NOTES 20 – The Carbon NOTES 20 – The Carbon Cycle, The Greenhouse Cycle, The Greenhouse

Effect, and Global WarmingEffect, and Global Warming

The carbon cycle continuously moves carbon The carbon cycle continuously moves carbon dioxide (CO2) into and out of the Earth’s dioxide (CO2) into and out of the Earth’s atmosphereatmosphere

The carbon cycle continuously moves carbon The carbon cycle continuously moves carbon dioxide (CO2) into and out of the Earth’s dioxide (CO2) into and out of the Earth’s atmosphereatmosphere

The carbon cycle continuously moves carbon The carbon cycle continuously moves carbon dioxide (CO2) into and out of the Earth’s dioxide (CO2) into and out of the Earth’s atmosphereatmosphere

The carbon cycle continuously moves carbon The carbon cycle continuously moves carbon dioxide (CO2) into and out of the Earth’s dioxide (CO2) into and out of the Earth’s atmosphereatmosphere

The carbon cycle continuously moves carbon The carbon cycle continuously moves carbon dioxide (CO2) into and out of the Earth’s dioxide (CO2) into and out of the Earth’s atmosphereatmosphere

The carbon cycle continuously moves carbon The carbon cycle continuously moves carbon dioxide (CO2) into and out of the Earth’s dioxide (CO2) into and out of the Earth’s atmosphereatmosphere

The carbon cycle continuously moves carbon The carbon cycle continuously moves carbon dioxide (CO2) into and out of the Earth’s dioxide (CO2) into and out of the Earth’s atmosphereatmosphere

1.1. Respiration in the mitochondria of plant Respiration in the mitochondria of plant and animal cells produces COand animal cells produces CO22 waste, waste, which is released into the atmospherewhich is released into the atmosphere

The carbon cycle continuously moves carbon The carbon cycle continuously moves carbon dioxide (CO2) into and out of the Earth’s dioxide (CO2) into and out of the Earth’s atmosphereatmosphere

2.2. Photosynthesis in plants (land) and algae Photosynthesis in plants (land) and algae (water) remove CO(water) remove CO22 from the atmosphere from the atmosphere to make glucose during photosynthesis to make glucose during photosynthesis

The carbon cycle continuously moves carbon The carbon cycle continuously moves carbon dioxide (CO2) into and out of the Earth’s dioxide (CO2) into and out of the Earth’s atmosphereatmosphere

2.2. Photosynthesis in plants (land) and algae Photosynthesis in plants (land) and algae (water) remove CO(water) remove CO22 from the atmosphere from the atmosphere to make glucose during photosynthesis to make glucose during photosynthesis

The carbon cycle continuously moves carbon The carbon cycle continuously moves carbon dioxide (CO2) into and out of the Earth’s dioxide (CO2) into and out of the Earth’s atmosphereatmosphere

2.2. Photosynthesis in plants (land) and algae Photosynthesis in plants (land) and algae (water) remove CO(water) remove CO22 from the atmosphere from the atmosphere to make glucose during photosynthesis to make glucose during photosynthesis

The carbon cycle continuously moves carbon The carbon cycle continuously moves carbon dioxide (CO2) into and out of the Earth’s dioxide (CO2) into and out of the Earth’s atmosphereatmosphere

2.2. Photosynthesis in plants (land) and algae Photosynthesis in plants (land) and algae (water) remove CO(water) remove CO22 from the atmosphere from the atmosphere to make glucose during photosynthesis to make glucose during photosynthesis

The carbon cycle continuously moves carbon The carbon cycle continuously moves carbon dioxide (CO2) into and out of the Earth’s dioxide (CO2) into and out of the Earth’s atmosphereatmosphere

2.2. Photosynthesis in plants (land) and algae Photosynthesis in plants (land) and algae (water) remove CO(water) remove CO22 from the atmosphere from the atmosphere to make glucose during photosynthesis to make glucose during photosynthesis

