global warming演讲我要参加一个英语演讲比赛,话题是global warming,时间两分半.希望能结合我们身边一些常见的现象来谈论这个话题,而不是用一大堆理论数据泛泛而谈.希望高手帮忙,给一点思路或

global warming演讲我要参加一个英语演讲比赛,话题是global warming,时间两分半.希望能结合我们身边一些常见的现象来谈论这个话题,而不是用一大堆理论数据泛泛而谈.希望高手帮忙,给一点思路或
global warming演讲
我要参加一个英语演讲比赛,话题是global warming,时间两分半.希望能结合我们身边一些常见的现象来谈论这个话题,而不是用一大堆理论数据泛泛而谈.希望高手帮忙,给一点思路或者好的句子都行.谢谢!

global warming演讲我要参加一个英语演讲比赛,话题是global warming,时间两分半.希望能结合我们身边一些常见的现象来谈论这个话题,而不是用一大堆理论数据泛泛而谈.希望高手帮忙,给一点思路或
Global warming is an increase in the earth's temperature due to fuels,industry,and agricultural processes caused by human,natural,and other gas emissions.This results in an increased emission of greenhouse gases.Short-wave solar radiation sinks into the Earth's atmosphere and warms its surface; while long wave infrared radiation emitted by earth's surface is absorbed,and then re-emitted by trace gases.
Climate changes occur in our earth's atmosphere due to a buildup of greenhouse gases.Greenhouse gases can occur naturally as well as a result of human activities.Problems can occur when higher concentrations of greenhouse gases are present in our atmosphere because they have enhanced our earth's heat trapping capability.
There are many misconceptions about global warming.Some believe that pollution causes global warming,but the fact is global warming is the result of burning fossil fuels,coal,and oil that release carbon dioxide.Another misconception is nuclear power causes climate change.Nuclear power actually reduces emissions of carbon dioxide when used in place of coal.Some believe that global warming means that it will become warmer all over.The name is misleading because in some places,it will actually become colder.The majority of scientists believe global warming is a process underway and that it is human-induced.
The greenhouse gases are carbon dioxide,methane,and nitrous oxide.These gases occur naturally.The Earth uses those gases to warm its surface.Carbon dioxide is released into the atmosphere when solid waste,fossil fuels,wood,and wood products are burned.Each greenhouse gas absorbs heat differently.If natural gases did not occur,the temperatures would be 91.4 degrees cooler than the current temperatures.These gases trap heat and cause the greenhouse effect,rising global temperatures.Human activities add to the levels of these gasses,causing more problems.The burning of solid waste,fossil fuels,and wood products are major causes.
Automobiles,heat from homes and businesses,and factories are responsible for about 80% of today's carbon dioxide emissions,25% of methane,and 20% of the nitrous oxide emissions.The increase in agriculture,deforestation,landfills,industrial production,and mining contribute a significant share of emissions too.The gases released into the atmosphere are tracked by emission inventories.An emission inventory counts the amount of air pollutants discharged into the atmosphere.These emission inventories are used by many organizations.
Global warming is a danger to a human's health.Its affect on climate can adversely affect humans.Plagues have been attributed to global warming.An increase in temperature can result in a longer life cycle for diseases or the agents spreading them.Living in a warm area makes egg production a quicker process.Global warming will lead to more precipitation,which enables infectious diseases to be more easily contracted and spread.Effects of global warming on human health might not be immediately detected.
Global warming can affect our future ability to obtain food.As climates change,plants and animals will change,leading to a change in the eating patterns of humans.An increase in precipitation is one result of global warming that could have devastating effects.First,the quality of crops would be affected by an increase in precipitation.Second,increasing rain could lead to an increase in soil erosion.
There are ways that you can help prevent global warming.Car pooling,auditing the energy in your home,buying fuel-efficient cars,and reducing the electricity in your home are ways to help prevent global warming.You can also write to your local congress representative or your local newspaper in response to stories,which say global warming,does not exist.Government authorities can help by passing laws to reduce emissions from factories.They can also form a treaty with other countries to legally bind limits on emissions of heat trapping gases.
The future of emissions damage depends on several factors,demographics,economics,technology,policies and institutional developments.Future predictions do not look good for this planet if nothing is done.Without the help of emissions control policies,CO2 levels are projected to be 30 -150% higher in 2100.Our renewable resources will be very limited.With cooperation from citizens and government officials,we can slow the effect of global warming by reducing greenhouse gas emissions.

http://en.wikipedia.com/wiki/Global_warming
http://www.google.com/search?hl=en&source=hp&q=global+warming&btnG=Google+Search