To explain the relation between global warming and green house gases

Transcription

1 To explain the relation between global warming and green house gases What is Global warming/ Climate change? Global warming is an increase in the average temperature of our Earth s atmosphere and ocean. During the industrial revolution, western countries started to use machines instead of manpower. The age of Machines has caused overuse of fossil fuel, and then a huge amount of green house gases, especially carbon dioxide. During the past 100 years, our earth averagely rose 0.6 degree Celsius. This slight change has made a critical climate change and has destroyed the ecological system. Is the global warming/ climate change really exit? Recently, a lot of sciencists and voluntarily research groups has visited some places which has extreme weather condition, because these places to be the first to be affected. 1. A lot of show and ice are melted is a good indicator of the evidence fo the global warming. Annual average floating sea ice extent has shrunk 2.7%, with large decreases in summer of 7.4%. 2. Global average sea level rose at an average rate of 1.8 mm per year overe 1961 to 2003 and at average rate at about 3.1 mm per year over 1993 to Indeed, we can alert global warming and climate change not onlt from above two common data, but also from the ocean and the crust of our earth. The total are of northen floating ice become smaller and thinner, the freezing period of lake and river become shorter, glaciers are melted, arctic tundra and permafrost become smaller, soil become warmer and the ice core s line become higher and the raise of the sea level. As we mention about ice core, we can use the bubble into it to learn the weather condition million years ago. By analysising the air composition of this bubble, we can estimate the weather condition, for example, scienctists use the concentartion of the specific oxygen isotopes to estimate the average temperature. Use the thickness of each section of the ice core to estimate the snowfall, it seems to the annual ring of trees. (About 550 billion tons carbon dioxide store in the Arctic tundra and frozen soil)

2

3 Carbon cycle: Is it global warming/climate change really affected our earth and daily life? Is it human activities are strongly related to global warming/climate change? First, we can briefly understand the carbon cycle, carbon dioxide will both absorbed and released by the atmosphere naturally, some processes would be slower( for example, when the dead animals under really high pressure and temperature, the dead animals will change to petroleum, this process called Sedimentation) and some would be faster (for example, respiration and the photosynthesis). Release and absorption of carbon dioxide keeps in equilibrium for a billion of years. Human add something into this carbon cycle, fossil fuel burning which will release a huge amount of carbon dioxide into the atmosphere.

4 Remark: 1. Atmosphere: The mixture of gases around celestial object 2. Hydrosphere: It includes all liquid and frozen surface waters, groundwater held in soil and rock, and atmospheric water vapor. 3. Lithosphere: Primarily limestone, coals, gas, and oil; the outer part of the earth, consisting of the crust and the upper mantle. 4. Biosphere: all life on earth (all living organisms); the part of the Earth s environment where life exists 1. Photosynthesis: The process in green plants by which carbohydrates are synthesized by carbon dioxide and water. (most photosynthesis release oxygen) CO! + 2H! O + photons CH! O + H! O + O! 2. Respiration: Process of taking in air for oxygen and releasing it to dispose of carbon dioxide, produce energy during the gases exchange. C! H!" O! + 6O! 6CO! + 6H! O 3. Sedimentation: Slow burial of plant and animal matter on land and on the ocean floor, which eventually becomes limestone, coal, gas, and oil.

5 What is Fossil Fuel? Fossil fuel is a carbohydrate, combined by the carbon atoms and hydrogen atoms, natural gas, petroleum and coal also a fossil fuel. If we use them as the fuel of the generator, the products are carbon dioxide and water, and that are the examples: CH! + 2O! CO! + H! O 2C! H! + 7O! 4CO! + 6H! O The increase in the carbon dioxide has been the principle factor causing global warming. When a huge amount of carbon dioxide has released into the atmosphere, it will intensify the greenhouse effect and raise the earth s average temperature.

6 Do you know what greenhouse effect is? When our earth received the radiation which comes from the sun (about 343Wm!! ), part of solar energy will penetrate the atmosphere then reach to the ground (about 240Wm!! ) and part of radiation will reflect by the atmosphere (103Wm!! ).Then some energy is absorbed by the earth s surface (168 Wm!! ) and warm the earth s surface. Some reflected electromagnetic radiations will absorbed by the greenhouse gases and reemit in random direction, so this process warm our earth for all living organisms. The frequent human activities, for example, fossil fuel burning and the agriculture release a huge amount of carbon dioxide (one of the greenhouse gases) into the atmosphere, which intensify the greenhouse effect and make the earth become hotter and hotter.

