Chahat

330 views
276 views

Published on

PPT On global warming

0 Comments
0 Likes
Statistics
Notes
  • Be the first to comment

  • Be the first to like this

No Downloads
Views
Total views
330
On SlideShare
0
From Embeds
0
Number of Embeds
1
Actions
Shares
0
Downloads
15
Comments
0
Likes
0
Embeds 0
No embeds

No notes for slide

Chahat

  1. 1. All across the world, in every kind of environment and region known to man, increasinglydangerous weather patterns and devastating storms are abruptly putting an end to thelong-running debate over whether or not climate change is real. Not only is it real, its here,and its effects are giving rise to a frighteningly new global phenomenon: the man-madenatural disaster.
  2. 2. CONTENTSWhat is Global WarmingGreenhouse EffectCauses of global warmingRise in sea levelOzone layer depletionForest cover depletionEffects on ecological system(Humans,Marine Lives)Islands/peninsular danger of beingsubmergedConclusionThank You
  3. 3. Global warming is the rising average temperatureof Earth’s atmosphere and oceans since the late .19th century and its projected continuation. Sincethe early 20th century, Earths average surfacetemperature has increased by about 0.8 °C(1.4 °F), with about two thirds of the increaseoccurring since 1980. Warming of the climatesystem is unequivocal, and scientists are more than90% certain that most of it is caused byincreasing concentrations of greenhouse gasesproduced by human activities such as deforestationand the burning of fossil fuels. These findings arerecognized by the national science academies of all
  4. 4. The greenhouse effect is a process by which thermalradiation from a planetary surface is absorbed by atmosphericgreenhouse gases, and is re-radiated in all directions. Sincepart of this re-radiation is back towards the surface and thelower atmosphere, it results in an elevation of the averagesurface temperature above what it would be in the absence ofthe gases. Earth’s natural greenhouse effect makes life as we know it possible. However, human activities, primarily the burning of fossil fuels and clearing of forests, have intensified the natural greenhouse effect, causing global warming.
  5. 5. POLLUTIONBURNING OF FOSSIL FEULS DEFORESTATION OVERPOPULATION RESOURCE • EXESS VECHICLE USE MISEXPLOITATION
  6. 6. Scientists say that thebarrier insulating thecontinental ice caps ismelting. “The impacts ofwarming temperatures inAntarctica are likely tooccur first in thenorthern sections of thecontinent, wheresummer temperaturesapproach the meltingpoint of water, 32 degreesF (0 degrees C).”
  7. 7. As the ice melts, big chunks ofglaciers will break off andbecome like ice cubes in a bigglass of water. The ice chunks,known as icebergs, create massin the ocean. The icebergsdisplace the water causing theocean level to rise. Some of theshoreline in many places likeFlorida (where the land is at alow altitude) will go under water.
  8. 8. At present, sea levels around theworld are rising. Current sea levelrise potentially impacts humanpopulations (e.g., those living incoastal regions and on islands)andthe natural environment (e.g.,marine ecosystems).Global averagesea level rose at an average rate ofaround 1.7 ± 0.3 mm per year over1950 to 2009 and at a satellite-measured average rate of about 3.3± 0.4 mm per year from 1993 to2009, an increase on earlierestimates. It is unclear whether theincreased rate reflects an increasein the underlying long-term trend.
  9. 9. Ozone depletion describes two distinct butrelated phenomena observed since the late 1970s: asteady decline of about 4% per decade in the totalvolume of ozone in Earth’s stratosphere (the ozonelayer), and a much larger springtime decrease instratospheric ozone over Earths polar regions. Thelatter phenomenon is referred to as the ozonehole. In addition to these well-knownstratospheric phenomena, there are alsospringtime polar tropospheric ozone depletionevents.
  10. 10. CFCs and other contributory substances are referred to asozone-depleting substances (ODS). Since the ozonelayer prevents most harmful UVB wavelengths (280–315 nm) of ultraviolet light (UV light) from passingthrough the Earths atmosphere, observed and projecteddecreases in ozone have generated worldwide concernleading to adoption of the Montreal Protocol that bansthe production of CFCs, halons, and other ozone-depleting chemicals such as carbon tetrachloride andtrichloroethane. It is suspected that a variety ofbiological consequences such as increases in skin cancer,cataracts,[3] damage to plants, and reduction of planktonpopulations in the oceans photic zone may result fromthe increased UV exposure due to ozone depletion.
