科学家称，欧洲部分地区变暖的速度比气候模型预测的要快，欧洲大陆经历了极热天数的激增。
根据发表在美国地球物理联盟杂志上的一项研究地球物理研究快报在过去的二十年里，随着世界变暖，非洲大陆经历了一系列“高影响的极端高温”。
瑞士苏黎世瑞士联邦理工学院的鲁思·洛伦茨领导的一个研究小组发现，在欧洲，极端高温和热应力(一种温度和湿度相结合的测量方法)的平均天数在1950年至2018年间增加了两倍多，而极端高温的天数则增加了2.3摄氏度(1.4华氏度)。)
该研究还发现，欧洲夏季总体上变得更热，而冬季也变暖，在研究期间极端寒冷的日子减少了50%。此外，研究人员称，极端寒冷的天气已经变暖了3摄氏度以上。
该小组说，大约94%的气象站的冷热极端变暖，表明上升是由变暖的气候引起的，而不是自然变化。
“即使在欧洲这个区域范围内，我们也可以看到这些趋势比我们从自然变化中预期的要大得多。这确实是气候变化的信号，”洛伦茨在一份声明中说。
最新的发现是在欧洲打破高温记录的一个夏天。据气象-法国报道，6月28日，法国南部城市蒙彼利埃附近的热浪袭击了欧洲大陆，创下了有史以来最热的一天——46摄氏度(114.8华氏度)。
与此同时，荷兰、德国和比利时的气温都创下了历史最高纪录，分别达到了40.7摄氏度、40.5摄氏度和41.8摄氏度(华氏105.3度、104.9度和107.2度)。捷克共和国、奥地利、波兰、卢森堡、安道尔和斯洛伐克都创下了6月份的最高气温纪录。
为了得出结论，研究人员检查了欧洲气象站在1950年至2018年间收集的观测数据，观察了极端的热、冷和湿度。
洛伦茨说:“我们想调查我们是否能够从观测到的台站数据中检测到极端温度的变暖趋势。”新闻周刊。“我们分析了欧洲观测到的台站数据，并将它们汇总到相对较大的区域。我们观察了前1%最热的日子和热应激日子，后1%最冷的日子，以及每年最热的日子或最冷的夜晚，并观察了它们随时间的变化。”
洛伦茨指出，虽然科学家已经知道欧洲气候正在变暖，但这项研究提供了新的见解。
她说:“这项研究的新要素是在区域范围内的趋势检测，我们能够证明在台站观察到的趋势比自然变化预期的要大得多。”。
“结果是，检测到的趋势信号比单独的温度信号更加明显。我们能够证明欧洲极端冷热的变化比季节平均值的变化更大，不是在任何地方，但例如在中欧，信号非常明显。这些结果实际上并不令人惊讶，但由于气候变化，我们会期待什么，”洛伦兹说。
研究结果还表明，欧洲变暖的速度比气候模型预测的要快，尽管应该注意到存在地区差异。
“在荷兰、比利时、法国，模型趋势比观察到的趋势低两倍左右，”荷兰皇家气象研究所的气候分析师吉尔特·扬·范·奥尔登堡在一份声明中说，他没有参与这项研究。“我们达到新记录的速度比你预期的要快。”
随着全球气候变暖——人类活动已经被认为导致全球气温上升了1摄氏度——欧洲的炎热天数只会随着寒冷天数的减少而增加。这可能对该地区的公共卫生产生重大影响，特别是在那些没有为酷热做好准备的国家。
洛伦茨说:“热应激对人类健康很重要，越来越多的高温应激会影响劳动生产率和死亡率。”。
极端高温的增加绝不仅限于欧洲。最近发表在杂志上的一项研究环境研究交流发现气候变化会导致邻近的美国极端高温的频率和严重程度显著上升未来几十年。
关注科学家联盟(UCS)对当前的热趋势进行了分析，为一份新报告预测未来的气候，发现除非采取严厉措施抑制温室气体排放，否则当热指数——或“感觉”温度——超过105华氏度时，气候变化将导致每年天数的激增。
加州大学洛杉矶分校的高级气候科学家雷切尔·李克此前告诉记者:“酷热是危险的，也可能是致命的——它目前是美国与天气相关的头号死亡原因之一。”新闻周刊。
“我们的研究结果表明，如果不能减少吸热排放，将导致危险热量在美国惊人地膨胀。到本世纪中叶，热量指数超过105华氏度的天数将翻两番，这样全国150多个城市每年平均会有30天或更多的热量指数超过105。
她说:“到本世纪末，美国约有1.2亿人——超过今天人口的三分之一——将经历相当于一周或更长时间的酷热天气，超过国家气象局目前的热指数。”。
一张2019年7月25日欧洲发射热能的卫星图像显示了今年夏天的最高极端。欧空局-哥白尼哨兵数据
'A SIGNAL FROM CLIMATE CHANGE': EUROPE HAS BECOME MUCH HOTTER THAN PREDICTED OVER THE LAST 70 YEARS
Parts of Europe are warming faster than climate models have predicted, with the continent experiencing a spike in the number of days with extreme heat, scientists have said.
