Greenhouse Effect Greenhouse Effect and Global Warmingand Global Warming

Greenhouses GasesGreenhouses Gases

Greenhouse Gases absorb heat in our Greenhouse Gases absorb heat in our atmosphere. Examples include…atmosphere. Examples include…

Water VaporWater Vapor Carbon DioxideCarbon Dioxide MethaneMethane Nitrogen DioxideNitrogen Dioxide

Earth’s Atmosphere and Greenhouse Effect… A Good Thing!

77% N2, 21% O2, 1% Ar, + trace gases (CO2, CH4, H2O)

Absorbs incoming solar radiation and warms the planet.

Without our atmosphere, the average Earth temperatures would be a cool -17°C!!

Greenhouse effect gives +32°C warming and allows for liquid H2O to exist on the planet

Greenhouse Effect & Global Warming

• The “greenhouse effect” & global warming are not the same thing.

– Global warming refers to a rise in the temperature of the surface of the earth

• An increase in the concentration of

greenhouse gases leads to an increase in the magnitude/intensity of the greenhouse effect. – This results in global warming

Greenhouse Effect

The science of global warming is too The science of global warming is too uncertain to act on.uncertain to act on.

Myth!!Myth!! FACT: There is no debate among FACT: There is no debate among

scientists about the basic facts scientists about the basic facts of global warming.of global warming.

The only debate about global warming is about how much and how fast warming will continue as a result of heat-trapping

emissions.

Global warming and extra CO2 will be Global warming and extra CO2 will be beneficial — they reduce cold-related beneficial — they reduce cold-related deaths and stimulate crop growth.deaths and stimulate crop growth.

Myth!!Myth!!

FACT: Any beneficial effects will be FACT: Any beneficial effects will be far outweighed by damage and far outweighed by damage and disruption.disruption.

While different pockets of the While different pockets of the country have experienced some cold country have experienced some cold winters here and there, the overall winters here and there, the overall trend is warmer winters.trend is warmer winters.

Fact!!Fact!!

Global warming is just part of a Global warming is just part of a natural cycle. The Arctic has warmed natural cycle. The Arctic has warmed up in the past.up in the past.

Myth!!Myth!! FACT: The global warming we are FACT: The global warming we are

experiencing is not natural. People experiencing is not natural. People are causing it.are causing it.

Natural amounts of CO2 have varied from 180 to 300 parts per million, today’s CO2 levels are around 380 parts per

million. That’s 25% more than the highest natural levels over the past 650,000 yrs.

We can adapt to climate change — We can adapt to climate change — civilization has survived droughts and civilization has survived droughts and temperature shifts before.temperature shifts before.

Myth!!Myth!! FACT: Although humans as a whole have FACT: Although humans as a whole have

survived the drought, stretches of warmth survived the drought, stretches of warmth and cold and more, entire societies have and cold and more, entire societies have collapsed from dramatic climatic shifts.collapsed from dramatic climatic shifts.

Even if people find a way to adapt, the wildlife and plants on which we depend may be unable to adapt to rapid climate change.

Accurate weather predictions a few days Accurate weather predictions a few days in advance are hard to come by. in advance are hard to come by.

FACT!!FACT!! Why on earth should we have confidence Why on earth should we have confidence

in climate projections decades from now? in climate projections decades from now? Climate prediction is fundamentally Climate prediction is fundamentally different from weather prediction, just as different from weather prediction, just as climate is different from weather.climate is different from weather.

As the ozone hole shrinks, global As the ozone hole shrinks, global warming will no longer be a problem.warming will no longer be a problem.

Myth!!Myth!!

FACT: Global warming and the FACT: Global warming and the ozone hole are two different ozone hole are two different problems.problems.

The Greenhouse Effect

Electromagnetic Spectrumincoming outgoing