章节大纲

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  • 全球变暖的原因和影响

    A dry field with hay bales, illustrating marginal farming conditions affected by climate change.
     

    What is the human cost of warmer temperatures?
    ::暖温的人类代价是什么?

    Many lands are marginal for farming. When rainfall is normal or high, the lands can produce. When rainfall is low, no crops grow.  Drought  makes marginal lands unsuitable for farming. Drought can also make good lands more difficult to farm. These changes will become more common as temperatures increase.
    ::当降雨量正常或高时,土地可以生产; 当降雨量低时,没有作物种植; 干旱使边际土地不适合耕种; 干旱也使好土地更难耕种。 随着气温升高,这些变化将变得更加普遍。

    Causes of Global Warming
    ::造成全球升温的原因

    Although there have been ups and downs over time, the average global   has been rising since the end of the Pleistocene. Rising temperatures are natural for this time period, but natural causes cannot explain all the warming that's been happening. There is some other factor at work.
    ::尽管随着时间的推移,全球平均气温一直在上升,但自Pleistocene的结束以来,全球平均气温一直在上升。 气温上升是这一时期的自然现象,但自然原因并不能解释所有变暖发生的原因。还有其他一些因素在起作用。

    Recent   is due mainly to human actions which release  greenhouse gases  into the  atmosphere . Greenhouse gases, such as carbon dioxide, keep the atmosphere warm When humans burn  fossil fuels  for  energy , carbon dioxide is released into the atmosphere. The more carbon dioxide in the atmosphere, the better the atmosphere can trap  heat . In other words, an increase in greenhouse gases leads to greater  . The result is increased global warming. Pictured below is the increase in carbon dioxide since 1960 ( Figure   ).
    ::最近主要由于人类将温室气体排入大气的行动。温室气体,如二氧化碳,使大气保持温暖。当人类燃烧化石燃料以换取能源时,二氧化碳就会释放到大气中。二氧化碳在大气中越多,大气层就越容易捕捉热量。换句话说,温室气体的增加将导致更大的热量。结果导致全球变暖加剧。下面是1960年以来二氧化碳的增加(图 )。

    Graph showing carbon dioxide concentration increase from 1960 to 2017, peaking at 406.78 ppm.
     
    How much more carbon dioxide was in the air in 2010 than in 1960?

    Burning forests also releases carbon dioxide into the atmosphere. Other human activities release greenhouse gases into the atmosphere. For example, growing rice and raising livestock both produce methane.
    ::燃烧的森林还将二氧化碳释放到大气中,其他人类活动将温室气体释放到大气中,例如,种植大米和饲养牲畜都会产生甲烷。

    Effects of Global Warming
    ::全球变暖的影响

    Many effects of global warming have already been observed. As Earth has gotten warmer,   and sea ice have melted. This has raised the level of   in the oceans by about 3 mm per  year .  Although this doesn’t sound like much, added together over the years it can be a lot: global  sea level  in 2021 was about 21-24 cm higher than it was in 1880. The rate of sea level rise is now accelerating, and   predict that sea level is likely to rise an additional 30 cm by 2100.   Storm  surges from more frequent  , combined with higher sea levels, means that many coastal communities will face danger from   in the coming decades.
    ::全球变暖的许多影响已经观测到了。随着地球变暖,海冰融化了。这每年将海洋的温度提高约3毫米。 虽然这听起来并不多,但多年来加起来可能很多:2021年全球海平面比1880年高出21-24厘米。 海平面的上升速度正在加速,预计到2100年海平面可能会再上升30厘米。 风暴潮从更频繁的海平面上升,再加上海平面升高,意味着许多沿海社区在未来几十年将面临危险。

    Graph showing sea level changes from 1993 to 2016, highlighting trends and data points.
     
    The overall trend in sea level from 1993 to 2016; it rose about 60 millimeters in that time span.

    The extent of Arctic sea ice in summer has been decreasing rapidly. The ice pictured below is the sea ice minimum in 2016 ( Figure   ). The yellow line is the median minimum ice extent for 1981–2010.
    ::夏季北极海冰的范围正在迅速缩小。 下面的冰面是2016年的海冰最低量(图 ) 。 黄线是1981-2010年的中位最低冰度。

    Map showing Arctic sea ice extent in 2016 with median line from 1981-2010.
     
    The sea ice minimum for 2016 (pictured) was the third lowest on record, with 2012 as the lowest. 2017 was slightly higher, although records have not been updated.

    Other effects of global warming include more extreme  . Earth now has more frequent and severe storms, floods, heat waves, and droughts than it did just a few decades ago. Many living things cannot adjust to the changing  climate . Coral  reefs  in many parts of the world are struggling to survive.  Species  are moving to where temperatures are cooler, often to higher latitudes or higher  altitudes . Those that already live in cold climates are losing  habitat . The timing of migration and egg-laying behaviors in birds is shifting. There are many more examples of the effects of changing climate.
    ::全球变暖的其他影响包括更极端。地球现在比几十年前更频繁、更严重的风暴、洪水、热浪和干旱。许多生物无法适应变化的气候。世界许多地方的珊瑚礁都在挣扎生存。物种正在迁移到温度更低的地方,往往更高的纬度或更高的高度。已经生活在寒冷气候中的物种正在失去栖息地。鸟类迁徙和产卵行为的时机正在改变。气候变化的影响的例子更多。

     

    Summary
    ::摘要

    • Greenhouse gases trap heat in the atmosphere. Burning fossil fuels and other human activities release greenhouse gases into the atmosphere.
      ::燃烧化石燃料和其他人类活动将温室气体释放到大气中。
    • Greenhouse gas levels in the atmosphere are increasing. Global temperatures are increasing.
      ::大气中的温室气体水平正在上升,全球气温正在上升。
    • Changes due to increasing temperatures are seen around the globe. Living organisms and humans are also affected.
      ::全球各地都可以看到气温上升引起的变化,生物体和人类也受到影响。

    Review
    ::回顾

    1. What do you expect to happen if you increase the amount of greenhouse gases in the atmosphere?
      ::如果你增加大气中的温室气体数量 你会有什么后果呢?
    1. What has happened to the level of carbon dioxide in the atmosphere in the past several decades (use numbers and units)?
      ::过去几十年中大气中的二氧化碳水平(使用数量和单位)发生了什么情况?
    1. What has happened to sea level since 1870 (use numbers and units)?
      ::自1870年以来海平面(使用数量和单位)发生了什么情况?
    1. What are some of the effects of climate change that are already being seen?
      ::已经看到的一些气候变化影响是什么?