How does extreme heat affect your body? - Carolyn Beans

翻译人员: Sabrina Wang 校对人员: Bruce Wang

The year is 2050 and your morning is not off to a good start.

这一年是 2050年，而你的早晨 却不是一个很好的开始。

School is closed for yet another heat day,

学校又因为高温停课，

meaning the kids need to stay home and the AC needs to stay on.

意味着孩子们得待在家里， 空调也要一直开着。

Your usual babysitter can’t come help

你平常的保姆不能来帮忙，

because the rails for their commuter train were warped by the heat.

因为高温把她通勤火车的铁轨 都烤变形了。

And to make matters worse, your dog is desperate for a walk,

更糟糕的是， 你的狗迫切希望散步，

but the pavement is hot enough to give third degree burns

但地面热得足以让任何 接触到它的爪子

to any paw or person that touches it.

或是行人，烫出三度烧伤。

In many parts of the world, this sweltering future is already here.

在世界的许多地方， 这样炎热的未来已经成为现实。

On average, heat waves are happening more often with greater intensity

平均而言，热浪发生的频率 越来越高，强度越来越大，

and for longer durations.

持续的时间也越来越长。

But according to a 2022 projection,

但是根据2022年的预测，

by 2050, Earth’s mid-latitudes could be experiencing extreme heat

到2050年，地球中纬度地区 每年可能会经历

between 90 and 180 days a year,

90到180天的极端高温，

with tropical regions enduring even more.

热带地区的高温天数甚至更多。

So, how hot is too hot, and what can people do to handle the heat?

那么到底多热才算太热呢？ 人们该如何应对高温呢？

While human bodies are decent at managing temperature,

虽然人体在调节体温方面还算不错，

our cooling mechanisms only work under the right conditions.

但我们的散热机制只能在 适当的条件下发挥作用。

When air temperatures climb,

当气温升高时，

the hypothalamus tells blood vessels near the skin to widen,

下丘脑会告诉皮肤附近的血管扩张，

allowing more blood to flow near the body's surface and release heat.

让更多的血液流向 人体表面附近并释放热量。

This hormonal cascade also turns on our sweat glands.

这种荷尔蒙级联反应也会 激发我们的汗腺。

As sweat evaporates, it pulls the heat from our skin.

当汗水蒸发时， 它会从皮肤带走热量。

But if humidity is high, the rate of evaporation slows and eventually stops.

但是，如果湿度过高， 蒸发的速度会减慢并最终停止。

Scientists use this principle to track humidity with a metric

科学家们利用这一原理， 采用了一种指标来追踪湿度，

called wet-bulb temperature,

把它叫做“湿球温度”。

in which they wrap a wet, room temperature cloth around a thermometer

他们用一块常温的湿布

包裹温度计，

to see if evaporation will lower the reading.

看蒸发是否会降低读数。

If it doesn't, it's too humid for sweat to cool us off.

如果没有降低，说明湿度太高， 汗水无法帮我们降温。

A wet-bulb temperature of roughly 35°C

湿球温度大约达到35°C时，

is generally considered the limit of human survival,

会普遍被认为是人类生存的极限，

though current temperatures rarely reach this threshold.

尽管目前的气温很少达到这一极限。

The US National Weather Service uses the relationship between humidity

美国国家气象局使用 湿度和气温之间的关系

and air temperature as the basis for their heat index.

作为热指数的基础。

As those two metrics rise, so too does the heat index;

当这两个指标上升时， 热指数也会上升；

and heat is considered dangerous

如果指数超过 39.4°C，

if the index climbs above 39.4°C.

就被认为是危险高温。

That’s 103°F.

这相当于 103 华氏度。

But even a lower heat index can be hazardous over multiple days.

但即便是较低的热指数，持续多天 也可能是有害的。

A heat wave is a streak of two or more days of unusually hot weather

热浪是指在某地某个季节 连续两天或以上

for a place and season.

出现异常高温的天气。

For example, a string of 32°C days in Houston, Texas,

例如，在德克萨斯州的休斯顿， 32°C的连续高温

is standard in the summer,

在夏季很常见，

but would constitute a heat wave in March.

但如果出现在三月， 就是热浪的形成。

And the impact of these events touches nearly every aspect of daily life.

这些事件的影响几乎涉及到 日常生活的方方面面。

Imagine a June heat wave strikes a tropical city.

想象一下，一场六月的热浪 袭击了整个热带城市。

The first to experience effects are outdoor workers.

首先感受到影响的是户外工作者。

Their excessive sweating leads to dehydration and muscle pain

他们出汗过多会 导致脱水和肌肉疼痛，

known as heat cramps.

也就是所谓的热痉挛。

If they push on, their conditions could worsen

如果他们继续扛下去， 情况可能会恶化

to heat exhaustion and even heat stroke—

导致中暑，甚至是热射病 --

a life-threatening ailment that occurs when a body’s temperature exceeds 40°C.

这是一种当人体温度超过 40度时发生的危及生命的疾病。

Medical emergency calls spike across the city,

整个城市的医疗紧急电话激增，

often for children and people who are pregnant or elderly.

通常是为儿童、孕妇或老人拨打的。

The heat also increases hospital visits for heart, kidney,

高温还会增加因心脏、肾脏

and lung-related conditions,

和肺部疾病而就诊的人数，

creating an influx of patients that threatens to overwhelm medical providers.

从而导致患者大量涌入， 让医务人员不堪重负。

Over the following week, the city slows to a crawl.

在接下来的一周里， 整个城市陷入停滞状态。

Schools and construction sites close.

学校和建筑工地关闭。

Airplanes need to reduce their weight limits to take off,

飞机必须减少起飞时的重量限制，

bumping countless travelers from their flights.

导致无数旅客被迫取消航班。

Restaurants shut down as overheated kitchens become unbearable.

过热的厨房让人难以忍受， 餐馆纷纷停业。

Residents who remain inside with air conditioners stay safe.

在室内使用空调的居民 虽能保持安全，

But blasting AC isn’t cheap,

但是老吹空调并不便宜，

and many families have to choose between keeping cool and staying fed.

许多家庭不得不在保持凉爽 和维持温饱之间做出选择。

Either way, if the heat continues,

无论如何，如果高温持续下去，

the stress of these air conditioners could overwhelm the power grid,

大量使用空调所致的压力 可能会使电网不堪重负，

potentially leading to city-wide outages.

甚至导致全城停电。

These consequences are all very real.

这些后果都是非常真实的。

Each year, close to 500,000 people die due to excessive heat,

每年有近50万人死于过热，

and these extreme conditions are only growing more common.

而这些极端情况 正在变得越来越常见。

We can limit medical impacts by seeking help for heat-related illnesses,

我们可以通过寻求 与过热相关疾病的帮助、

staying hydrated,

保持水分、

and keeping people cool through public access to water and AC.

以及通过使用公共供水、空调 让人们保持凉爽来控制疾病的影响。

But don’t let anyone tell you 1 to 2 degrees doesn’t matter.

但不要让任何人告诉你1到2度的 高温变化无关紧要，

It will change our very way of life.

它会彻底改变我们的生活方式。