CLIMATE CHANGE: CLIMATE CHANGE: What We Know and What We Know and What We Don't Know What We Don't Know Baased on a Presentation by Daniel L. Albritton, Baased on a Presentation by Daniel L. Albritton, Director of NOAA Aeronomy Laboratory, during early Director of NOAA Aeronomy Laboratory, during early 2001. 2001. QuickTime™ and a TIFF (Uncompressed) decompre are needed to see this pic
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CLIMATE CHANGE: What We Know and What We Don't Know
CLIMATE CHANGE: What We Know and What We Don't Know. Baased on a Presentation by Daniel L. Albritton, Director of NOAA Aeronomy Laboratory, during early 2001. There is a natural Greenhouse Effect. It keeps the earth warmer than it would be otherwise. Our planet’s atmosphere is composed of:. - PowerPoint PPT Presentation
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CLIMATE CLIMATE CHANGE: CHANGE: What We What We
Know and Know and What We Don't KnowWhat We Don't Know
Baased on a Presentation by Daniel L. Albritton, Baased on a Presentation by Daniel L. Albritton,
Director of NOAA Aeronomy Laboratory, during early 2001.Director of NOAA Aeronomy Laboratory, during early 2001.
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There is a natural Greenhouse Effect. There is a natural Greenhouse Effect. It keeps the earth warmer than it would be otherwise.It keeps the earth warmer than it would be otherwise.
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Our planet’s atmosphere is Our planet’s atmosphere is composed of:composed of:
78% Nitrogen78% Nitrogen 20% Oxygen20% Oxygen *2% Water Vapor *2% Water Vapor
It emits It emits infraredinfrared light light (heat)(heat)
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If an object is bathed in If an object is bathed in sunsunlight...light...
Water VaporWater Vapor andand Carbon DioxideCarbon Dioxide have been have been part of our atmosphere for part of our atmosphere for millions of yearsmillions of years..
They cause an They cause an average surface average surface temperature of temperature of about 60about 60ooF.F.
Without them, Without them, the average the average would be about would be about 55ooF.F.
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Greenhouse gases are increasing in the Greenhouse gases are increasing in the atmosphere because of human activities, atmosphere because of human activities,
and they are increasingly trapping more heat.and they are increasingly trapping more heat.
--Carbon DioxideCarbon Dioxide has has
increased by 31% increased by 31% between 1800 between 1800 and 2000, as and 2000, as measured by ice measured by ice cores and air cores and air samplessamples
-Other gases have -Other gases have increased, too:increased, too:
MethaneMethane SulfurSulfur
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What is the main cause of this increase?
There is a collective picture of a warming world, There is a collective picture of a warming world, and human activities have likely contributed.and human activities have likely contributed.
-Global temperatures are up -Global temperatures are up 0.7 - 1.4 0.7 - 1.4 ooF over the past F over the past 100 years100 years
-Which seems to be causing:-Which seems to be causing:
Glacial retreatGlacial retreat
Snow-cover decreaseSnow-cover decrease
Freeze-free periods Freeze-free periods lengthened lengthened
Global temperature rise of Global temperature rise of 2.5 - 10 2.5 - 10 ooF by 2100F by 2100 If so, this would exceed If so, this would exceed
the natural changes over the natural changes over the past 10,000 yearsthe past 10,000 years
Sea level rise of 4 - 35 Sea level rise of 4 - 35 inches by 2100inches by 2100
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We live on a complex planet We live on a complex planet and we have imperfect knowledge; and we have imperfect knowledge;
so, we can’t predict the future very well.so, we can’t predict the future very well.
We can’t predict a small area’s We can’t predict a small area’s changes, but possibly a continent’s changes, but possibly a continent’s changes:changes:
Temperatures may increase Temperatures may increase as much as 40% above average as much as 40% above average
Mid-continent soil may experience Mid-continent soil may experience increased dryingincreased drying
A warmer world may mean A warmer world may mean heavier rainsheavier rains, , with large with large differences betweendifferences between regions regions
It’s much tougher to call if hurricanes It’s much tougher to call if hurricanes will be will be moremore or or lessless frequent frequent
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BOTTOM LINE - THE VAST BOTTOM LINE - THE VAST MAJORITY OF SCIENTISTS AGREE:MAJORITY OF SCIENTISTS AGREE:
The issue is a real oneThe issue is a real one
The first signs of human-The first signs of human-caused climate change caused climate change have likely occurredhave likely occurred
Some degree of further Some degree of further change appears change appears inevitableinevitable
Exactly Exactly wherewhere (regions), (regions), whenwhen (rate of change), (rate of change), how muchhow much (magnitude) (magnitude) is hard to predictis hard to predict
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The EndThe End
*Remember your three Rs! *Remember your three Rs! Reduce, Reuse, Recycle!Reduce, Reuse, Recycle!