温室效应是什么?

What is the Greenhouse Effect?
::什么是温室效应?

Some consider the greenhouse effect a controversial issue. Can it be denied that something is causing a change in global climate ? Is the planet getting warmer? Is it warm in a greenhouse? What happens if you place the planet in a "greenhouse?"
::一些人认为温室效应是一个有争议的问题。 是否可以否认某种物质正在导致全球气候的改变? 地球是否变暖了? 在温室中变暖了吗? 如果你把地球放在“ 温室” 里会怎么样?

The Greenhouse Effect
::温室气体效应

On December 10, 2007, the Intergovernmental Panel on Climate Change (IPCC) and former US Vice President Al Gore received the Nobel Peace Prize “for their efforts to build up and disseminate greater knowledge about man-made climate change, and to lay the foundations for the measures that are needed to counteract such change.” The Peace Prize is designated “to the person who shall have done the most or the best work for fraternity between the nations, for the abolition or reduction of standing armies and for the holding and promotion of peace congresses ." A high honor, the award also announced to the world that climate change ( Figure ) is a critical issues for the future of the Earth and its people. What is climate change? What are its causes? How do its effects relate to world peace? What are “the foundations for the measures that are needed to counteract such change”? Can individuals like us help? These are the questions we will explore in this last lesson about human ecology .
::2007年12月10日,政府间气候变化问题小组(IPCC)和美国前副总统戈尔(Al Gore)获得诺贝尔和平奖,“因为他们努力积累和传播更多关于人为气候变化的知识,并为对付这种变化所需的措施打下基础。” 和平奖被指定给“应该为国家间友好、废除或裁减常备军队、举行和促进和平大会作出最大或最佳努力的人” 。 一项崇高的荣誉是,该奖还授予世界,即气候变化(Figure)是地球及其人民未来的关键问题。 气候变化是什么原因? 气候变化的影响与世界和平有何关系? 其影响与世界和平有何关系? 和平奖是“为对付这种变化所需措施的基础? 象我们这样的人能帮助吗? 这些是我们将在最后的人类生态学教训中探讨的问题。

What is the Greenhouse Effect?
::什么是温室效应?

The greenhouse effect is a natural feature of Earth’s atmosphere – yet another service. Without the greenhouse effect, Earth’s surface temperature would average -18 ^o C (0 ^o F) – a temperature far too cold to support life as we know it. With the greenhouse effect, Earth’s surface temperature averages 15 ^o C (59 ^o F), and it is this temperature range to which today’s diversity of life has adapted.
::温室效应是地球大气的自然特征 — — 又是另一种服务。 没有温室效应,地球表面温度将平均 — — 18°C(0°F) — — 温度太低,无法支撑我们所知道的生命。 温室效应是地球表面温度平均为15°C(59°F ) , 而正是这一温度范围使当今生活的多样性适应了这一温度范围。

How does this ecosystem service work? The greenhouse effect is summarized in Figure . Of the solar radiation which reaches the Earth’s surface, as much as 30% is reflected back into space. About 70% is absorbed as heat, warming the land, waters, and atmosphere (you may recall that only about 1% is converted to chemical energy by photosynthesis). If there were no atmosphere, most of the heat would radiate back out into space as infrared radiation. Earth’s atmosphere, however, contains molecules of (H ₂ O), carbon dioxide (CO ₂ ), methane (CH ₄ ), and ozone (O ₃ ), which absorb some of the infrared radiation. Some of this absorbed radiation further warms the atmosphere, and some is emitted, radiating back down to the Earth’s surface or out into space. A balance between the heat which is absorbed and the heat which is radiated out into space results in an equilibrium which maintains a constant average temperature for the Earth and its life.
::这一生态系统服务如何运作? 温室效应在图中被概括。 在到达地球表面的太阳辐射中,有高达30 % 的反射回太空。 大约70 % 被热吸收,使陆地、水域和大气变暖(你可能记得只有大约1 % 被光合作用转换为化学能源 ) 。 如果没有大气,大部分热会以红外辐射的形式再次辐射到太空。 然而,地球大气层中含有吸收一些红外辐射的(H2O)、二氧化碳(CO2)、甲烷(CH4)和臭氧(O3)的分子。 其中一些吸收的辐射进一步温暖了大气层,而有些则被排放,再向地球表面或空间辐射回。 吸收的热与向空间辐射的热之间的平衡在平衡中维持了地球及其生命的恒定平均温度。

