Творческая работа учащегося "Парниковый эффект".

Муниципальное общеобразовательное учреждение «Лицей №4»

Волжского района г. Саратова

Научно-практическая конференция

«Новая эпоха - новый человек»

Тема: «The Green House Effect»

                                         Выполнил: ученик 7 «В» класса

                                         Федотов Никита

                                        Научный руководитель:

                                        Бабушкина Маргарита Игоревна.                                                                                                                                                                            

                                    Саратов, 2010

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                                                  Introduction

The problem of global warming is very important nowadays. We can’t say that we do not notice it or know nothing about it. The earthquakes and other natural disasters… Are they connected in any way with the greenhouse effect? The more information I learnt about this problem the more questions I had. I wrote the list of questions which seemed for me the most interesting and the most important ones and began to look for their answers. In this work I tried to answer 18 questions using the material I had found in the Internet. So let me show you the main ideas of my work and please be the judges of what you see and hear. You are welcome!

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                                              Main Article

1. What is the greenhouse effect?

The Sun's warmth heats the surface of the Earth, which in turn radiates energy back to space. Some of this radiation, which is nearly all in the infrared spectrum, is trapped in the atmosphere by greenhouse gases. For instance, water vapour strongly absorbs radiation with wavelengths between 4 and 7 micrometres, and carbon dioxide (CO2) absorbs radiation with wavelengths between 13 and 19 micrometres.

The trapped  radiation warms the lower atmosphere, or  troposphere. Some heat then finds its way back down to the Earth's surface, making it hotter than it would otherwise be. This is the greenhouse effect.

2. Are water vapour and carbon dioxide all we have to worry about?

No. Other gases can absorb infrared radiation and contribute to greenhouse warming. These include methane, ozone, CFCs (chlorofluorocarbons) and  nitrous oxide (released by fertilizers). Methane is the most important of these. Its atmospheric concentration has more than doubled since pre-industrial times. Methane sources include bacteria in paddy fields, cattle guts and natural gas from landfills and rotting vegetation. Molecule for molecule, other substances is even more potent greenhouse gases. A single molecule of either of the two most common CFCs has the same greenhouse warming effect as 10,000 CO2 molecules.

3. Is the greenhouse effect a thoroughly bad thing?

Not quite. Without it, the planet would not be warm enough to support life as we know it. The problem is that pre-industrial greenhouse gas levels are being boosted by burning fossil fuels. If nothing is done to curb emissions, the amount of CO2 in the atmosphere will probably be more than double pre-industrial levels by the end of this century.

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4. How do we know what pre-industrial greenhouse gas levels were?

The most informative measurements have come from air bubbles trapped in Antarctic ice. These show that, for at least 400,000 years, CO2 levels in the                                                        

atmosphere have closely followed the global temperatures as recorded in ice cores, tree rings and elsewhere.

5. If measuring greenhouse gas levels is so precise, why is there so much confusion and uncertainty over global warming?

There is no easy formula for predicting what CO2 increases will do to global temperatures. While we can calculate that a doubling of atmospheric CO2 will force roughly 1°C of warming, the planet is more complex than that. It could magnify the effect, but it could also conceivably dampen down warming. Global processes such as the formation of ice and clouds, the circulation of the oceans and biological activity all interact to provide feedback effects.

6. What effects are global warming feedbacks likely to have?

One of the easiest to estimate is the "ice-melting" feedback. As the world warms, ice caps will melt, to be replaced by water or land. Ice is very efficient at reflecting solar radiation, whereas water and land are less so. Therefore, the Earth's surface will trap more heat, increasing warming - a positive feedback.

Less clear-cut is the impact of the extra water vapour likely to enter the atmosphere because of higher evaporation rates. This added water vapour itself contributes to the greenhouse effect, another positive feedback. But it may also increase cloud cover, shrouding and cooling the Earth - a negative feedback.

Disputes about how water vapour and clouds will influence global warming are at the heart of disputes between mainstream scientists and the handful of greenhouse skeptics. Most believe that positive feedbacks could amplify the warming effect by between two and five times. But some skeptics believe the feedback effect could be neutral or negative.

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7. Are there scientists out there who do not believe in the greenhouse effect or global warming?                                                          

No, this is a myth. All scientists believe in the greenhouse effect. Without it the planet would be frozen. And all scientists accept that if humans put more greenhouse gases into the atmosphere then it will warm the planet. The only                                                              

disagreement is over precisely how much the warming will be amplified by planetary feedbacks.

However, there is a growing consensus that the average global warming of 0.6°C seen in the twentieth century - and particularly the pronounced warming of the past three decades - is due to the greenhouse effect.