  11. 11. Deforestation is the removal of a forest or stand of trees where theland is thereafter converted to a nonforest use. Examples ofdeforestation include conversion of forestland to farms, ranches, orurban use.The term deforestation is often misused to describe any activitywhere all trees in an area are removed. However in temperateclimates, the removal of all trees in conformance with sustainableforestry practices—is correctly described as regeneration harvest. Intemperate mesic climates, natural regeneration of forest standsoften will not occur in the absence of disturbance, whether naturalor anthropogenic. Furthermore, biodiversity after regenerationharvest often mimics that found after natural disturbance, includingbiodiversity .
  12. 12. Global warming is caused by the emission of greenhouse gases . 72%of the totally emitted greenhouse gases is carbon dioxide (CO2).Therefore CO2 emissions are the most important cause of globalwarming .CO2 is created by burning fossil fuels like e.g. oil, natural gas, diesel.The emissions of CO2 have been dramatically increased within thelast 50 years and are still increasing (CO2 emissions by country).Carbon dioxide remains in the atmosphere for 80 to 200 years.According to recent investigations, unimaginable catastrophicchanges in the environment are expected to take place if the globaltemperatures increase by more than 2° C (3.6° F). A warming of 2° C(3.6° F) corresponds to a carbon dioxide (CO2) concentration ofabout 450 ppm (parts per million) in the atmosphere.The current (year 2007) concentration of CO2 is at about 380 ppmand it is currently increased by 2 to 3 ppm each year.
  13. 13. The world-wide emissions of CO2 for the year 2006 wasabout 28 billion tonnes. What would happen if we frozethe world-wide emissions of carbon dioxide to thecurrent level? Could global warming be mitigated? Forthis purpose, we simulate a constant emission of 30billion tonnes of carbon dioxide per year.The blue curve again shows the effect on the averagetemperature increase. The increase is less steep than inthe example above, but the red zone with temperatureincreases of more than 2 C is still reached. Devastatingeffects on our environment can be expected to startaround the year 2075.
  14. 14.  “Penguin population decline. Adeliepenguin populations have shrunk by 33 percent during the past 25 years in response to declines in their winter sea ice habitat.”
  15. 15. “Coral reef bleaching, the whitening of diverseinvertebrate taxa, results from the loss ofsymbiotic zooxantheallae and/or a reduction inphotosynthetic pigment concentrations inzooxanthellae residing within scleractinian corals.Coral reef bleaching is caused by variousanthropogenic and natural variations in the reefenvironment including sea temperature, solarirradiance, sedimentation, xenobiotics, subaerialexposure, inorganic nutrients, freshwaterdilution, and epizootics. Coral bleaching eventshave been increasing in both frequency andextent worldwide in the past 20 years. Globalclimate change may play a role in the increase incoral bleaching events, and could cause thedestruction of major reef tracts and the extinctionof many coral species.”
  16. 16. Global warming is not something whose effects will befelt centuries later, it is already affecting our lives. Therecent scorching weather is not purely an act of nature.Neither is the increasingly volatile weather that iswreaking havoc in certain parts of the globe. Humans arecausing global warming and we are suffering as a result,and the consequences will only get heavier.The increased temperatures are not only meltingicebergs and glaciers, it is also causing animals to migrateto different areas or die, upsetting ecosystems, and it isalso changing precipitation patterns.
  17. 17. Melting of polar ice caps and flooding The effects of global warming are strongest at the poles. Ice all over the world is melting. This includes the ice on mountain glaciers, Arctic sea ice and ice sheets covering West Antarctica and Greenland. The melting ice increases the sea level and this causes flooding of low-lying areas. When snow and ice melt, their ability to reflect sunlight is lost, escalating global warming even further.
