You may not believe that humans could change the planet抯 climate,but the basic science is well understood.Each year,billions of tons of greenhouse gases are released into the atmosphere because of human activity.As has been known for years,these gases holnd heat that would otherwise escape to space,wrapping the planet in an invisible (看不见的)blanket.

　　Of course,the earth’s climate has always been changing due to“natural”factors such as volcanic eruption or changes in solar,or cycles concerning the Earth’s going around the sun.According to the scientific research,however,the warming observed by now matches the pattern of warming we would expect from a build-up of greenhouse gas in the atmosphere梟ot the warming we would expect from other possible causes.t

　　Even if scientists did discover another reasonable explanation for the warming recorded so far,that would give birth to a difficult question.As Robert Henson puts it:揑f some newly discovered factor is to blame for the climate change,then why aren抰 carbonch dioxide and the other greenhouse gases producing the warming that basic physics tells us they should be??The only way to prove with 100% certainty that humans are responsible for global warming would be to run an experiment with two identical Earths梠ne chwith human influence and one without.That obviously isn抰 possible,and so most scientists are careful not to state human influence as an absolute certainty.m

【2016届高考英语二轮复习冲刺模拟卷：（1）（全国卷）】相关文章：

★ 【北京专用】2014届高考英语一轮复习方案课时作业：必修1 Unit 3 Travel journal

★ 山西省永济市涑北中学高三英语总复习：美文欣赏（2）（My Mother）

★ 2017届高考英语二轮复习课时训练：7（含解析）

★ 2017届高考英语二轮复习课时训练：16（含解析）

★ 湖南省汝城二中2014届高考英语一轮复习阅读训练 (13)

★ 2016高考英语听力提升素材

★ 湖南省汝城二中2014届高考英语一轮复习阅读训练 (59)

★ 湖南省汝城二中2014届高考英语一轮复习阅读训练 (2)

★ 四川省2016届高考英语一轮复习课时作业（39） Module 3 Literature 外研版选修8

★ 2013高考英语冲刺-基础篇 词类转换（按考试说明字母顺序）（一）