7 The earth received the radiation 343Wm!! which comes from the sun Penetrate the atmosphere 240Wm!! Reflected by the atmosphere 103Wm!! Absorbed by the ground 168Wm!! In addition to release a huge amount of carbon dioxide, human also cut off the trees and use the HFCs gases as refrigerant also will intensify the greenhouse effect of our earth. Deforestation seems equal to release 20% total greenhouse gases of our earth, and you may know that trees can store carbon by using photosynthesis. During the photosynthesis, plants will absorb carbon dioxide and release oxygen into the atmosphere, but human activities make fire, desertification, and insect pest threaten trees. HFCs gases is refrigerant, refrigerator and air conditioner are usually used it, the leakage exist during the maintenance check or the equipment reached the end of the using cycle. The Global Warming Potential of the HFCs gases has thousand times than carbon dioxide, that means the HFCs gases is a relatively strong greenhouse gases. Except carbon dioxide and methane, greenhouse gases include nitrous oxide, ozone, CFC, HFC and water vapor. Global Warming Potential (GWP): It is a measure of how much a given mass greenhouse gas is estimated to global warming. It is a relative scale which compares the gas in question to that of the same mass of carbon dioxide. GWP depends on: 1. Absorption of infrared radiation by a given species. 2. The atmosphere lifetime of the species.

8 Is it only human activities cause global warming? Climate is influenced by a variety of factors, both human induced and natural. The IPCC fourth syntheses report concluded that global warming attributed to human activities is roughly about 90%. Another 10% is related to nature, the energy source of almost all life on Earth comes from the Sun. The sun seems unchanged every day, it seems keep a constant luminosity, it also drives all the weather and climate on the Earth for a small change. The sun s energy output has followed its 11 years cycle of small ups and downs, but without any net change. One period of the Earth s orbit around the sun and its tilt towards and away from the sun is about few thousand years. Sun s core temperature reaches 1500 million K, even the surface temperature also reaches 5800K. Under high pressure and temperature p- p chains sustain the nuclear fusion into the core of the sun. The net effect of p- p chain is that 4 hydrogen atoms fuse together become a helium atom and release a huge amount of energy. The energy produced into the sun s core transfer outward slowly. The surface of the sun call photosphere, even the temperature of it is relatively lower than the sun core, but it s also extremely bright to damage your eye (blind) within few seconds (A well known astronomer Galileo was blinded one of his eyes, because he used a telescope to observe our sun directly.).

9 Not only the Sun s energy output and the self motion of our earth affect our Earth s climate, the volcanic eruption also is a factor which affects the average temperature of our earth. During the volcanic eruption, a huge amount of carbon dioxide and ash has been released to atmosphere. These sulfuric dioxide and ash will reflect the energy coming from the Sun, it cause a short term temperature reduction effect of our Earth. On the other hand, eruption also released carbon dioxide and other greenhouse gases all over the world, which will increase the average temperature of our Earth. The emission of greenhouse gases in human activities is much higher than the emission of greenhouse gases in volcanic eruption. You can observe a strong relation between the trend of carbon dioxide concentration and the average temperature of our Earth.

10 How global warming affect environment? A. Species extinction/collapse of ecosystem 1. Coral reef is extremely sensitive for the sea water, when the temperature of the sea slightly raises, then coral bleaching could occur or total destroy the structure of coral. 2. Ice are melted, which will destroy the polar bear s home and they find their food very difficult. Floating ice also help polar bear in transportation and reproduction. 3. The global warming not only affects animals, but also the plant. Plants cannot have a quick change to get with it, and plants also limit by the dissemination of seed and pollen. For plant, the global warming is too fast. Different kinds of animals or insects are lived in a specific plant, if the plants extinct, then a chain reaction of extinction must occurs.

