Today's topic is heat and I cover the following issues:

• What is "Degrees Warming"?
• Extreme heat / heatwaves (Case study: Paris)
• Water shortages (Case studies: Nigeria and England)
• Correlation between heat and increased crime rates

Future episodes in this series will cover water (sea level rise and flooding), food and society. Follow/subscribe to the podcast to stay up to date! Follow us on social media for additional content and news.

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Intro music by Tanoi
https://www.instagram.com/tanoiband

https://open.spotify.com/artist/5CO2UfOc9jkoImoS6Wmsx4?si=HmxCxRYkTreT7XCTW2G51g

References:
Many of the facts and figures come from The Uninhabitable Earth by David Wallace Wells - an amazing book. Specific internet-based resources are shown below.

Heat
https://www.nytimes.com/2019/07/26/world/europe/france-europe-extreme-heat.html
https://www.citylab.com/environment/2019/06/paris-trees-famous-landmarks-garden-park-urban-forest-design/591835/
https://www.citylab.com/environment/2019/06/europe-heatwave-paris-climate-resilience-weather-hot/592729/
IPCC, Climate Change 2014: Synthesis Report, Summary for Policy Makers

Water
https://www.bbc.co.uk/news/uk-47620228
https://www.wired.co.uk/article/london-thames-water-leaks
https://www.circleofblue.org/2018/world/water-scarcity-looms-in-londons-future/#:~:text=In%20recent%20years%2C%20London%20has,is%20influenced%20by%20several%20factors.

Crime
https://www.hks.harvard.edu/sites/default/files/centers/mrcbg/files/ranson_2012-8.FINAL.pdf
https://iopscience.iop.org/article/10.1088/1748-9326/ab6b37/pdf
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2018GH000152
https://onlinelibrary.wiley.com/doi/pdf/10.1002/9781118517390.wbetc198

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The Green Urbanist podcast is created by Ross O'Ceallaigh. 

Transcript

Welcome to the Green Urbanist, the urbanism and sustainability podcast. I'm Ross.

Today's episode is Part 1 of a series about how climate change is affecting our cities. There are four episodes in this series, coming out over the coming months, with a different topic for each.

The topic of today's episode is heat. After that we will look at water, in the form of rising sea levels, flooding and extreme wet weather like hurricanes, after that I'll dive into how climate change is affecting our food on all levels, from the growth of plants in a changing climate to our entire food system. The final episode will look at how our society is changing and how climate change is affecting migration, conflict and our mental health. But right now, let's jump into today's episode.

We're going to look at how our cities are already feeling the impact of heat and how things will be getting worse. But it's not going to be a totally depressing episode. I will offer some case studies throughout of how cities are rising to this challenge and some thoughts on addressing the underlying issues.

But before that, let's just have a quick recap on what it means when we say "degrees warming". I'll use this phrase throughout the podcast, and you've probably heard it in the news; 1 degree of warming, 2 degrees of warming, etc. What does this mean? Why is it important? Essentially, it's a way of measuring the effect of fossil fuel emissions on global temperature.

The Paris agreement, which most developed countries have signed, states that we will aim for 1.5 degrees Celsius of warming from pre-industrial levels and stay well below 2 degrees. To put that in perspective, we are already at 1.1 degree of warming and so are experiencing the beginning effects of climate change. And that doesn't leave us much wiggle room to meet our target.

In fact, if we continue down our current emissions path, the Intergovernmental Panel on Climate Change (the IPCC) predicts 4 degrees of warming by 2100. 

What does this mean? 4 degrees celsius sounds totally insignificant. But the effect of all that extra heat is enormous.

Heat

Let's look at an example. You may remember back in 2003 there was terrible heatwave in Europe that killed 35,000 people. At 4 degrees of warming, that is will be a normal summer. Now, 4 degrees assumes we continue business as usual. I don't see that happening. But even with good progress, we will likely still hit about 2 degrees of warming over the next few decades meaning that that scale of heatwave, which was an exceptional, once in an era event, will become much more common and more expected.

Other parts of the globe will fare even worse, with already sweltering regions of India and Pakistan getting hotter every year.

How can we adapt to this? Some countries do better with the heat by using air conditioning systems. In Saudi Arabia, 700,000 barrels of oil are burned each day during the summer, mostly to power air conditioning. In most of Europe, air conditioning hasn't been necessary but if extreme heat becomes the norm, we may need it just to survive, meaning a huge increase in energy use.

Perversely, the more fossil fuels we burn now, the more we will have to burn in the future to adapt to the resulting extreme weather. Air conditioning already accounts for 10% of global carbon emissions. Some estimates predict that demand will triple or quadruple in the next 30 years. Of course, this may be a bandaid solution for wealthy parts of the planet. But some of the hottest places in the world are also the poorest and so it is simply not a viable solution to air condition large parts of the planet.

For those people who only understand risk as it effects the economy, its worth pointing out that increased temperatures negatively effect productivity and estimates say that increased heat will have a significant effect on city's gross domestic product in coming decades.

