日期: 2019 年 7 月 29 日

人类每年消耗的自然资源都超出自然界的负荷能力，今年地球上的自然资源如水源、土壤和干净空气的配给额，提前于7月29日耗尽，透支情况每年越来越严重。

世界自然资源耗尽日，也叫地球超负荷日，是环保专家们计算出人类耗尽一年自然资源的日子。这一天之后，人类将进入“寅吃卯粮”模式，自然界的再生能力已不能满足人类的需求。

总部位于美国加州的环保组织“全球生态足迹网络”周一（29日）发布声明指出，与20年前相比，地球超负荷日已提早两个月到来，今年是有史以来最早的一次，提前至7月29日。这意味着人类现在消耗自然资源的速度，比地球生态系统能再生的速度快1.75倍，等同于需要1.75个地球才能满足人类的消费需求。

声明说：“全球生态系统超支的情形变得愈来愈明显，这体现在森林被砍伐、土壤流失、生物多样性消失及大气中二氧化碳积累。二氧化碳又导致气候变迁及更加频繁出现极端气候现象。”

全球生态足迹网络希望通过计算每一年的世界自然资源耗尽日，告诫世人自然资源被过度消耗。

自1986年开始计算以来，这个里程碑式的日子每年都提早到来。1993年的地球超负荷日落在10月21日，2003年是在9月22日，2017年提前至8月2日。

全球生态足迹网络创始人瓦克尔纳格说：“我们只有一个地球，这是最终决定人类存亡的因素。我们用了1.75个（地球）之后，不可能不产生毁灭性后果。”

联合国气候变化纲要公约第25次缔约方大会（COP25）定于12月在智利圣地亚哥举行，身为大会主席的智利环境部长施密特表示，地球超负荷日不断提前的主要原因在于二氧化碳排放量持续增加。她说：“显然的，采取果断行动变得越来越重要。”

全球生态足迹网络也发布每一个国家耗尽一年自然资源的日子。比如，德国今年5月3日已经进入自然资源的超支状态。全球范围内，四分之一国家和德国一样属于高消耗国家。如果全人类都像德国人一样消耗自然资源，那就需要三个地球才能满足人类的需求。相比之下，全球资源消耗如果平均达到美国的水平，人类则需要多达五个地球；如果平均为中国的水平，则需要2.2个地球。

Mankind will have used up its allowance of natural resources such as water, soil and clean air for all of 2019 by Monday (July 29), a report said.

The so-called Earth Overshoot Day has moved up by two months over the past 20 years, and this year’s date is the earliest ever, the study by the Global Footprint Network said.

The equivalent of 1.75 planets would be required to produce enough to meet humanity’s needs at current consumption rates.

“Earth Overshoot Day falling on July 29 means that humanity is currently using nature 1.75 times faster than our planet’s ecosystems can regenerate. This is akin to using 1.75 earths,” the environmental group, which is headquartered in Oakland, California, said in a statement.

“The costs of this global ecological overspending are becoming increasingly evident in the form of deforestation, soil erosion, biodiversity loss, or the buildup of carbon dioxide in the atmosphere. The latter leads to climate change and more frequent extreme weather events,” it added.

Calculated since 1986, the grim milestone has arrived earlier each year.

In 1993, it fell on Oct 21, in 2003 on Sept 22, and in 2017 on Aug 2.

“We have only got one Earth – this is the ultimately defining context for human existence. We can’t use 1.75 (earths) without destructive consequences,” said Mr Mathis Wackernagel, founder of Global Footprint Network.

Ms Maria Carolina Schmidt Zaldivar, Chile’s environment minister and chair of the Climate COP25 scheduled this December in its capital Santiago, said a major cause of the date falling earlier and earlier was growing amounts of carbon dioxide emissions.

“The importance of decisive action is becoming ever more evident,” she said.

Individuals can get involved by calculating their own ecological footprint at http://www.footprintcalculator.org

Source: Zaobao / The Straits Times

欧洲炎热天气蔓延到北部，北欧几个国家的气温都创新高，部分地区出现“热带夜晚”。世界气象组织警告，热浪接下来将侵袭格陵兰岛，加速冰川融化，可能打破2012年的融冰记录。

挪威气象研究所周六发推文说，挪威北部当天气温高达35.6摄氏度，追平内斯比恩于1970年创下的全国最高温纪录。南部则有20个地点出现“热带夜晚”，这意味着有关地区一整晚的气温都维持在20摄氏度以上。

瑞典多个地方上周也出现“热带夜晚”，北部气温更创下1945年以来的最高温。瑞典气象水文研究所指出，北方城镇马库斯温沙26日的气温达34.8摄氏度，是瑞典今年以来的最高温。该研究所气象专家约珀兰说：“那是自1945年以来最北地区的最高温，也是历来第三高温。”

该研究所还发布缺水预警，预告全国21个省中，有15省下个月可能面临水供不足的问题。

格陵兰岛冰层或加速融化
挪威、瑞典和芬兰当局已发布热浪警报，芬兰警方还提醒驾车人士小心驾驶，避免撞上麋鹿，因为有越来越多麋鹿穿越公路寻觅水源解渴。

此外，世界气象组织周六警告，随着席卷欧洲的破纪录热浪向北移动，位于格陵兰岛的全球第二大冰层可能会加速融化，厚度接近或低于2012年的最薄纪录，而今年的融化也开始得非常早。

丹麦气象研究所专家莫特拉姆说，热浪预计在北极上空移动，带来大量足以融化冰川的能量。“北冰洋和冰盖表面的海冰，估计会在接下来三到五天内融化。”

Nordic countries are experiencing searing temperatures as Europe’s record-breaking heatwave moves north, the Swedish Meteorological and Hydrological Institute (SMHI) said yesterday, with some areas recording “tropical nights”.