8. Are there other greenhouse gas complications?

Yes. A whole series of other feedbacks will influence the concentration of greenhouse gases in the atmosphere. Not all the CO2 that we put into the atmosphere stays there. Some is absorbed by vegetation and a lot is taken up by the oceans. If CO2 absorption rate changes, then the rate of build-up in the atmosphere will also change, potentially speeding up, or slowing down, global warming.

One way to increase the build-up of CO2 would be to chop down all the tropical forests. Another could be the impact of warming on ocean currents, particularly the global "conveyor belt" that begins in the North Atlantic. This water carries dissolved CO2 with it on a centuries-long journey across the ocean floor.

Most oceanographers believe that as warming takes hold, and ice formation is reduced, these currents - which lock CO2 up in the depths - could slow down or carry less water, meaning that less CO2 is removed from the atmosphere.                                                          

9. Is there any evidence of a speed-up in the accumulation of CO2 in the atmosphere?

Yes. Since the start of the 21st century, the rate of accumulation has accelerated. It is now at twice the 1990s level. Nobody is sure why. It is not because emissions have accelerated. It could be temporary natural variability. Or it could be that the forests and oceans are losing the ability to absorb our pollution. If so, then global warming could shortly gather pace.

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10. This is all very pessimistic. Is it not true that a warmer planet will absorb more carbon dioxide?                                                            

That is correct. Warmer temperatures and the fertilizing effect of CO2 in the air will stimulate faster plant growth, which in turn will soak up some of the CO2. But plants need other things too. They need water, which could be in short supply as greater evaporation will dry out soils, and space, which urbanization is taking up.

11. How do organisms in the oceans affect global warming?

Once dissolved in surface waters, a great amount of CO2 is absorbed by plankton and other marine organisms and turned into organic compounds. Most of this eventually falls to the ocean floor. The strength of this sink for carbon depends on how much life the ocean is producing. It is not clear to what extent global warming will affect the oceans' biological productivity - it could rise or fall.

12. Is there anything else that could shield us from global warming?

Yes, volcanoes. When Mount Pinatubo erupted in 1991, it threw masses of sulphate particles and dust into the stratosphere that partially shielded the Earth from solar energy. Computer models successfully predicted that the debris would temporarily cool the Earth's atmosphere. The models also predicted that as the volcanic debris cleared in 1992 and 1993, average temperatures would swiftly return first to the level of the 1980s, and then, by the mid-1990s, to the higher levels expected with the ongoing build-up of greenhouse gases.                                                          

13. Volcanoes produce cooling sulphate particles, but do we make them, too?

Yes we do. Ironically, burning fossil fuels produces sulphate particles. These particles - which make acid rain - help to shield industrialized countries from global warming's full impact. In some places, such as central Europe and parts of China, they may have even produce a net cooling effect. Dust from soil erosion and desertification can also curb local warming effects.

But even if you are comfortable with the idea of using one form of pollution to protect us from another, there is a problem. Whereas the average CO2 molecule in the atmosphere lasts for about a century, sulphates and their like persist for only a few days. If you turned down the power stations, the world would get much hotter within a few days. So sulphates are not a solution.

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14. How are temperatures predicted to rise over the next few centuries?                                                                

This depends on whether we halt the growing concentration of greenhouse gases in the atmosphere. Some warming is inevitable - there are time lags in the natural systems which store up warming for future decades. CO2 concentrations are currently about 35% above pre-industrial levels, storing up perhaps another degree of warming.

If we can stabilize atmospheric CO2 concentration by the end of this century, below twice pre-industrial levels, we can probably limit warming to under 5 degrees. But because the gas stays in the atmosphere for a century or more, stabilization requires cutting emissions by 70% to 80%. A tall order. However, some models predict temperature rises of 8 to 10 degrees within 200 years if we do not kick the carbon habit.

15. What are some of the most significant effects global warming will have on the human race?

Unusual droughts are causing serious problems for farming in many regions. Whole countries could get swallowed up by this process, triggering poverty and mass migrations. Super-hurricanes could make other places uninhabitable.

As rainfall patterns alter, rivers will dry up in some regions, while others will flood. Rising sea levels will wipe out many islands and flood low-lying areas, from Bangladesh to the US. As ever, the poor will be most vulnerable. At least in the early decades, rich nations may cope, but ultimately even they could be undermined. Human civilizations have developed over the past 10,000 years – since the end of the last ice age-in an era of generally stable climate. We just do not know well we will cope with a radical change to the climatic status quo.                

16. Will there be global warming everywhere?

Maybe not. Climate modelers admit to uncertainties over how it will affect particular regions. This is because much of our weather depends on circulation patterns, which could alter unexpectedly. Crude estimates suggest that coastal regions may become wetter, while continental interiors become drier, causing deserts to expand. Warming will probably be greatest in Polar Regions, mirroring climate changes already seen this century in both the Arctic and Antarctic.