I mentioned the european heatwave of 2003 - during that, France was hit particularly badly and afterwards the French government immediately started mitigation plans for future heatwaves. In the summer of 2019, when the country suffered another heatwave, Paris employed some interesting urban design solutions. Before we jump into that, it's worth mentioning that the reason large cities like Paris fare so badly in heatwaves is because of something called the Urban Heat Island Effect. City's are covered in concrete, asphalt, steel and glass and these materials store up heat during hot weather and actually increase the air temperature in cities. It is not uncommon for the centre of cities to be 5 degrees celsius higher than the surrounding countryside. In fact, Paris can be up to 10 degrees hotter, making an already sweltering summer day, dangerously hot. 

So if man made materials increase heat, then surely natural materials can help to cool cities down, or at least reduce this heat island effect. So at the core of Paris's response to the heatwave last summer, was making sure residents had access to this natural source of cooling. The opening hours of parks were extended, many of them open 24 hours 7 days a week. In the longer term, the city is looking to replace as much of these hard surfaces as possible, by installing green roofs, using permeable surfaces on streets and planting trees. Trees are a great way of staying cool because they provide not only shade but also moisture, creating a kind of cooling vapour. Paris is taking this a step further and has plans to plant micro-forests of densely planted trees on small urban sites throughout the city, creating what they call "islands of freshness".

Another really interesting part of Paris's approach is the use of water. Anyone who has taken a dip in the sea on a summers day knows the powerful cooling effect of water. If you've been to Paris you'll probably have noticed that many of the public squares have beautiful water fountains. These permanent fixtures of the city already function to chill the air, cooling people with their mist and, in some places, people can actually get in the water. To boost this, the city installed misting machines in public squares and retrofitted fire hydrants to create mist and to provide drinking water. This use of water is no doubt effective for cooling people down. But water is a limited resource. The next topic I'm going to talk about is the effect climate change is having on water shortages.

Freshwater Shortages

Of all the water on planet earth, approximately 0.007% is both fresh and accessible. There isn't much of it. And yet, technically this much freshwater should be plenty for all of our needs. But access to freshwater around the world is hugely unequal. 2.1 billion people around the world don't have access to safe drinking water and 4.5 billion don't have safely managed water for sanitation. 

This lack of access is a problem that exists outside of climate change. It is a result on poverty, but also bad politics and a lack of investment or maintenance, and also overpopultion in the wrong places. So we have this absolutely essential resource that is not managed properly at all. Then comes along climate change and makes the problem much worse.

What effect is climate change having on our water supply?

As the temperature of the planet is rising, freshwater sources that we have relied on for centuries are evaporating and drying up. For instance, the Aral Sea in central Asia, once the 4th largest lake in the world, has lost 90% of its volume in recent decades. Its not just water bodies though. Some cities rely on a steady rhythm of glacial melt water replenishing water sources in the summer, with the glaciers reforming in the winter. Now, glaciers are simply melting, meaning this very important water source is running out. The United Nations predict by 2050, that 5 billion will not have safe access to freshwater. 

We typically think of water scarcity as being a problem in parts of Africa, conjuring familiar images of rural Africans travelling for miles and miles to the nearest well everyday. And certainly this is true. However, it is often not a problem of poverty but a failure of politics. I visited Nigeria a few years and spent some time in a city called Ibadan. Right in the centre of the city is an old informal, organic settlement that's built up over the years bit by bit. About 2 million of the city's poorest residents live here with no running water, open sewers and often no toilets. This is not because of the underlying climate. Ibadan is not in a desert or a dry climate. In fact 1 in 3 days during the year are rainy and the city often has problems with flooding during the rainy season. Nor is it a problem of a lack of resources. Nigeria is the 27th largest economy in the world and the largest in Africa, so within the country exist the resources to provide water to people as a basic resource. But it doesn't happen. It is a failure of politics. However, as the climate changes and this region of Nigeria gets hotter and drier, it will get harder and harder for people to access any water at all.

We are not immune to this problem in the rainy UK either. The Environment Agency last year gave a stark warning that London and the South East of England will face severe water shortages by 2040. Again, this seems to be only partly fuelled by climate change. In fact, the main causes are a growing population and an old inefficient system of water pipes that is riddled with leaks. I've read one estimate that says that London's pipes are leaking 500 million litres of water a day. Add on top of these problems the fact that climate change is reducing the annual rainfall in England, rainfall that's needed to fill reservoirs, and you've got all the ingredients for severe water shortage.

What is the solution to this?

Well we need to fix these leaks right? That much obvious, and water companies are putting more resources into this but short of replacing thousands of kilometers of pipes, it is not a problem with an easy or quick solution. So why not build more reservoirs? Well, water companies have been trying to build new reservoirs in the south east for decades but a complicated and drawn out regulatory and planning system coupled with fierce local opposition has prevented this essential infrastructure from coming forward. It also doesn't help that in the 1980s when the water company for the area, Thames Water, was privatised, it sold off 25 of its reservoirs. 

