Joy English · Nivel C1 · El medio ambientejoy-english.com

Un fragmento de conferencia sobre la isla de calor urbana

Nombre:Fecha:

Una profesora universitaria explica por qué las ciudades son más cálidas que el campo, sopesa posibles soluciones y se pregunta quién sufre más.

Audio y corrección de respuestas: https://joy-english.com/es/listening/urban-heat-island-lecture

Actitud, opinión e inferencia

Escucha y elige la mejor respuesta. Algunas respuestas no se dicen de forma directa.

What is the lecturer's main purpose in this extract?
- a) To argue that cities should be abandoned in summer
- b) To explain how air conditioners are designed
- c) To introduce a familiar urban problem and assess ways of dealing with it
- d) To compare city life with life in the countryside
According to the lecturer, what is the main cause of the heat island effect?
- a) The heat produced by engines and air conditioners
- b) Surfaces that absorb sunlight and release the heat after dark
- c) A lack of wind in the centre of cities
- d) The large number of people living close together
What does the lecturer imply when she says "Had planners understood all this a century ago"?
- a) The problem might have been avoided with better knowledge
- b) Planners a century ago deliberately ignored the evidence
- c) Modern planners no longer face this problem
- d) Older cities were cooler than modern ones
What is the lecturer's attitude to planting trees?
- a) It is the cheapest and fastest solution
- b) It rarely makes any difference at all
- c) It should be replaced by pale roofs everywhere
- d) It is helpful, but only under certain conditions
What disadvantage of pale roofs does she mention?
- a) They make indoor rooms too cold
- b) They cost more than planting trees
- c) They can create glare for people in the street
- d) They raise the temperature of nearby streets
Why does she say the heat island is "a question of fairness"?
- a) Rich neighbourhoods refuse to plant trees
- b) The hottest areas are often home to people least able to cope
- c) Older residents prefer hotter streets
- d) Parks are always built in poorer areas
Why does she mention cool rooms in libraries?
- a) To suggest that libraries should stay open at night
- b) To prove that technical solutions never work
- c) To criticise cities that paint roofs white
- d) To show that a simple, cheap measure can be valuable
What does the lecturer ask the students to do for next week?
- a) Compare two case studies and judge which approach is better
- b) Paint a roof white and measure the result
- c) Write a report on air conditioners
- d) Interview residents of hot neighbourhoods

Escucha los detalles

Escucha otra vez y escribe la palabra o el número que falta. Puedes escribir los números con palabras o con cifras.

On a calm, clear night, a city can be as much as ___ degrees warmer than the countryside.
Plants help to cool the air because they lose ___ through their leaves.
A study of ___ districts tested the effect of pale roofs.
Pale roofs lowered indoor temperatures by roughly ___ degrees.
During heatwaves, some cities open cool rooms in public ___.

Respuestas

Actitud, opinión e inferencia

c) To introduce a familiar urban problem and assess ways of dealing with itPresenta la isla de calor, explica sus causas y luego sopesa varias respuestas, incluidos sus inconvenientes.
b) Surfaces that absorb sunlight and release the heat after darkDice que los motores y los aparatos de aire acondicionado contribuyen solo en parte; el factor más importante son superficies como la piedra y el asfalto.
a) The problem might have been avoided with better knowledgeLa estructura "Had ... understood, they might have designed differently" sugiere que, con conocimiento, el diseño anterior podría haber sido mejor.
d) It is helpful, but only under certain conditionsDice que los árboles funcionan, pero solo donde hay espacio para las raíces y agua; un árbol que apenas sobrevive puede no enfriar nada.
c) They can create glare for people in the streetDice que las superficies reflectantes pueden proyectar deslumbramiento hacia la calle, lo cual no es lo ideal para los peatones.
b) The hottest areas are often home to people least able to copeSeñala que las calles más calurosas son las que tienen menos parques y que a menudo es donde viven los residentes mayores y de bajos ingresos.
d) To show that a simple, cheap measure can be valuableDice que las salas cuestan muy poco y pueden salvar vidas, por lo que ilustran una respuesta barata y no tecnológica.
a) Compare two case studies and judge which approach is betterLes pide que lean dos estudios de caso y decidan qué enfoque les resulta más convincente, y por qué.

Escucha los detalles

eight / 8La profesora dice que la diferencia puede llegar a ser de hasta ocho grados.
waterDice que las plantas pierden agua por las hojas, lo que extrae calor del aire.
twelve / 12El estudio que menciona abarcó doce distritos.
three / 3Redujeron las temperaturas en unos tres grados.
librariesDice que algunas ciudades han abierto salas frescas en bibliotecas públicas.

Transcripción

Doctor Haddad: Good morning, everyone. Today I want to look at a phenomenon that most of you will have felt without ever naming it: the urban heat island. In essence, a city is warmer than the countryside around it, and on a calm, clear night the difference can reach as much as eight degrees.

Doctor Haddad: Why does this happen? Not, as is often assumed, because cities generate so much heat of their own. Engines and air conditioners do contribute, but their share is modest. The larger factor is surface. Stone, brick and asphalt soak up sunlight all day and release it slowly after dark, whereas soil and vegetation stay cooler, partly because plants lose water through their leaves, which draws heat out of the air.

Doctor Haddad: Why does the night matter so much? Because the body needs a cool period in which to recover. When nights stay hot, people sleep badly, and the health effects build up over days rather than hours.

Doctor Haddad: Had planners understood all this a century ago, they might have designed very differently. Instead, we inherited streets lined with dark surfaces and hardly any shade. Rarely do we stop to consider that a single paved car park can raise the temperature of an entire neighbourhood by a degree or more.

Doctor Haddad: Now, a word of caution about the solutions. Planting trees is the obvious answer, and it does work, but only where there is room for roots and a reliable supply of water. A tree struggling in a narrow pavement pit may cool nothing at all. Pale roofs are cheaper and quicker. In a study of twelve districts, they lowered indoor temperatures by roughly three degrees. Yet reflective surfaces can also bounce glare into the street, which is hardly ideal for pedestrians.

Doctor Haddad: What I find most interesting, however, is the question of who bears the burden. Heat is not shared evenly. The hottest streets tend to be those with the fewest parks, and those are often where older residents and low-income families live. So the heat island is not merely an engineering puzzle; it is a question of fairness.

Doctor Haddad: I'm not suggesting that every problem has a technical fix. Some cities have simply opened cool rooms in public libraries during heatwaves, which costs very little and may well save lives. Others have asked residents to paint their own roofs white, with mixed results. For next week, I'd like you to read the two case studies on the reading list and decide which approach you find more convincing, and why.