11 B. Huge amount of ice and snow are melted, ocean water expands as it warms are caused the sea level is rising. The total volume of glaciers on Earth is declining sharply all over the world, billion and billion of people are facing flood, drought and lack of drinking water. If ice sheet, floating ice, Greenland icecap and Antarctica are all melted, the sea level must raise drastically, which will highly affect billion people who live under the sea level and coastal area (about 70% population of the world). Accelerated glacial in the Himalayas will compound already severe ecological problems and lack of the clear drinking water across China, India and Pakistan within 30 years (glacial in the Himalayas will melt 80%). If the sea level raises 1m, inundation of several small- island states occur, for example, Maldives will submerge under the sea. Other coastal city also face same problem, London, Bangkok and New York will submerge under the sea. Farms are destroyed, so the food crisis occurs. When we talk about the melting ice and snow, did you see the ice berg? Do you know how big it is? When we see an ice berg (above the water), but that just is a 10% of the whole ice berg. Water can be in gas, liquid and solid form, and the drinking water is liquid form of H! O. The temperature of liquid water decrease to the freezing point (zero degree Celsius), and different temperature and different state give out different density. Therefore, the solid water (ice) has less density than the liquid water, so that the ice will float on the liquid water. That is why scientists estimate if the major ice sheets of the Earth on Greenland and Antarctica are all melted, the sea level will raise about 60-70m.

12 C. Extremely climate The climate and the weather of our earth become abnormal, which cause the precipitation not evenly distributed all over the world, which cause droughts and floods. These extreme weather events point for large losses in productivity for food. In 2007, the extremely weather events has affected 400 million China people, China lost 43 million ton food and 20 billion. 50% population of the world eats rice, when the night temperature raise one degree Celsius, the product of the rice will decrease 10%. Hot day, rainfall unevenly distributed, insect pest and etc. force the world to face food crisis. In , total rainfall recorded in most area of Hong Kong was 200mm or above, Black Rainstorm Warning Signal was given out by the Hong Kong Observatory. Most serious place is Lantau Island where recorded 500 mm total rainfall. Landslip and flooding appeared everywhere all over the Hong Kong,

13 which affected the business, delayed and canceled of flight and traffic accidents appeared, total lost 500 million Hong Kong dollar today. How to solve global warming? Previously, we mention a lot of global impacts, if the global warming is more serious, we must face the inconceivable consequence of our earth. Everyone has responsibility to save the world, so let us know more about how we can protect our earth in daily life. 1. Decrease the usage of fossil fuel, we have a lot of different type of fuels. For example, solar energy, geothermal energy, wind energy, hydro energy, nuclear energy and biomass energy. Let us briefly describe the application and principle of them: A. Solar energy: You must heart about solar energy, convert the light which come from our sun to heat and electricity. When the solar cell received the sunlight, the semiconducting materials inside the solar cell will convert the light energy to electricity (i.e. DC current). Stronger intensity of the light provided large current, and we can collect the light by using reflection, collect light to boil water and generate electricity. We can generate electricity in the area where does not cover by the electricity network by using solar energy. Greenpeace discover a solar cooling system which can preserve food and for storage important medicine.

14 Concentrating solar power (CSP) focus sunlight to heat up some fluid which spin the turbine, generate electricity directly or storage heat in thermal tank. CSP are classified by their different light collecting methodologies. 1. Linear concentrator system, this type can be divided into 2 subgroups, a. parabolic trough system The parabolic reflectors reflect sunlight to a focus line which contain some fluid, high temperature steam/fluid spin the turbine to generate electricity or transfer these liquid into thermal storage tanks. Finally, the steam/liquid enters into condenser, then flow into the focus line again to complete a cycle. b. linear Fresnel reflector system Flat and slightly curved reflectors concentrate sunlight to the focal plane and heat up the fluid into it, hot steam spin the turbine and generate electricity. Lastly, the hot steam will enters into the steam condenser and convert it into

15 cool liquid/steam. 2. Dish/ Engine system It provide relatively small amounts of electricity by compared with the other CSP technologies. Parabolic concentrator gathers solar energy coming from the sun, these light concentrate at the power conversion unit and converts the solar energy to electricity. 3. Power Tower system Numerous largest system in these 3 types of concentrating solar power, it has sun tracking mirrors, known as heliostats. They concentrate sunlight to the receiver at the top of a power tower. Then the fluid (water, nitrate salt) inside

16 the tower is heat up by the solar energy and convert to gas to spin the turbine. B. Geothermal energy: By using a mouth of well, extract the hot water from the heat source. We can use this hot steam to generate electricity directly or transfer the high pressure hot water to the low pressure tank, then the water suddenly convert to steam to generate electricity. The new design model of the electricity station uses the hot water which extract by the hot source to boil another liquid which has lower boiling point. When this material boils, the volume will increase sharply, and then push the turbine to generate electricity.