Another potential solution is to build a system to connect parts of northern England that have a water surplus with the south-east. But this is far from a quick fix as it can take decades to get these large infrastructure projects through the political and planning system and then just as long to actually build the thing. So the solution we are left with is the UK government and Environment Agency begging people to use less water in their day to day lives. Because the structural barriers to a technical solution are so high, the onus is put on the end users, the consumers and citizens to make do with inadequate infrastructure in the face of climate change. Now, don't get me wrong, it is prudent for all of us to use less water and to not waste water. But how about providing grants for people to retrofit buildings with rainwater harvesting and homes with high efficiency fixtures? Just something to think about.

Within these two examples is the lesson that if there are cracks in our society, climate change will find them and wrench them open. If there is inequality in access to resources like water, then the effect of climate change is to widen that gap even more. It's like rainwater finding the crack in a roof and over time rotting away the timber structure of your house. Yes, the rain caused the damage but if the roof was properly maintained then the problem would have been a lot less severe.

I'm going to look next at an effect of climate change that I'm sure many of you will be surprised about. That is the connection between heat and crime rates.

Crime

It is well documented in criminology and sociology literature that there is a correlation between warmer weather and an increase in crime rates - specifically relating to violent crime and property related crime. When you think about this, it may seem like common sense. Remember the last time there was a summer heat wave, you probably had moments when the heat made you irrationality irritated and angry. You were probably annoyed with the people around you for things that in a normal situation wouldn't bother you at all. Now, imagine you're someone who is already inclined towards violence and criminal activity. The addition of this hot weather may be enough to push you over the edge to assault someone. Researchers have found evidence to support this idea. A classic study from 1976 found that male subjects were more likely to provide an electric shock to someone who just gave them negative evaluation if the ambient room temperature was increased.

But interestingly, this phenomenon does not just occur during very hot weather and it does not just increase the rates of violent crime. When there is unusually mild winter weather, there is often a corresponding spike in property related crime such as burglaries. One of the theories behind this is that certain weather conditions contribute to the ideal conditions for committing certain crimes. So, on a mild winter night, a family may decide that instead of staying in as they usually would, they will take advantage of the nice weather and go out for the evening. An enterprising thief may then use the opportunity to burgle their house.

Now, I don't mean to scare you. It isn't like there is someone constantly watching your house waiting for the right weather to strike. The observed increase in crime levels is small - maybe 2 or 3% of an increase. But it is statistically significant and over a large population, it does result in a noticeable increase in crimes.

But how does this relate to climate change? Well, hotter summers and milder winters are exactly the effects of climate change we are experiencing now and will continue to experience because of climate change. So does this mean that we will see a general increase in crime rates because of the consistently hotter weather and how bad will it be?

A study from Harvard in 2012 asked this question. It looked at the correlation between temperature and crime in the United States and then estimated the future increase in crime linked to climate change over the next century, from 2010 to 2099, presuming a global temperature increase over that time of 2.8 degrees celsius. The study found that the United States will experience an additional 35,000 murders, 216,000 cases of rape, 1.6 million aggravated assaults, 2.4 million simple assaults, 409,000 robberies, 3.1 million burglaries, 3.8 million cases of larceny, and 1.4 million cases of vehicle theft, compared to the total number of offences that would have occurred between the years 2010 and 2099 in the absence of climate change. The present value of the social costs of these climate-related crimes is between 20 and 68 billion dollars.

These figures sound incredibly scary but bear in mind that the US has a high base crime rate compared to other developed countries and we're talking about a long time period of 90 years. So even though the percentage increase across these various crimes is between 1 and 3%, the result is quite staggering.

The author of the paper does concede that the analysis doesn't take into account our potential adaptation to warmer weather and increased crime rates. So for instance, we may see increased crime in the short term but then our behaviour and policing practices could adapt to combat the increase, meaning that in the end, the increase in crime may be nowhere near as bad as this paper suggests.

Or, perhaps society does not adapt well to climate change in the coming decades, resulting in greater and greater levels of inequality and an increase in crime beyond even what this study estimates. Only time will tell.

So what do we do?

This is clearly a problem that goes well beyond urban planning and design.

What this points to is the need for deep deep collaboration across society and particularly in cities as we tackle this problem we call climate change. In the last episode of the podcast I spoke about the need for cities to foster this collaboration and bring all the various actors together. But at the time it didn't occur to me that the police should be part of that discussion. But clearly they do because they will have to adapt their practices to climate change too.

We love talking about design interventions and renewable energy and infrastructure projects but our response to climate change needs to encompass more than that because the problem is reaching into every aspect of our lives in ways that we can't predict.

Well, that's it for Part 1 of this mini series on how climate change is affecting cities. I may have left you with more questions than answers but hopefully you are a bit more informed than when we started. I certainly learned a lot putting together this episode. All the sources for this episode are linked in the description if you want to do any further reading. If you liked the episode, please subscribe to the podcast and follow us on Twitter @greenurbanpod and Instagram @greenurbanistpod where you'll find additional content and news.

Thanks.