热浪和617888九五至尊娱乐变化

Occasional heat waves have always been an aspect of summer weather in most of the United States. 但随着617888九五至尊娱乐变化，热浪变得更加强烈和频繁, 我们需要认识到随之而来的危险和健康风险.

在接下来的几十年中, every region of the US is expected to experience hotter temperatures and more frequent and 强烈的 heat waves. 不断恶化的高温对健康构成严重威胁, 尤其是对小孩和老人, 建筑和农业工人, 以及那些生活在城市核心地区的人.

这两份资料总结如下:

• 的 最新的617888九五至尊娱乐 关于极端高温是如何变化的，随着全球气温的上升，这种变化可能会继续下去
• 电流和电位 极端高温对人的影响
• How these changes could be curtailed if we take action to reduce the heat-trapping emissions we're putting into the atmosphere

极端高温基础知识

“热浪,“过热事件。,“高温警告”,” “hot spell”—extreme heat has many different names but generally refers to temperatures that are either exceptionally high relative to typical local conditions or reach levels that may be harmful to human health or infrastructure. When extreme daytime temperatures persist over a prolonged period (usually at least two days), 它通常被称为热浪.

人体暴露在高温下会出汗来降温. 在潮湿的环境下, 汗液蒸发得不那么快，身体的降温能力也会受到影响. 热应激会导致和, 如果没有解决, 会导致中暑和中暑等与热有关的疾病吗. 的 impacts of temperature extremes on human health and well-being are therefore generally considered in concert with humidity to measure 热应激条件人体难以自行降温的疾病.

现在和最近的极端高温

Extreme heat events can be measured in a few different ways: the maximum temperatures hit (强度), 事件发生的频率(频率), 或者持续多久(持续时间). 20世纪30年代的沙尘暴时期保持着峰值频率的记录, 强度, and duration of heat waves across much of the United States to this day—but the frequency and 强度 of heat waves have increased in the last several decades in many regions.

除了极端温度的变化之外, studies of heat stress trends over the late 20th to early 21st century found increases across much of the country in the conditions that cause heat stress for humans. In a study of changes in extreme 热应激条件 at 187 weather stations across the US between 1949 and 2005, 20%的监测站记录了一天的数量大幅增加, 极端热压力事件(1961年至1990年相对于本地情况). 平均, these stations recorded 12 more days with extreme heat stress per year in 2005 than they did in 1949.

极端高温的未来

在接下来的几十年里, 如果碳排放继续增长, most of the country could see 20 to 30 more days annually with maximum temperatures above 90 degrees Fahrenheit. 东南部地区可能遭受更严重的打击，可能还会持续40到50天这样的天气.

By 2100, 美国各地都可能经历更多的热浪, 东南偏南, 西南, 阿拉斯加的增幅可能最大. 这些热浪不仅会更加频繁, 它们也会比我们今天所经历的更热. 如果碳排放继续大幅增加, the hottest daily temperatures that occur in a given year in the United States are likely to increase by at least 10°F as compared to the end of the 20th century.

极端高温对健康的影响

高温是美国最致命的极端天气灾害之一. 当暴露在足以提高身体核心温度的高温下, 热应激性疾病——包括热痉挛, 中暑, 中暑是可能发生的.

患有热痉挛的人会经历肌肉疼痛或痉挛. 中暑会导致头晕、脉搏微弱、恶心和昏厥. 最严重的与热有关的疾病, 中暑, 当一个人的体温上升到103华氏度以上时就会发生. Increased daily air temperatures or periods of extended high temperatures have also been shown to increase cardiovascular mortality, 呼吸的死亡率, 心脏病发作.

一些美国居民因极端高温而面临更大的健康不良影响和死亡风险. 低收入居民, 年轻人和老年人, 建筑和农业工人, 有既往病史的个人, and people living in the center of urban areas can be more vulnerable to physical harm from heat.

极端高温对日常生活的影响

极端高温会影响日常生活的许多方面，包括:

• 去上学—的 effect of hot conditions on kids diminishes their ability to learn and lowers their performance on tests. 低收入和少数族裔学生受到的影响尤为严重, and research suggests that this is in part because they are more likely to attend schools and live in homes without air conditioning.
• 517888九五至尊娱乐以外的——数百万居住在美国的人主要从事户外517888九五至尊娱乐——建筑工人, 警察, 农场工人, 军事人员, 盖屋顶, 邮政工人, 园艺工人, 当气温飙升时，其他的人也面临着热应激的风险.
• 住在城市里-城市居民在617888九五至尊娱乐变化中面临着独特的与热有关的风险. 除了经历全球气温上升的影响, 由于城市热岛效应，城市局部温度升高. Cities are hotter primarily because they contain an abundance of heat-retaining materials and surfaces, 比如沥青, 人行道上, 和水泥.
• 在农村生活-热应激对农村居民的生计也有重大影响. 例如, 热应激会对作物生产产生负面影响, 因为它会对几个过程产生不利影响, 包括开花和光合作用. 热应激对家畜养殖户来说也是代价高昂的.
• 旅行-许多类型的基础设施受到极端高温的影响, 包括我们的道路, rails, 还有航空旅行. 凤凰城2017年的热浪, 例如, led to dozens of flight cancellations when temperatures increased to 119°F—above the operable limit of several types of aircraft

我们能做些什么?? 防止极端高温的最坏后果

By stabilizing global carbon emissions in the next few decades (so that atmospheric carbon dioxide remains below 550 parts per million by 2100), the frequency of heat waves the US is likely to see around mid-century would be reduced by approximately 50 percent, compared to a scenario in which carbon emissions continue to increase rapidly through to 2100.

If the global community pursues aggressive emissions reductions in line with the Paris Agreement goal of keeping warming below 3.6°F, the hottest daily temperatures that occur each year in many parts of the country are likely to increase by just 3.6华氏度，而不是10华氏度，与高排放情景相比.

Individuals and communities need policies and infrastructure that take better account of more frequent, 强烈的, 以及更持久的极端高温. 例如, in the coming decades increased reliance on air conditioning to cope with extreme heat is likely to contribute to increased global warming emissions, 空气质素恶化, and an increase in air pollution–related mortality unless we more aggressively invest in clean energy technology, 节能, 以及能效措施.

Existing policies also need to be leveraged and new policies enacted to better help people—particularly outdoor workers, 孩子们, 低收入及少数群体, 老年人, 运动员——应对极端高温. 确保所有户外517888九五至尊娱乐者安全的政策, 文件化或其他形式, 扩大公共冷却设施的使用和意识只是两个例子.