In Sweden, the most extreme heat has headed straight for the country’s far north.

On Friday, the small town of Markusvinsa in the far north recorded a temperature of 34.8 deg C, the highest mark reached in all of Sweden so far this year.

“That’s the hottest temperature in the far north since 1945 and the third-highest temperature on record,” SMHI meteorologist Jon Jorpeland told Agence France-Presse.

Last week, several places in Sweden experienced “tropical nights”, meaning that temperatures stayed above 20 deg C throughout the night.

The tropical heat was also being felt in other Nordic countries, and the Norwegian Meteorological Institute said yesterday that it had recorded “tropical nights” in 20 different locations in southern Norway.

Heat warnings have been issued in Sweden, Norway and Finland, and last week, Finnish police even warned motorists to be mindful of moose, which were increasingly crossing roads in search of water to quench their thirst.

Meanwhile, the heatwave that smashed national temperature records in Belgium, Germany and the Netherlands, and which baked Paris in its highest-ever temperature of 42.6 deg C in the middle of last week, has dissipated a little, but many travellers faced disrupted journeys.

The mercury dived in France with outbreaks of drizzle as state weather service Meteo-France lifted red alerts imposed in 20 departments.

In Germany, the country’s highest mountain Zugspitze – standing at 2,962m – was still almost completely covered in snow despite a national temperature record of 42.6 deg C in the north on Thursday.

“The thick snow cover has provided a buffer against (the mountain) absorbing the high temperatures this year,” a spokesman for the research station at Zugspitze said.

Commuters and holidaymakers saw travel plans blighted with disruption to air and rail services in several European countries.

Flights at London’s Heathrow and Gatwick airports were cancelled and delayed – some by more than two hours – with holiday destinations such as Alicante, Rome and Lisbon affected.

Elsewhere in the British capital, there was still travel havoc due to rails buckling under the heat and fires breaking out along commuter lines.

The Met Office advised against non-essential travel.

At Paris’ Gare du Nord, an electrical failure halted domestic and international high-speed trains during Friday lunchtime, including Eurostar and Thalys services, although traffic gradually resumed.

Thalys – which links Paris to Brussels, Amsterdam and Cologne – also saw disruption, with slow trains amid fears that infrastructure could overheat.

At the peak of the heatwave, temperatures on the tracks soared to up to 15 deg C higher than that of the air.

In Switzerland, train engineers painted rails white to reflect the heat of the sun.

In northern and central France, the heatwave has been particularly brutal in the countryside, aggravating fires which have seen thousands of hectares of crops destroyed.

“More than 3,200ha have already gone up in flames since the start of summer,” Interior Minister Christophe Castaner said.

Source: Zaobao / The Straits Times

美国与欧洲近日相继出现极端热浪。科学家警告，全球极端气温已逼近人体耐热极限，当湿球温度超过摄氏35度以致人体排汗散热失调，恐让中东、南亚及中国华北平原不适宜居住。

湿球温度指的是当前环境仅通过蒸发水分所能达到的最低温度，以反映水分蒸发能力。

英国劳柏罗大学气候科学家马修斯指出，当气温超过摄氏35度，人体靠排汗让体温保持在安全值。但当湿球温度达35度时，人体的调节系统就难以运作。

马修斯说：“湿球温度包含水分蒸散的冷却作用，因此通常较天气预报的正常气温（即干球温度）低得多。一旦超过湿球温度门槛，空气里就会饱含水汽，让汗液无法蒸发。”

这意味人体无法降温到足够程度，几小时内就会身亡。

他指出：“这无关喝多少水、躲在多阴凉的地方或休息多久，无法排除体热，身体核心温度就会上升。”

马修斯说，气候变迁让世界部分人口最密集的区域恐在本世纪结束前超出湿球温度门槛，波斯湾地区、南亚以及中国华北平原首当其冲，成为不适宜居住地带，这些地区加起来，人口达数十亿。

冷气是抗暑的最后防线之一，却有大量耗电问题。马修斯表示，到了2050年，冷却系统带来的用电增加，相当于现在美国、欧盟、日本加总起来的用电量，十分惊人。

马修斯认为，眼下的挑战严峻，但人们能拿出的相应办法却有限，因此温室气体排放必须降至巴黎气候协定的限制，这样才有机会扭转致命的高温。

Extreme global temperatures are pushing the human body “close to thermal limits”, according to a climate scientist.

Record-breaking heat has swept through Europe this week with temperatures topping 40C in a number of countries.

However, in places such as South Asia and the Persian Gulf, people are already enduring temperatures reaching up to 54C.

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 vapour that sweat no longer evaporates,” he said.

This means the human body cannot cool itself enough to survive more than a few hours.

“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.

There is already evidence wet bulb temperatures are occurring in Southwest Asia.

With climate change starting to profoundly alter weather systems, rising temperatures could soon make parts of the world uninhabitable.

If electricity can be maintained, living in chronically heat-stressed conditions may be possible but a power outage could be catastrophic.

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.

“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.”

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.

“In this way, we have the greatest chance of averting deadly heat – home and abroad.”

Source: Zaobao / Independent