  18. 18. Irregular weather patterns have an effect on humans. Rain is notonly an inconvenience for humans, but storms damage humanproperty. The increase in heat will increase evaporation which is whythere will be more rain. Animals and plants cannot easily adapt toincreased rainfall or snowfall and many animals migrate to otherareas. Plants can die as a result and this can cause an ecosystem tocollapse as plants are the main source of food in an ecosystem.
  19. 19. Changes in Food ProductionThe world has had a food crisis and globalwarming may have been to blame for it. At themoment global warming does not have muchof an impact on this, but in the future, therewill be impacts.As temperatures around the world willincrease, plants will find it harder to cope andthey will die. Some of these plants are used byhumans for food and so a food shortage mayoccur. Plants create food for themselvesthrough a process called photosynthesis. Theenzymes that are needed for photosynthesis diewhen exposed to high temperatures. Pests mayalso migrate to new areas and destroy the cropsthere. Pests may migrate from tropicalcountries to temperate countries.
  20. 20. Human HealthRising temperatures have an effect on thehealth of humans and the diseases thatthey are exposed to.Human health will be affected. The worldglimpsed this in 2003 when Europe wasstruck by heat waves and people died.Heat strokes are likely to increase astemperatures get hotter.Diseases such as malaria are likely tospread. Parasites that originate in tropicalregions may migrate to temperate regionsas they become warmer. Mosquitoes arean example and it is predicted thatmalaria will spread around the world. It isalso predicted that asthma will increasearound the world as allergens that causeasthma will become more common.
  21. 21. Rising seas, caused by global warming, have for the firsttime washed an inhabited island off the face of theEarth. The obliteration of Lohachara island, in Indiaspart of the Sundarbans where the Ganges and theBrahmaputra rivers empty into the Bay of Bengal,marks the moment when one of the most apocalypticpredictions of environmentalists and climate scientistshas started coming true.As the seas continue to swell, they will swallow wholeisland nations, from the Maldives to the MarshallIslands, inundate vast areas of countries fromBangladesh to Egypt, and submerge parts of scores ofcoastal cities.
  22. 22. Eight years ago, as exclusively reported in The Independent onSunday, the first uninhabited islands - in the Pacific atoll nationof Kiribati - vanished beneath the waves. The people of low-lyingislands in Vanuatu, also in the Pacific, have been evacuated as aprecaution, but the land still juts above the sea. Thedisappearance of Lohachara, once home to 10,000 people, isunprecedented.It has been officially recorded in a six-year study of theSunderbans by researchers at Calcuttas Jadavpur University. Soremote is the island that the researchers first learned of itssubmergence, and that of an uninhabited neighboring island,Suparibhanga, when they saw they had vanished from satellitepictures.
  23. 23. Two-thirds of nearby populated island Ghoramara has also beenpermanently inundated. Dr Sugata Hazra, director of theuniversitys School of Oceanographic Studies, says "it is only amatter of some years" before it is swallowed up too. Dr Hazra saysthere are now a dozen "vanishing islands" in Indias part of the delta.The areas 400 tigers are also in danger.Until now the Carteret Islands off Papua New Guinea were expectedto be the first populated ones to disappear, in about eight yearstime, but Lohachara has beaten them to the dubious distinctionHuman cost of global warming: Rising seas will soonmake 70,000 people homelessRefugees from the vanished Lohachara island and the disappearingGhoramara island have fled to Sagar, but this island has alreadylost 7,500 acres of land to the sea. In all, a dozen islands, home to70,000 people, are in danger of being submerged by the rising seas.
  24. 24. Global warming is affectingplants, animals, humans andthe earth. We need to learnhow to conserve our use offossil fuels to minimize carbondioxide production. This willslow down the effects of globalwarming. Before its too late……..

×