Showing all editions for 'World English intro: real people, real places, real language', Sort by: Boston, MA: Heinle Cengage Learning: National Geographic. Download for free World English by National Geographic English Course for Adults All Скачать формат (format): PDF, MP3, DVD-Video, CD-exe World English Intro Classroom Presentation Tool; World English Intro and 1 Assessment. World English is an exciting newfour-skills general English series which uses. National Geographic content, images, and video to teach the language that.
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Featuring content from National Geographic and TED, the new edition of the four- level, integrated skills World English series brings amazing stories about our. Writing. National Geographic: I Writing sentences to. "Families around the World" I describe your family. Video Journal. National Geographic: "Animal Families". Aug 13, online pdf format World English Intro and World English 1, ^^pdf download Each DVD features video from National Geographic and TED.
Photograph by Cory Richards In , the Swedish chemist Svante Arrhenius discovered that humans could enhance the greenhouse effect by making carbon dioxide , a greenhouse gas. He kicked off years of climate research that has given us a sophisticated understanding of global warming.
Levels of greenhouse gases have gone up and down over the Earth's history, but they had been fairly constant for the past few thousand years. Global average temperatures had also stayed fairly constant over that time— until the past years. Through the burning of fossil fuels and other activities that have emitted large amounts of greenhouse gases, particularly over the past few decades, humans are now enhancing the greenhouse effect and warming Earth significantly, and in ways that promise many effects , scientists warn.
Aren't temperature changes natural? Human activity isn't the only factor that affects Earth's climate.
Volcanic eruptions and variations in solar radiation from sunspots, solar wind, and the Earth's position relative to the sun also play a role. Changes in solar radiation levels as well as minute particles suspended in the atmosphere from volcanic eruptions , for example, have contributed only about two percent to the recent warming effect.
The balance comes from greenhouse gases and other human-caused factors, such as land use change. The short timescale of this recent warming is singular as well. Volcanic eruptions , for example, emit particles that temporarily cool the Earth's surface. But their effect lasts just a few years. On the other hand, the types of global temperature fluctuations that have contributed to ice ages occur on a cycle of hundreds of thousands of years.
For thousands of years now, emissions of greenhouse gases to the atmosphere have been balanced out by greenhouse gases that are naturally absorbed. As a result, greenhouse gas concentrations and temperatures have been fairly stable, which has allowed human civilization to flourish within a consistent climate.
View Images Greenland is covered with a vast amount of ice—but the ice is melting four times faster than thought, suggesting that Greenland may be approaching a dangerous tipping point, with implications for global sea-level rise. Photograph by Michael Melford, Nat Geo Image Collection Now, humans have increased the amount of carbon dioxide in the atmosphere by more than a third since the Industrial Revolution.
Changes that have historically taken thousands of years are now happening over the course of decades. Why does this matter? Also, a new and more unpredictable climate poses unique challenges to all life.
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