Fis_Ling_ Climate Change 1

8/14/2019 Fis_Ling_ Climate Change 1

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Climate change

Fisika lingkungan

2007

Pfis-fkip untanls


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1. Has the climate changed during the 20th

century?

Yes, many observations indicate that the world'sclimate has changed during the 20th century

The average surface temperature has increased byabout 0.6C (1F).Snow cover and ice extent have decreased.The sea level has risen by 10 to 20 cm (4 to 8").

Some other important changes include precipitation,cloud cover and extreme temperatures.

Some important aspects appear NOT to havechanged, like Antarctic sea-ice extent or extremeevents such as storms, tornadoes, thunder days, orhail events.


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2. What causes this climate change?

Climate has and will always vary for natural reasons.

However, human activities are increasing significantlythe concentrations of some gases in the atmosphere,

such as greenhouse gases (mainly CO2), which tend towarm the earth surface, and anthropogenic aerosol,which mostly tend to cool it.

Most of the warming over the last 50 years is likelyto have been due to man-made activities.


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3. What climate changes are expected for

the future?

global mean temperature should increase bybetween 1.4 and 5.8C (2.5 to 10F).

the Northern Hemisphere cover should decreasefurther, but the Antarctic ice sheet shouldincrease.

the sea level should rise by between 9 and 88cm (3.5" to 35"). The sea level should continuerising for thousands of years after the climatehas been stabilized.

other changes should occur, including anincrease in some extreme weather events.

After 2100, human induced climate change isprojected to persist for many centuries.


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4. What are the likely consequences of

climate change?

Regional changes in climate, particularly increases intemperature, have already affected some physical andbiological systems.

Both natural and human systems are vulnerable to climatechange because of their limited adaptive capacity. Thisvulnerability varies with geographic location, time, and social,economic and environmental conditions.

Some extreme weather events and the damage, hardship, anddeath they cause are projected to increase with globalwarming.

Man will have to adapt to and cope with the climate changeconsequences that are not prevented by mitigation.

Economic losses can be expected, especially in poorestregions; the higher the warming, the greater the losses.

Promoting adaptation, sustainable development and equity can bemutually reinforcing.


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5. How could Climate Change affect us in the

future?

Projected changes in climate are expected to haveboth beneficial and adverse effects on waterresources, agriculture, natural ecosystems andhuman health.

Human populations are expected to face increasingflooding and heat waves but reduced cold spells.

The geographic range for infectious diseases shouldincrease.

The vulnerability of human populations and naturalsystems to climate change differs substantiallyacross regions and across populations withinregions.


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6. How could greenhouse gas emissions be

reduced?

Climate change is a unique, global, long-term problem,involving complex interactions.

There are many technological options for reducing greenhouseemissions, some at low or negative cost.

Forests and agricultural lands provide significant but not

necessarily permanent carbon sinks, which may allow time forother options.

Greenhouse gas reduction programs need to overcome manybarriers. Governments have a wide array of instruments at theirdisposal. With coordinated actions and international regimes,efficiency and equity should improve.

Further research is required to strengthen future assessmentsand to reduce uncertainties.


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7. Are recent extreme weather events due

to global warming?

It is not possible to link any particularevent definitively to global warming.

But as the world warms, more of some

types of extreme events are expected,such as heat waves, heavy precipitation,blizzards and droughts.

For some other events such as extra-tropical storms, there is little agreementbetween current predictive models.


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8. Do man-made greenhouse gases

matter compared to water vapor?

Water vapor is by far the most importantgreenhouse gas. Nevertheless, the man-made increase in other greenhouse gases

such as CO2 is expected to induce someadditional warming in the coming decades.Warmer air contains more water vapor;this in turn amplifies the man-made

warming. Other reactive mechanisms(feedback) could both amplify or reducethis warming.


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9. Can ecosystems adapt to Climate

Change?

Ecosystems have a limited capacity to adapt toclimate change; some might not be able to copeas they had done in earlier periods and areexpected to suffer damages because:

The rate and extent of climate change isexpected to be faster and greater than in the pastand could exceed nature's maximum adaptationspeed;

Human activities and pollution have increased thevulnerability of ecosystems


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10. What is and is not known with

certainty about climate change?

The earth's average surface temperature has increasedby about 0.6 C (1F) during last century, and humanactivities are increasing the levels of greenhouse gaseswhich tends to warm the planet.

How much and how fast temperatures will continue torise remains uncertain, and the exact impacts of climatechange over the 21st century, especially for localregions, remain largely unknown.

However, global warming poses real risks. Because theexact nature and amplitude of these risks remainsuncertain, we have to use our best judgment guided bythe current state of science to determine what the mostappropriate response should be.


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http://www.global-greenhouse-warming.com/wildfires.htmlhttp://www.global-greenhouse-warming.com/aral-sea.htmlhttp://www.global-greenhouse-warming.com/wildfires.htmlhttp://www.global-greenhouse-warming.com/drought.htmlhttp://www.global-greenhouse-warming.com/climate.html

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