Extreme global temperatures are pushing the human body “close to thermal limits”, according to a climate scientist.
一位气候科学家表示，全球极端气温正将人体推向“高温极限”。
Record-breaking heat has swept through Europe this week with temperatures topping 40C in a number of countries.
本周，破纪录的高温席卷欧洲，一些国家的气温超过40摄氏度。
top [tɒp]：v.超过（某一数量）；高过
However, in places such as South Asia and the Persian Gulf, people are already enduring temperatures reaching up to 54C.
然而，在南亚和波斯湾等地，人们忍受的高温已达54摄氏度。
Despite all the body's thermal efficiencies, these areas could soon be uninhabitable, according to Loughborough University climate scientist Dr Tom Matthews in The Conversation.
When air temperature exceeds 35C, the body relies on sweating to keep core temperatures at a safe level. However, when the “wet bulb” temperature – which reflects the ability of moisture to evaporate – reaches 35C, this system no longer works.
“The wet bulb temperature includes the cooling effect of water evaporating from the thermometer, and so is normally much lower than the normal (“dry bulb”) temperature reported in weather forecasts,” Dr Matthews wrote.
“Once this wet bulb temperature threshold is crossed, the air is so full of water vapor that sweat no longer evaporates,” he said.
他说：“一旦湿球温度超过阈值，空气中就充满了水蒸气，汗水就不再蒸发了。”
threshold ['θreʃəʊld]：n.门槛；临界值
This means the human body cannot cool itself enough to survive more than a few hours.
这意味着人体不能自我降温，这种情况持续几个小时就能危及生命。
“Without the means to dissipate heat, our core temperature rises, irrespective of how much water we drink, how much shade we seek, or how much rest we take,” he explained.
Some areas – which are among the most densely populated on Earth – could pass this threshold by the end of the century, according to Dr Matthews.
马修斯博士说，地球上人口最密集的一些地区的湿球温度可能会在本世纪末突破这一阈值。
With climate change starting to profoundly alter weather systems, rising temperatures could soon make parts of the world uninhabitable.
随着气候变化开始深度改变天气系统，不断上升的气温可能很快使部分地区不宜居住。
If electricity can be maintained, living in chronically heat-stressed conditions may be possible but a power outage could be catastrophic.
如果能维持电力供应，长期生活在高热状况下是可能的，但停电可能造成灾难性后果。
In a recent paper published in Nature Climate Change, Dr Matthews and his team looked at the probability of a “grey swan” event in the case of extreme heat coinciding with massive blackouts.
Mega blackouts sometimes follow powerful tropical cyclones. Researchers found that dangerously hot temperatures during a period with no electricity could have catastrophic consequences.
强热带气旋过后，有时会出现大范围停电。研究人员发现，在停电时，危险的高温会带来灾难性的后果。
tropical cyclone：热带气旋
2019年7月25日，法国巴黎
“We looked at tropical cyclones, which have already caused the biggest blackouts on Earth, with the months-long power failure in Puerto Rico after Hurricane Maria among the most serious,” Dr Matthews wrote.
“We found that as the climate warms, it becomes ever more likely that these powerful cyclones would be followed by dangerous heat, and that such compound hazards would be expected every year if global warming reaches 4C.
“During the emergency response to a tropical cyclone, keeping people cool would have to be as much a priority as providing clean drinking water.”
“在应对热带气旋的紧急应对措施中，让人们保持凉爽应该与提供清洁饮用水一样成为当务之急。”
Heat-stressed countries are likely to see the largest absolute increases in humid-heat and they are often the least well-prepared to deal with the hazard. This could drive mass migration, which would make heat a worldwide issue – even for countries that are not experiencing scorching temperatures.
Dr Matthews wrote: “The challenges ahead are stark. Adaptation has its limits. We must therefore maintain our global perspective on heat and pursue a global response, slashing greenhouse gas emissions to keep to the Paris warming limits.
