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Climate change and global warming Aiming Wu Department of Earth and Ocean Sciences University of British Columbia Vancouver, BC, Canada December 2004
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What is climate and climate change? What is global warming and its effects? Why the earth is getting warmer? What climate will be in the future? What shall we do to protect our Earth? Outline
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What is climate ?
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Weather sunnycloudyrainysnowy fogyrain or snow snow (daytime) snow (overnight)
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Weather: what is happening outdoors in a given place at a given time. Weather changes from minute to minute, and place to place. Temperature Precipitation Wind Humidity Visibility How to describe weather?Weather forecast TV, radio newspaper (cold, cool, warm, hot) (rainy, snowy, sunny) (light, strong) (dry or wet) (fogy, dusty) 2 hours later this evening tomorrow ……
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Climate Weather
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Climate: An average of all weather occurring over a period of time in a given place * Monthly, seasonal (or annual) mean temperature or precipitation (don’t look at the weather on a specific day) * tells us what it's generally or usually like * May talks about 10 millions years ago, 10 years ago, this season, this year, next year or 100 years later …… * Climate also depends on time and place
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Different places have different climate…
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Victoria, Canada summer 21 o C winter 8 o C annual precipitation 1250cm Sahara, Africa Max. summer 58 o C annual precipitation 76mm mild Dry, hot
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Tropical forests Warm & wet Europe Cold In winter
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Climate also changes with time ……
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Temperature precipitation Changes with season ……
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Global warming G * Global mean surface temperatures have increased about 1 o F since the late 1800s * The Earth is getting warmer !
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The warming is GLOBAL !
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Temperature changes 1895-1995 British Columbia (Canada)
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What are the effects of global warming? Good or bad to us ?
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Human Health Extreme hot weather can directly cause death (over 40 o C) [normal human body temperature ?] Several serious diseases only appear in warm areas [virus or bacteria like warm place to live] Warm temperatures can increase air and water pollution
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Severe drought or flood more water evaporates, soil will become drier; desert will expand; lake or river levels will drop or even get dried, flood in some other places
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Sea level rise Seas, oceans expand Antarctic, Greenland ice melt low-lying coastal lands drown (many people lose their homes) large area of farmland be ruined
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Farming Some plants and crop cannot grow under higher temperatures Drought makes plants & crop die (need water) people have no enough food, die because of starvation
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Animal, forest-fire Some animal will die when the temperature changes More and more forest fires
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So, global warming is causing serious problems to our environment and our lives...
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Why is the climate getting warmer?
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Earth Atmosphere Other includes : Argon (Ar, 0.9%) Water vapor (H 2 O) Carbon Dioxide (CO 2, 0.03% ) Ozone (O 3 ), CFCs Methane (CH 4 ) Also called “greenhouse gas”
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How to grow plants in winter? greenhouse (a) Let sunlight come in (b) keep heat from going out
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The greenhouse effect
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Greenhouse gas molecules absorb infrared radiation and emit it again
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Greenhouse gases * let the sun rays come in * absorb infrared radiation and emit it back to the Earth Make the earth warmer
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Atmospheric CO 2 is increased rapidly in the recent 100 years !
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Global warming happened only in the recent 100 years
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So the global warming is mainly caused by the increase of CO 2 in the atmosphere
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Who causes CO 2 increase ? Industrial pollution Forest cut Vehicle pollution Human
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Natural pollutions Volcanic ash (works like the greenhouse gases)
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What is in the future ? It is estimated that CO 2 will double from pre-industrial levels in 50-100 years ……
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Global temperature Sea level By 2050: 0.6-2.5ºC By 2100: 1.4-5.8ºC By 2050: 5-30 cm By 2100: 10-90 cm
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What can we do to protect our Earth ? Read and learn about the environment science Save energy (turn off lights, TV, computer…) Use bike, bus, walk or car pool Plant trees (plants absorb CO2, vapor …) Recycle (papers, cans, plastic bags, bottles) Use solar energy Talking to your family and friends (let them know)
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Summary The global climate is getting warmer since the late 1800s The global warming is making our environment worse and threatening out lives Global warming is mainly caused by human activities (industry, transportations etc) However, everyone can do something to protect our Earth
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The end, thank you. Questions & comments ?
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