If we compare Earth’s atmosphere to the atmospheres which surround Mars and Venus ( Figure ), we can better understand the precision and value of Earth’s thermal equilibrium. Mars’ atmosphere is very thin, exerting less than 1% of the surface pressure of our own. As you might expect, the thin atmosphere cannot hold heat from the sun, and the average surface temperature is -55 ^o C (-67 ^o F) – even though that atmosphere is 95% CO ₂ and contains a great deal of dust. Daily variations in temperature are extreme, because the atmosphere cannot hold heat.
::如果我们将地球的大气层与环绕火星和金星的大气层(图 ) 进行比较,我们就能更好地了解地球热平衡的精确度和价值。 火星的大气层非常薄,所施加的压力不到我们自身表面压力的1%。 正如你可能预计的那样,薄的大气层无法承受太阳的热量,而平均地表温度是 - 55oC(-67oF ) — —尽管大气为95%的二氧化碳,含有大量的尘埃。 日常的温度变化是极端的,因为大气无法保持热量。

In contrast, Venus’ atmosphere is much thicker than Earth’s, exerting 92 times the surface pressure of our own. Moreover, 96% of the atmosphere is CO ₂ , so a strong greenhouse effect heats the surface temperature of Venus as high as 500 ^o C, hottest of any planet in our solar system. The thick atmosphere prevents heat from escaping at night, so daily variations are minimal. Venus’ atmosphere has many layers which vary in composition, and scientists have identified a layer about 50 km from the surface which could harbor liquid water and perhaps even life; some scientists propose that this would be a reasonable location for a space station. Near this altitude, pressure is similar to the Earth’s sea level pressure, and temperatures range from 20 ^o C to 37 ^o C. Nitrogen, though only 3.5% of Venus’ atmosphere, is present in the same overall amounts as on Earth (because the density on Venus is so much greater); oxygen, however, is absent, and sulfuric acid would present challenges.
::相比之下,金星的大气层比地球的大气层要厚得多,比地球的表面压力高出92倍。 此外,96 % 的大气层是二氧化碳,因此强烈的温室效应将金星表面温度升至500摄氏度,这是太阳系中最热的一个星球。 厚的大气层防止热量在夜间逃逸,因此每天的变化是最小的。 金星的大气层有许多层,其构成各异,科学家们已经确定了距离表面大约50公里的层,可以容纳液态水,甚至生命;一些科学家建议这是空间站的合理位置。 接近这一高度,压力类似于地球的海平面压力,温度介于20摄氏度至37摄氏度之间。 氮气虽然只占维纳斯大气层的3.5 % ,但与地球的总量相同(因为维纳斯的密度要大得多 ) ; 但是氧却不存在,硫酸将构成挑战。

Considering the extremes of greenhouse effects on Mars and Venus, we can better appreciate the precise balance which allows our own atmosphere to provide temperatures hospitable to liquid . Inevitably, we must also ask this chapter’s repeating query: how have human activities affected this equilibrium? This leads us back to the 2007 Nobel Peace Prize, and an evolving consensus that our is responsible for significant .
::考虑到温室效应对火星和金星的极端影响,我们能够更好地理解使我们自己的大气能为液体提供温室温室的准确平衡。 不可避免的是,我们还必须问本章的重复问题:人类活动是如何影响这一平衡的? 这让我们回到2007年诺贝尔和平奖,并逐渐形成一种共识,即我们对重大事件负有责任。

Climate Watch: California at the Tipping Point
::气候观测站:加利福尼亚提金点

The world's climate is changing and California is now being affected in both dramatic and subtle ways. In 2008, scientists determined that California’s temperatures increased by more than 2.1°F during the last century. What’s more, the data showed that human activity has played a significant role in that climate change. "What's just 2 degrees?" you may wonder. But, as the science shows, just 2 degrees is extremely significant.
::世界的气候正在变化,加利福尼亚州现在正在以戏剧性和微妙的方式受到影响。 2008年,科学家们确定加利福尼亚州在上个世纪的气温上升了2.1°F以上。 此外,数据显示人类活动在气候变化中扮演了重要角色。 “只有2度是什么? ”你可能会怀疑。 但是,正如科学所显示的那样,只有2度是极为重要的。

