And it's probably easiest to explain why with thermal vision.

最簡單的解釋方法是利用熱成像。

It shows the heat all around me and also the coldness of this ice cream cone.

它顯示出我周遭的熱度，還有這支冰淇淋甜筒的冰冷。

Cities are often hotter than their suburbs due to a phenomenon known as the heat island effect.

城市之所以比郊區炎熱，是因為一個稱作「熱島效應」的現象。

All of that asphalt, concrete, dark rooftops and tall buildings, they absorb and store heat.

城市裡那堆柏油、水泥、暗色屋頂和高樓都會吸收並儲存熱度。

And there are a lot of people using a lot of energy—driving cars, riding subways, running the AC.

並且有很多人都在使用大量能源—開車、搭地鐵、吹冷氣。

All of these materials and activities either create or retain heat.

這些材質與活動要不是製造熱源，就是儲存熱度。

And all that stored heat causes steeper nighttime highs when people would otherwise have a chance to cool down.

而所有積聚下來的熱在夜間造成溫度高峰——人們原本能有機會冷卻下來的。

The way all these heat-storing elements are laid out matters quite a bit.

這些元件本身儲存熱以外，它們如何分布也有關係。

In cities laid out in grids, like Phoenix, Chicago, or Washington, D.C., the buildings are closer together, like closely packed coals in a fire, keeping heat in.

在棋盤式規劃的城市裡，像是鳳凰城、芝加哥、華盛頓特區，建築物彼此更靠近，就像火堆裡緊密相連的煤炭一樣把熱鎖在內部。

More space between buildings creates more circulation.

建築之間若有更多空間，就能促進空氣流通。

Another way to combat this heat island effect is through green space.

另一個避免熱島效應的方法是透過綠色空間。

Parks, trees, plants, they don't absorb as much heat.

公園、樹木、植物，這些都沒有那麼吸熱。

They actually send water back into the atmosphere.

事實上它們還會將水分送回大氣層。

Between all those hot buildings, that cools things off.

在炎熱建築之間把溫度降低。

Another solution is color.

另一個解決辦法是顏色。

Light colors reflect sunlight back into the atmosphere instead of storing it as heat.

淺色系將陽光反射回大氣層，不會保留熱度。

It's easiest to see in crosswalks, and it's true for the color of buildings and other urban surfaces, too.

斑馬線是個很明顯的例子，建築物和其他都市表層的顏色亦同。

And one long-game way to combat the heat island effect is to avoid using air conditioning when you don't need it.

另一項打擊熱島效應的長遠辦法則是在不需要的時候，盡量避免使用冷氣。

AC uses a ton of electricity and creates a feedback loop.

冷氣消耗大量電力，還會製造出一個回饋循環。

When we get that electricity from coal or natural gas, that puts more carbon dioxide into the atmosphere, which warms the planet making cities even hotter.

當我們以煤炭或天然氣產生電能，那會排放更多二氧化碳至大氣層，暖化地球、使城市更炎熱。

But this isn't just about comfort.

但這不僅關係到我們的舒適感受。

Today, heat waves kill more people than any other extreme weather event.

今天比起其他極端氣候現象，熱浪造成的死亡數最高。

More than tornadoes, hurricanes and even floods.

比龍捲風、颶風，甚至水災都還多。

City populations keep growing, and those cities are only getting hotter.

城市人口數不斷增加，那些城市只會越來越熱。

This is Let's Talk, NPR's news explainer show.

您收看的是 Let's Talk 節目，全國公共廣播電台 (NPR) 的新聞解析節目。

Make sure to subscribe to our YouTube channel and check out other shows.

記得要訂閱我們的 YouTube 頻道，也別忘了看看其他節目。

I'm Christopher Joyce, and this is NPR.

我是 Christopher Joyce，這裡是全國公共廣播電台。