17 C. Wind energy: Wind turns around the fans, through different types of gears, the wind energy will convert to kinetic energy, then the kinetic energy change to electricity. The cost of using wind energy is relatively low, installation is easy and fast, wind energy can strongly decrease the emission of carbon dioxide. D. Hydro energy/ Wave energy/ Tidal Energy: Hydro energy does not like solar energy and wind energy, hydro energy can work 24 hours continuously, and it is a renewable energy, because the water can be recycle by the water cycle repeatedly. We can use the wave in sea and the river to generate electricity by hydro energy, and faster flow makes large current. E. Biomass/ biofuel energy: By using plants and some living organisms as a fuel, through collect the emitted gases, gasification, burning and digestion of them to produce electricity. We must use biomass energy correctly and carefully, because inappropriate to use biomass energy will affect the environment and release more toxic substance.

18 F. Nuclear energy: By using the unstable element Uranium- 235 as a fuel, when the uranium after extraction and purification, we put them into the reactor and use free neutron to excite the concentrated uranium. Then the uranium will crake itself into 2 or more relatively stable elements, and then release few neutrons and huge amount of energy. The released neutrons will continuous the previous reaction with other uranium atom, which called Chain reaction. Scientist uses this huge amount of energy to boil water and generate electricity. 2. Long times ago, we usually use CFC gas as refrigerant, CFC not only is a strong greenhouse gas, but also can destroy the ozone layer. Therefore, nowadays we use HFC instead of the CFC. It is also a strong greenhouse gas, but HFC does not harm for the ozone layer. Actually, HFC is a compound of chlorine, bromine, carbon and hydrogen, but it does not have any fluorine, so HFC does not destroy the ozone layer anymore. In addition, the heat absorption ability is really good, to reduce this strong greenhouse gas. We can use the different freezing technology, such as, use the carbon dioxide or ammonia, and these techniques are both cost effective. For this reason, we can choose HFC free electronic equipment. Second, when discard old electronic equipment which contain HFC refrigerant, we may seek a professional disposal company to handle these electronic equipment (e.g. refrigerator) 3. 在日常生活中我們也可以減少排放溫室氣體的 少買不必要的衣服 減少住宿賓館時的床單換洗次數 採用節能方式洗衣 一件不必要的衣服减排二氧化碳 6.4 千克少換洗一次床單 被罩可減排二氧化碳 50 克每月用手洗代替一次機洗每年可減排二氧化碳 3.6 千克 少用 1 千克洗衣粉減排二氧化碳 0.72 千克 節能洗衣機減排二氧化碳 9.4 千

19 克 減少糧食浪費 少浪費 0.5 千克水稻減排二氧化碳 0.47 千克 減少畜產品浪費 少浪費 0.5 千克豬肉減排二氧化碳 0.7 千克 飲酒適量 每月少喝 1 瓶啤酒 1 年可減排二氧化碳 0.6 千克, 少喝 0.5 千克白酒 減排二氧化碳 1 千克 減少吸煙 少抽 1 支煙每年可減排二氧化碳 0.37 千克 節能裝修 減少 1 千克裝修用鋁材減排二氧化碳 24.7 千克, 減少 1 千克裝修用鋼 材可節能減排二氧化碳 1.9 千克, 少使用 0.1 立方米裝修用的木材可 排二氧化碳 64.3 千克, 節約 1 平方米的建築陶瓷可減排二氧化碳 15.4 千克 農村住宅使用節能磚 使用節能磚建 1 座農村住宅可減排二氧化碳 14.8 噸 合理使用空調 如果每台空調設置由 26 度上調到 27 度每年可減排二氧化碳 21 千克, 一台節能空調比普通空調每小時少耗電 0.24 度可減排二氧化碳 23 千克, 出門前 3 分鐘關空調一年可減排二氧化碳 4.8 千克 合理使用電風扇 使用中 低檔轉速一年可二氧化碳 2.3 千克 合理採暖 通過調整供暖時間 強度一年可減排二氧化碳 837 千克 農村住宅使用太陽能供暖 一座農村住宅使用被動式太陽能供暖一年減排二氧化碳 2.1 噸 採用節能的家庭照明方式 以高品質節能燈代替白熾燈 1 年可減排二氧化碳 68.6 千克, 養成在 家隨手關燈的好習慣每年可減排二氧化碳 4.7 千克 採用節能的公共照明方式 商場 會議中心等公共場所白天全部採用自然光照明相應減排二氧 化碳 787 萬噸, 我國每年有 10% 的傳統光源被半導體燈代替相應減排 二氧化碳 864 萬噸 每月少開一天車 每月少開一天車每年可減排二氧化碳 98 千克 以節能方式出行 200 公里 騎自行車或步行代替駕車出行 200 公里可減排二氧化碳 36.8 千克 選購小排量汽車 排氣量為 1.3 升的車與 2.0 升的車相比每年可減排二氧化碳 647 千克 選購混合動力汽車 混合動力車可省油 30% 以上每年可減排二氧化碳 832 千克 科學用車, 注意保養 通過及時更換空氣濾清器 保持合適胎壓 及時熄火等措施一年可 排二氧化碳 400 千克 用布袋取代塑膠袋 少生產 1 個塑膠袋只能節能約標準煤可減排二氧化碳 0.1 克 減少一次性筷子使用 全國減少 10% 的一次性筷子使用量每年可減少二氧化碳排放約 10.3 萬噸 儘量少用電梯 通過較低樓層改走樓梯 多台電梯在休息時間只部分開啟等行動每 年可減排二氧化碳 4.8 噸 使用冰箱注意節能 1 台節能冰箱比普通冰箱每年可減少二氧化碳排放 100 千克, 每天 減少 3 分鐘的冰箱開啟時間 1 年可減少二氧化碳排放 177 千克 合理使用電腦 印表機 不用電腦時以待機代替螢幕保護裝置每年可相應減排二氧化碳 1.4 千克, 合理使用電視機 液晶螢幕與傳統 CRT 螢幕相比, 大約節能 50% 減排二氧化碳 19.2 千