What does all this temperature change mean? For starters, declining mountain snowpack and prolonged drought conditions could pose a threat to limited water supplies. Heat waves are projected to be longer, bringing increased danger from wildfires and heat-related deaths. Rising sea levels due to temperature shifts jeopardize life in coastal areas, both for human communities and the plants and that rely on intertidal and rich wetland ecosystems. Also, more precipitation is expected to fall as rain rather than snow, thereby increasing the risk of floods. And, as heat increases the formation of smog , poor air quality could get even worse.
::所有这些温度变化意味着什么? 首先,山雪不断减少和长期干旱条件可能会对有限的供水造成威胁。热浪预计会更长,导致野火和与热有关的死亡带来更大的危险。 温度变化造成的海平面上升危及沿海地区的生命,无论是人类社区还是植物,它们都依赖潮间和丰富的湿地生态系统。 此外,预计降雨量会随着降雨而不是降雪而减少,从而增加洪水风险。 随着热浪增加烟雾的形成,空气质量可能更加差。

Climate change may also profoundly affect the economy in California and elsewhere. Shorter ski seasons and damage to the ecosystem mean a reduction in tourism. Water shortages mean issues with the commercial and recreational fishing industry, and higher temperatures will affect crop growth and quality, weakening the agricultural industry, to name just a few of the economic issues associated with climate change.
::气候变化也可能深刻地影响加利福尼亚和其他地方的经济。 短短的滑雪季节和对生态系统的破坏意味着旅游业的减少。 缺水意味着商业和娱乐性捕鱼业的问题,高温将影响作物增长和质量,削弱农业,仅举几个与气候变化有关的经济问题为例。

Summary
::摘要

播放段落
• The awarding of the 2007 Nobel Peace Prize to the Intergovernmental Panel on Climate Change (IPCC) and former US Vice President Al Gore recognizes the potential impact of global warming on the economic, social, and political welfare of the world.
  ::将2007年诺贝尔和平奖授予政府间气候变化专门委员会(气专委)和美国前副总统戈尔,承认全球变暖对世界经济、社会和政治福利的潜在影响。
播放段落
• The greenhouse effect is an ecosystem service which warms the Earth to temperatures which support life.
  ::温室效应是一种生态系统服务,可使地球升温到维持生命的温度。
播放段落
• The greenhouse effect involves water, carbon dioxide, methane, and ozone, which absorb heat that would otherwise be radiated out into space.
  ::温室效应涉及水、二氧化碳、甲烷和臭氧,它们吸收本来会辐射到空间的热量。
播放段落
• Earth’s atmosphere maintains an equilibrium between heat added by sunlight and heat lost by radiation.
  ::地球大气层保持阳光加热与辐射损失的热之间的平衡。
播放段落
• The atmosphere of Mars is too thin to hold heat, and that of Venus is so thick that temperatures reach 500 ^o C.
  ::火星的大气层太薄,无法承受热量, 金星的大气层太厚, 温度达到500摄氏度。
播放段落
• In 2000, the major greenhouse gases were CO ₂ , CH ₄ , and NO; CFCs and H ₂ O contribute, as well.
  ::2000年,主要温室气体为CO2、CH4和NO;氟氯化碳和H2O也作出了贡献。
播放段落
• Global warming refers to an increase in the Earth’s temperature of 0.74°C (1.33°F) within the past 100 years.
  ::全球变暖是指地球温度在过去100年内上升0.74°C(1.33°F)。

Review
::回顾

播放段落
1. What is the greenhouse effect?
   ::温室效应是什么?
播放段落
2. Explain the mechanism of the greenhouse effect.
   ::解释温室效应的机制。
播放段落
3. Compare the effects of the greenhouse effect on Mars and Venus to that on Earth.
   ::将温室效应对火星和金星的影响与对地球的影响相比较。