IELTS Fluent · Cuối khoá · Listening: Lantern Festival and Urban Heat

Presenter: Good morning, and welcome to What's On, the programme that tells you everything that's happening in and around Millbridge this week. And the big news this weekend is the return of the Millbridge Lantern Festival, which is now in its twelfth year. For those of you who are new to the area, the festival started as a small event organised by a group of parents at the primary school, and it has since grown into one of the biggest celebrations in the region. The organisers are expecting around eight thousand visitors this year.

Presenter: The biggest change this year concerns the main lantern procession. In the past, the procession has always gone through the market square, but because of the building work that's going on there at the moment, it will follow the path along the river instead, finishing at the old stone bridge. The organisers have told me that they actually prefer the new route, as the reflections of the lanterns on the water should look spectacular – but they're keen to stress that the move wasn't their choice.

Presenter: There's another important change, and this one concerns the workshops. Entry to the festival itself is free, as always. However, for the first time, you'll need to book a place in advance if you want to join one of the lantern-making workshops. Last year so many people turned up that families had to queue for over an hour, and quite a few children went home disappointed. Places can be booked online or at the library, and there's a small charge of three pounds per lantern to cover the cost of materials.

Presenter: Now, getting there. If you're planning to drive, please be aware that the car park on Station Road will be closed all weekend. The organisers strongly recommend using the free shuttle bus, which will run every twenty minutes from the leisure centre. Cycling is also encouraged, and there'll be extra bike racks near the bridge.

Presenter: And what about the weather? Well, the procession will go ahead even if it rains – lanterns are covered with waterproof paper these days. The only thing that would stop it is strong wind. If that happens on Saturday, the procession will be moved to Sunday evening at the same time, rather than being cancelled.

Presenter: So let me run through the programme. The lantern-making workshops take place on Saturday morning in the church hall, from ten until one. They're suitable for children aged five and above, and younger children are welcome to watch.

Presenter: Next, there's the storytelling tent, which will be in Elmwood Park – that's E-L-M-W-O-O-D – just behind the library. This year the storytellers will be sharing traditional stories about the moon from different countries around the world, with sessions every hour from midday.

Presenter: The food market will be set up along the river all afternoon, with around forty stalls. This year, all the stallholders have stopped using disposable cups, so please bring your own cup if you'd like a hot drink. You can also buy one at the information point.

Presenter: Then, of course, there's the procession itself. It starts from the primary school at 7.15 pm – that's a quarter past seven – so please be there by seven if you're carrying a lantern.

Presenter: And finally, instead of the usual fireworks, which upset a lot of pets and wildlife last year, the festival will end with a drone light show above the river at nine o'clock. I'm told it's going to be quite something. So, that's the Lantern Festival. Now, let's move on to…

Lecturer: Good morning, everyone. Today I'm going to talk about a problem that affects almost every large city in the world, and which is becoming more serious as global temperatures rise: the urban heat island effect. Put simply, this describes the fact that cities are often several degrees warmer than the countryside around them, especially at night. In the first part of today's lecture, I'll explain what causes it and why it matters, and then we'll look at some of the solutions that cities are trying.

Lecturer: So why does this happen? There are a number of reasons, but the most important is the materials that cities are built from. Dark surfaces such as asphalt roads and roofs absorb a large amount of energy from the sun during the day and release it slowly after dark. And unlike soil and plants, they don't hold water, so there's no cooling from evaporation. Tall buildings also trap heat, because they block the wind. Then there's the heat that we produce ourselves – from vehicles and factories and, increasingly, from air conditioners, which cool the inside of buildings but pump hot air out into the street.

Lecturer: Some people assume that the effect is only a matter of comfort. In fact, the consequences can be serious. During heatwaves, death rates in cities rise sharply, particularly among elderly people living alone. Higher temperatures also increase energy use, because more air conditioning is needed, which creates a kind of vicious circle. But what surprised the researchers in one recent study was the effect on sleep. When night-time temperatures stay high, people sleep less, and this seems to affect their health and their productivity at work almost as much as the daytime heat does.

Lecturer: So what can be done? I'm going to look at three main approaches. The first is what are called cool roofs. These are roofs that are painted white or covered with a reflective material. A cool roof can reflect up to 80 per cent of sunlight, compared with only around 10 per cent for a typical dark roof. In some trials, the temperature on the top floor of buildings fell by as much as three degrees. Cool roofs are relatively cheap, but they do need to be cleaned regularly, because dust and dirt reduce the amount of light they reflect. They have another advantage, too: because the building stays cooler, people use less air conditioning, so their energy bills go down.

Lecturer: The second approach is to increase green space. Trees are particularly effective, because they not only provide shade but also release water vapour through their leaves, which cools the air around them. However, trees take many years to grow, and in dense city centres there is often very little space underground for their roots. That's why some cities are turning to green walls – vertical gardens attached to the sides of buildings. They look attractive, but they're expensive to install, and they require a lot of maintenance, particularly watering in dry periods.

Lecturer: The third approach concerns pavements and car parks. Traditional asphalt can be replaced with permeable paving, which allows rainwater to pass through into the ground below. When the sun comes out, this water evaporates and cools the surface. Permeable paving has the additional benefit of reducing flooding during heavy storms, which is why it's become popular with many local councils.

Lecturer: Now, none of these approaches will solve the problem on its own, and in the second half of the lecture I'll look at how some cities have combined them…