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Local climate could also be altered by changes in ocean circulation. Western Europe is particularly vulnerable. At present, it is kept exceptionally warm in winter by the Gulf Stream, which is part of the ocean conveyor belt mentioned                                                  

above. Take that away and British weather would be more like Canada's frigid Hudson Bay, found at the same latitude.

Ice cores reveal growing evidence of sudden shifts in climate over the past 10,000 years that have occurred within a few decades as a result of "flips" in ocean circulation. But most models suggest that the Gulf Stream will not turn off for at least another century.

17. Are there any cataclysmic events in the offing?

One fear is that the entire West Antarctic and Greenland ice sheets might disappear into the oceans. According to projections by the UK's Hadley Center for Climate Prediction, before the end of the century a warming of at least 3°C would probably trigger the eventual melting of the entire Greenland ice sheet. The glacial collapse would take hundreds of years, but could raise sea levels by 6 metres.

18. So how worried should we be?

How lucky do you feel?                                                      

I asked to comment the topic on the site in the Internet and this is what I have received:                                                                        

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                                   Comments 1 | 2 | 3 | 4 | 5

What have we done and what can we do?

1. Fri Oct 01 18:50:14 BST 2010 by Akamewane Kingsly

We have been preaching climate change not until recently the world has gone through severe disasters, revealing neglect and calling for more concern for action that lectures and political campaigns, yet what have we done, the countries at the head of pollution list are the USA and China. They have still not done anything and are not willing despite the changes both countries witness as a result of climate change. These disasters are not enough prove for climate change? Please these two nations in particular should copy the example of Germany and some other EU nations.

What Have We Done And What Can We Do?

2. Mon Nov 8 07:03:22 GMT 2010 by Gemma Schuch

I agree that we need to take action,  Akamewane. But I also think we need to think about per capita emissions when we're talking about who should be reducing their emissions. To my knowledge the largest per capita emitters are Australia and the USA. China may have large emissions, but per person, their emissions are very small in comparison to many other countries.

What Have We Done And What Can We Do?

3. Wed Nov 10 01:02:30 GMT 2010 by Lynden Worrall

Per-capita emissions are all well and good when it comes to apportioning blame Gemma, but if you are looking to solve the problem you need to target the largest emitters. Whilst all emitters need to share the load, you could turn off the entire country of Australia tomorrow and be making an almost insignificant impact on global emissions. Smaller cuts from the largest emitters will have a much greater impact overall.

What have we done and what we can do?

4. Thu Nov 04 02:25:11 GMT 2010 by Lloyd Jerome

You claim: "If you turned down the power stations, the world would get much hotter within a few days". This is a fascinating statement; on what research do you                                                        

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base it and what, if any, studies have been conducted that would be the basis for this assertion?

I have another question: whilst I suspect, there are few climatologists who would deny that the climate is indeed changing, is it not the case that most of the evidence that has been accumulated about climate change suggests that we really don't know in a true scientific way, what exactly is happening, and how much of the change is anthropogenic?

5. Sun Nov 14 13:31:29 GMT 2010 by David Hodge

With regard to Q5, the IPCC AR4 2007 report states that the global average surface warming following a doubling of carbon dioxide concentrations is likely to be in the range 2 to 4.5°C with a best estimate of about 3°C, and is very unlikely to be less than 1.5°C.

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                                                Conclusion

Now we see how important this problem is. Many scientists from all over the world try to do every possible thing to solve the problem. But they are nothing without people who leave on the Earth and who are responsible for the future of our fragile planet.  The comments of the people from different parts of the world prove it. So it’s up to us to do our best, to find the way out and to save the Earth for ourselves and for the future generations.

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                                                  Literature

Earth Radiation Budget, http://marine.rutgers.edu/mrs/education/class/yuri/erb.html

Businger, Joost Alois; Fleagle, Robert Guthrie (1980). An introduction to atmospheric physics. International geophysics series (2nd ed.). San Diego: Academic. ISBN 0-12-260355-9.

IPCC assessment reports, see http://www.ipcc.ch/

Henderson-Sellers, Ann; McGuffie, Kendal (2005). A climate modelling primer (3rd ed.). New York: Wiley. ISBN 0-470-85750-1. "Greenhouse effect: the effect of the atmosphere in re-reradiating longwave radiation back to the surface of the Earth. It has nothing to do with glasshouses, which trap warm air at the surface."                                                          

Idso, S.B. (1982). Carbon dioxide : friend or foe? : an inquiry into the climatic and agricultural consequences of the rapidly rising CO2 content of Earth's atmosphere. Tempe, AZ: IBR Press. OCLC 63236418. "...the phraseology is somewhat in appropriate, since CO2 does not warm the planet in a manner analogous to the way in which a greenhouse keeps its interior warm".