20 克, 調低電腦螢幕亮度每年可減排二氧化碳 14.6 千克, 每天少開半小時電視每年減排二氧化碳 19.2 千克, 將電視螢幕設置為中等亮度每年的減排二氧化碳 5.3 千克適時將電器斷電在飲水機閒置時關掉電源一年可減排二氧化碳 351 千克, 電視機 洗衣機 微波爐 空調等家用電器, 在待機狀態下仍在耗每年可減排二氧化碳 197 萬噸 合理用水用淋浴代替盆浴次可減排二氧化碳 8.1 千克, 適當將淋浴溫度調低 1 每年可減排二氧化碳 165 萬噸, 使用感應節水龍頭可比手動水龍頭節水 30% 一年可減排二氧化碳 24.8 千克, 用盆接水洗菜代替直接沖洗一年可減排二氧化碳 0.74 千克用太陽能燒水太陽能熱水器節能 環保, 而且使用壽命長一年可減少二氧化碳排放 308 千克採用節能方式做飯提前淘米並浸泡 10 分鐘, 然後再用電鍋煮每年可減少二氧化碳排放 4.3 千克, 應合理安排抽油煙機的使用時間一年可減少二氧化碳排放 11.7 千克合理利用紙張重複使用教科書一本可減排二氧化碳 0.66 千克, 紙張雙面列印 複印一年可減排二氧化碳 16.4 萬噸, 如果將全國 5% 的出版圖書 期刊 報紙用電子書刊代替一年可減排二氧化碳 85.2 萬噸, 用 1 封電子郵件代替 1 封紙質信函, 減排二氧化碳 52.6 克減少使用過度包裝物減少使用 1 千克過度包裝紙一年可減排二氧化碳 3.5 千克合理回收城市生活垃圾廢紙和玻璃有 20% 加以回收利用一年可減排二氧化碳 690 萬噸夜間及時熄滅戶外景觀燈全國的戶外景觀燈在午夜至凌晨時段及時熄滅一年可減排二氧化碳 846 萬噸在農村推廣沼氣建一個 8~10 立方米的農村戶用沼氣池一年可相應減排二氧化碳 1.5 噸積極參加全民植樹 1 棵樹 1 年可吸收二氧化碳 18.3 千克 Conclusion: We do not fully understand the changing climate of our earth, nowadays, scientists debate on the questions in different area, but we sure certain things: First, the average temperature of our earth has been rising more than the natural climatic cycle. Second, this destructive climate change due to frequently human activities. We have responsibility for more frequent extreme events, drought, lack of clear water and etc. The concentration of carbon dioxide in our atmosphere is extremely high due to the accumulative emission between few thousand years of greenhouse gases, which must highly affect our offspring s environment.

21