冰川融化英文ppt

1、polar ice cappolar ice cap meltingeffectssolutionscausesHow do they form? At higher latitudes, the earth doesnt receive much sunlight and, therefore the temperatures remain low for most part of the year, thus the water cant remain in liquid form and it solidifies(使凝固使凝固) water turns into ice.In case

2、 of our own planet: the northern and the southern poles are where the ice caps are located. The Ice Is MeltingBy BAN KI-MOON Published: September 17, 2009 New York Times Two weeks ago, I visited the Arctic. I saw the remains of a glacier that just a few years ago was a majestic(宏伟的宏伟的) mass of ice.

3、It had collapsed. Not slowly melted collapsed. I traveled nine hours by ship from the worlds northernmost settlement to reach the polar ice rim. In just a few years, the same ship may be able to sail unimpeded（畅通无阻的畅通无阻的） all the way to the North Pole. The Arctic could be virtually ice-free by 2030.

4、 I was alarmed by the rapid pace of change there. Worse still, changes in the Arctic are now accelerating global warming. Thawing permafrost is releasing methane, a greenhouse gas 20 times more powerful than carbon dioxide. Melting ice in Greenland threatens to raise sea levels.CAUSES geological cha

5、nges seasonal changes global warminggeological changes The causes for these changes can be explained by Milankovitch Cycles. The cycles proposed by him take into account orbital shapes (eccentricity偏心率), axial tilt轴倾角 (obliquity倾角), axial precession岁差, apsidal precession and orbital inclination倾角. A

6、ll these factors, when combined, affect the conditions on the planet in the long term and it causes ice ages at different times. During an ice age the ice caps increase in size and they retreat when an ice age ends. These changes occur over a period ranging from thousands to millions of years.season

7、al changes They are medium-term changes and they occur every year. Every year with the coming of the winter season, the ice caps begin to expand but they melt again with the coming of the summer seasons.Global Warming There are many causes of the melting of the polar ice caps and global warming, som

8、e of which are natural. However, the activities of man are responsible for much of the rapid change that scientists are seeing. Humankind engages in a multitude of activities that have accelerated the process of global warming. Effects of melting Climate Oceans EcosystemsClimate Research carried out

9、 by scientists at NASA(美国国美国国家航空航天局家航空航天局) shows that melting ice caps have an effect on the Earths climate. The polar ice caps that cover the top and bottom of the Earth reflect sunlight into space. When the ice caps recede due to melting, the sunlight is absorbed by the ocean and land instead of b

10、eing reflected back to space. As a result, the planet becomes warmer, more ice melts and the cycle repeats itself. Oceans The NRDC(美国自然资源保护委员会美国自然资源保护委员会 )notes on its website that the melting Arctic ice caps could have an impact on the Earths sea levels. As ice sheets （覆盖物覆盖物）and glaciers（冰川）冰川）mel

11、t, oceans around the world rise. Rising sea levels could have a devastating（毁灭性的）毁灭性的） impact on island nations and cities such as Shanghai that are at or near sea level.Ecosystems The melting polar ice caps have a wide-ranging impact on ecosystems. Migratory（ 迁移的迁移的） animal species that depend on t

12、he Arctic as a place to feed and reproduce（繁殖）（繁殖） are negatively affected by a loss of sea ice. Species that are native to the Arctic, such as polar bears and seals, are particularly hard hit by sea ice reduction.Advices for individuals There are many simple things you can do in your daily life wha

13、t you eat, what you drive, how you build your home that can have an effect on your immediate surrounding . we can do many things to make a difference . Adjust Your Thermostat rmstt n.自动调温器自动调温器, 温度调节装温度调节装置置Use Recycled PaperTake Shorter Showers Install（安装）（安装） a Low-Flow ShowerheadAir Dry Your ClothesBring Cloth Bags to the Market.Extra Effort From Students Recycle Educate Your Parents No Waste at School Meals Plant TreesStart a Club about Environmental Protection. If everybody make a little change and contribution to prevent g