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4A LAU SIN YIN 4B CHOW HAU YI 4D LAU YAN YU SHUM KING SUN

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Today, we are going to explain the most ignored but serious global environmental problem Global warming. Environmental problems are becoming more and more serious in the world, and yet, humans are still neglecting its significance. Or, maybe we cant blame humans if we dont know much about what is happening around us.

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Global warming refers to the increase in the average temperature of the Earth and changes in the amount and pattern of precipitation. Global average near-surface atmospheric temperature rose 0.6 0.2 C in the 20th century. The prevailing scientific opinion on climate change is that most of the warming observed over the last 50 years is attributable to human activities.

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Why global warming has become a major environmental issue all over the world? on a year to year,month to month,and day to day scale,a change in air temperature of a few degrees may not be very significant. But an increase in global temperatures is expected to cause other changes, including weather, sea level and ecosystem,increased intensity of extreme weather events,and changes in the amount and pattern of precipitation. Other effects of global warming include changes in agricultural yields, glacier retreat, species extinctions and increases in the ranges of disease vectors.This is why global warming has become a major environmental issue all over the world.

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1000s to 2000s, > Reconstructed temperature change < 1880s to 2000s, Global Temperatures changes

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All of us know the activity thats increasing the speed of Global Warming is called greenhouse effect. But DO YOU KNOW HOW ITS WORK??

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How does Greenhouse effect work? The greenhouse effect is the process by which absorption and emission of infrared radiation by gases in the atmosphere warm a planet 's lower atmosphere and surface.

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The Earth has cycled many years of warming and cooling over the billions of years but its increasing faster than ever and cant be explained with natural processes. Clearly, humans are chief offender. We are accelerating the natural climatological cycles with our human-created emissions of greenhouse gases.

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What have human done? Human activities:Effects: Fossil fuel power plant Release CO 2 Deforestation25% of all CO 2 release entering the atmosphere Buildings(require lots of fuel) Release greenhouse gases rice paddies, bovine flatulence Release methane

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1.Rising sea levels As the earth gets warmer, the snow and ice cover will melt, meltwater would run into the ocean.The thermal expansion of seawater will lead to a rise in sea level. 2.Change in climate -more frequent extreme climate events -precipitation patterns -climate regions 3.Change in world ecosystem -desertification -extinction of species -bleaching of coral

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1.Health risk Climate change will alter the distribution pattern of parasites, bacteria and carriers of infectious diseases.Hotter summers will lead to more cases of heat-related health problems. 2.Coastal flooding Bring disaster to billions of people living in coastal areas and low-lying countries. 3.Agriculture and food supply A warmer climate would lead to a loss of soil moisture because of a higher evaporation rate. 4.Freshwater supply Higher evaporation rate may lead to shortage of freshwater supply.

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A) Signing and ratifying Kyoto Protocol B) Adopting the Bail Roadmap a) Engaging in a large-scale afforestation

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b) Reduce greenhouse gas emissions -replacing fossil fuels with renewable power resources -use cleaner fuels -improving energy efficiency -improving transport systems -recycling waste -raising public awareness through education

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c) Developing in a sustainable way control population growth farm in a sustainable way develop technologies that are friendly develop our cities in a way that the emission of greenhouse gases can be kept as low as possible

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At home: -Take shorter showers -change tungsten light bulbs to fluorescent bulbs -grow more plants -set the air conditioning temperature at 25 or higher -Open windows to get fresh air instead of turning on the air conditional -switch off electrical appliances rather than leave on standby

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Shopping -bring your own bag -run washing machine with full load -buy recyclable products -choose energy-efficient products -reduce the amount of packaging

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Transport and travel -use mass transit systems -take fewer flights -more cycling and walking Others -take stairs instead of elevators -eat less meat -consume locally produced and seasonal food

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a) Different viewpoints of countries -it is unfair as less developed countries were not required to take any responsibility to control their emission -only the more developed countries control their emission will not help ease the problem b) Their countries will be affected -Tight emission control sets in the Kyoto Protocol will hinder the economy -meeting the emission target incurred extra costs

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