According to a study published in the American Geophysical Union journal Geophysical Research Letters, the continent has experienced a series of "high-impact heat extremes," over the past two decades as the world warms.
A team of researchers led by Ruth Lorenz from the Swiss Federal Institute of Technology in Zurich, Switzerland, found that on average the number of days with extreme heat and heat stress—a measure combining temperature and humidity—in Europe more than tripled between 1950 and 2018, while extremely hot days have become warmer by 2.3 degrees Celsius (1.4 degrees Fahrenheit.)
The study also found that European summers have become hotter overall while winters also warmed and saw a 50 percent reduction in extreme cold days over the course of the study period. Furthermore, cold extremes have warmed by more than 3 degrees Celsius, according to the researchers.
The team say that cold and hot extremes have warmed at about 94 percent of weather stations, indicating that the rises were caused by a warming climate, not natural variability.
"Even at this regional scale over Europe, we can see that these trends are much larger than what we would expect from natural variability. That's really a signal from climate change," Lorenz said in a statement.
The latest findings come during a summer which has seen heat records smashed in Europe. France recorded its hottest day ever—46 degrees celsius (114.8 degrees Fahrenheit)—near the southern city of Montpellier on June 28 during a heatwave which struck the continent at the end of that month, according to Meteo-France.
Meanwhile, the Netherlands, Germany and Belgium all recorded their highest-ever temperatures with the mercury reaching 40.7, 40.5 and 41.8 degrees Celsius (105.3, 104.9 and 107.2 degrees Fahrenheit) respectively. The Czech Republic, Austria, Poland, Luxembourg, Andorra and Slovakia all recorded their highest ever June temperatures.
To come to their conclusions, the researchers examined observational data collected by European weather stations between 1950 and 2018, looking at extremes of heat, cold and humidity.
"We wanted to investigate if we are able to detect a warming trend in temperature extremes from observed station data," Lorenz told Newsweek. "We analyzed observed station data over Europe and aggregated them over relatively large regions. We looked at the top 1 percent hottest days and heat stress days and the bottom 1 percent coldest days as well as for each year, the hottest day or coldest night per year and looked how these changed over time."
Lorenz noted that while scientists already knew that the European climate was warming, this study provides new insights.
"The new elements of the study were the trend detection at the regional scale, that we were able to demonstrate that the observed trends at the stations are much larger than expected from natural variability," she said.
"The results were that the detected trend signal was even more pronounced than for temperature alone. And that we were able to demonstrate that changes in hot and cold extremes over Europe are larger than changes in seasonal means, not everywhere but for example in Central Europe the signal is very clear. These results are actually not surprising, but what we would expect due to climate change," Lorenz said.
The findings also suggest that Europe is warming faster than climate models predict, although it should be noted that there are regional differences.
"In the Netherlands, Belgium, France, the model trends are about two times lower than the observed trends," Geert Jan van Oldenborgh, a climate analyst at the Royal Netherlands Meteorological Institute, who was not involved in the study, said in a statement. "We're reaching new records faster than you'd expect."
As the global climate warms—human activities are already thought to have caused an increase of 1 degree Celsius in global temperatures—the number of hot days in Europe is only set to increase as the number of cold days decreases. This could have significant implications for public health in the region, especially in countries which are not prepared for extreme heat.
"Heat stress is important for human health and an increasing number of days with high heat stress can have impacts on labour productivity and mortality," Lorenz said.
Increases in extreme heat are by no means limited to Europe. A study recently published in the journal Environmental Research Communication found that climate change will lead to a significant rise in the frequency and severity of extreme heat across the contiguous United States in the coming decades.
The Union of Concerned Scientists (UCS) conducted an analysis of current heat trends to make predictions about the future climate for a new report, finding that climate change will lead to a spike in the number of days per year when the heat index—or "feels like" temperature—exceeds 105 degrees Fahrenheit, unless drastic action is taken to curb greenhouse gas emissions.
"Extreme heat is dangerous, and it can be deadly—it is currently one of the top weather-related causes of death in the United States," Rachel Licker, Senior Climate Scientist, at UCS previously told Newsweek.
"Our results show that failing to reduce heat-trapping emissions would lead to a staggering expansion of dangerous heat across the U.S. By midcentury, the number of days with a heat index above 105 degrees Fahrenheit would quadruple such that more than 150 cities across the country would experience an average of 30 or more days per year with a heat index above 105.
"By late century, about 120 million people across the U.S.—more than one-third of today's population—would experience the equivalent of a week or more of conditions so hot they exceed the National Weather Service's current heat index scale," she said.
A satellite image of the heat energy emitted from Europe during July 25, 2019 shows this summer's highest extremes.
