energy conservation and environmental protection

8/10/2019 Energy Conservation and Environmental Protection

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Fourth Year Mechanical PowerEnergy Conservation and Environmental Protection

Air Pollution: Global warming



What is “Global Warming !

• Global warming means an increase in the earth’s average temperature. It is causedmainly by an increase in greenhouse gases. Global warming is a global (not local)

problem and is mainly a global climate change

• Global warming is a different problem from ozone depletion. The so-called ozonehole! is caused by the release of chlorofluoro- carbons ("#"s)$ which brea% down theozone layer. "#"s$ are implicated in global warming$ too. &ut their main impact isdestruction of the ozone layer.

What Causes Global Warming!

' ur planet’s atmosphere traps heat much li%e a garden greenhouse does.

' unlight enters the greenhouse (atmosphere) and warms the soil$ plants$ and ocean(earth).

' *bout +, percent of the sun’s energy is reflected bac% into space. &ut the remainder isabsorbed by greenhouse gases! in the atmosphere and earth’s surface$ where it helpswarm the planet.

' The earth radiates heat bac% to the atmosphere$ where it is absorbed by greenhousegases! such as carbon dio ide and methane. This further warms the earth.

' &ut some of the energy is emitted bac% into space. This prevents the planet fromoverheating.



' This greenhouse effect! is a natural phenomenon that ma%es our planet warm enoughto be livable.

' ithout it$ our planet would be /, degrees #ahrenheit colder than it is today.

What Are the Greenhouse Gases!

"##$ total %& Greenhouse Gas emissions 'rom human activity" 01 20.+34ethane1 5,.,3

6itrous o ide1 7.238ydroflourocarbons and others1 5.93

' "arbon dio ide is the ma:or greenhouse gas.

' hile methane is only 5,.,3 of the pie$ it is actually a more (otent greenhouse gasthan carbon dio ide.

' " 0 arises from burning of fossil fuels (oil$ gas$ coal) and by cutting and burning forests.

' 4ethane arises from landfills (/73 of total methane production)$ livestoc% (cattle$ camels$etc;)$ fossil fuel combustion$ rice cultivation$ termites.

8*<= >? 4=@G=# @4*T

Figure $)": variation o' C* + with time 'rom ,le't: the year "--- to the year +---. and'rom ,right: "#$- to "##$.



/s Global Warming 0a((ening!

8ow do we %now IF the climate is changingA

i.e.$ "an human activities cause a change in climate by increasing the concentration of

greenhouse gases in the atmosphereA

#irst$ let’s see how do we measure the earth temperature and " 0 concentrationA

' @ecords of temperatures on land come from weather stations around the world.cientists use the instruments to trac% temperatures$ rainfall and other precipitation$wind speed$ and barometric pressure.

' *ir bubbles inside of ice core samples from Greenland and *ntarctica tell researchersabout the long-term history of the planet’s climate.

' Tree rings are another way to reveal past trends in temperature and periods of droughtand rainfall.

' Tree rings and ice cores show that concentrations of carbon dio ide in the atmospherehave been going up.

' Buring the last two centuries$ humans have used these fossil fuel resources at anincreasing rate. In 599/$ humanity released about 0+ billion tons of carbon dio ide to

the atmosphere every year by burning fossil fuels. The C. . alone released 7.+ billiontons in 599/ from fossil fuel combustion.

' ome developing countries li%e "hina and India have been increasing their use offossil fuels a lot faster than industrialized nations li%e the C. .



What Could 0a((en 1ater!

' =ven if we ta%e steps now to reduce our emissions of greenhouse gases$ the globe couldwarm up at a rate faster than it has in the past 5,$,,, years

' If we spend all our petroleum and natural gas$ plus similar contribution from coal$ we’ll

add another 07, ppm for a total of /0, ppm (0.0 times pre-industrial level)

' " 0 hangs around a good long while$ so even if we stopped producing it today we’d still be in trouble

' e don’t %now e actly what will happen with global warming or what the impacts will be. *nd where or when they will hit hardest. The system is comple $ and the changes arehard to predict.

' &ut scientists have a pretty good general idea of what’s to come. They say that the possible impacts could be far-reaching and could cause serious problems. ome scientists predict that the earth will warm an additional 0-/ degrees # by the year 05,,.

' cientists say that as global warming happens$ we might see more e treme weather events(ice storms$ hurricanes$ floods$ droughts$ and heat waves). *t this point$ scientists cannotsay for sure that the recent increase in e treme weather events are proof of globalwarming.



&o6 What Can We 8o About Global Warming!

' @ead$ learn and teach about global warming

' Cse energy more efficiently

' Bevelop renewable energy technologies to reduce dependence on fossil fuels.

' @ecycling saves the energy reDuired to manufacture new products.

' @educe energy use1 Give your family’s car a day off by riding your bi%e$ ta%ing the bus or wal%ing.

' <lant and preserve treesFthey absorb carbon dio ide.

' Cse 8ydrogen rather than carbon-based fuels.

' =liminate the " 0 produced by saving it under the oceans.

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