The carbon cycle continuously moves carbon The carbon cycle continuously moves carbon dioxide (CO2) into and out of the Earth’s dioxide (CO2) into and out of the Earth’s atmosphereatmosphere

3.3. Combustion (burning) of wood, coal, oil, Combustion (burning) of wood, coal, oil, and natural gas add extra COand natural gas add extra CO22 to the to the atmosphere atmosphere

The carbon cycle continuously moves carbon The carbon cycle continuously moves carbon dioxide (CO2) into and out of the Earth’s dioxide (CO2) into and out of the Earth’s atmosphereatmosphere

3.3. Combustion (burning) of wood, coal, oil, and Combustion (burning) of wood, coal, oil, and natural gas add extra COnatural gas add extra CO22 to the atmosphere to the atmosphere

The carbon cycle continuously moves carbon The carbon cycle continuously moves carbon dioxide (CO2) into and out of the Earth’s dioxide (CO2) into and out of the Earth’s atmosphereatmosphere

3.3. Combustion (burning) of wood, coal, oil, and Combustion (burning) of wood, coal, oil, and natural gas add extra COnatural gas add extra CO22 to the atmosphere to the atmosphere

Natural CONatural CO22 Cycle Disrupted Cycle Disrupted

On a global scale, the amount of COOn a global scale, the amount of CO22 put into the atmosphere by respiration put into the atmosphere by respiration is equal to the amount of COis equal to the amount of CO22 removed removed by photosynthesis.by photosynthesis.

Humans have changed the carbon Humans have changed the carbon cycle. The burning of wood and fossil cycle. The burning of wood and fossil fuels like coal and oil adds more COfuels like coal and oil adds more CO22 to to the atmosphere. As a result, the COthe atmosphere. As a result, the CO22 level in the atmosphere is increasing.level in the atmosphere is increasing.

Average Monthly COAverage Monthly CO22 1955- 1955-20052005

Is COIs CO22 in the atmosphere good or in the atmosphere good or bad?bad?

It depends on the amountIt depends on the amount Carbon dioxide is a greenhouse gas, Carbon dioxide is a greenhouse gas,

which means that it traps heat close which means that it traps heat close to the Earth’s surface to the Earth’s surface

This makes the Earth warmerThis makes the Earth warmer

Carbon dioxide is a greenhouse gas which means that Carbon dioxide is a greenhouse gas which means that it traps heat close to the Earth’s surface which makes it traps heat close to the Earth’s surface which makes it warmerit warmer

Carbon dioxide is a greenhouse gas which means that Carbon dioxide is a greenhouse gas which means that it traps heat close to the Earth’s surface which makes it traps heat close to the Earth’s surface which makes it warmerit warmer

Carbon dioxide is a greenhouse gas which means that Carbon dioxide is a greenhouse gas which means that it traps heat close to the Earth’s surface which makes it traps heat close to the Earth’s surface which makes it warmerit warmer

Carbon dioxide is a greenhouse gas which means that Carbon dioxide is a greenhouse gas which means that it traps heat close to the Earth’s surface which makes it traps heat close to the Earth’s surface which makes it warmerit warmer

Carbon dioxide is a greenhouse gas which means that Carbon dioxide is a greenhouse gas which means that it traps heat close to the Earth’s surface which makes it traps heat close to the Earth’s surface which makes it warmerit warmer

1.1. Solar radiation (heat) arrives from the Solar radiation (heat) arrives from the sun and enters the Earth’s atmosphere sun and enters the Earth’s atmosphere

Carbon dioxide is a greenhouse gas which means that Carbon dioxide is a greenhouse gas which means that it traps heat close to the Earth’s surface which makes it traps heat close to the Earth’s surface which makes it warmerit warmer

2.2. The solar radiation reaches the Earth’s The solar radiation reaches the Earth’s surface where some is absorbed and some surface where some is absorbed and some is reflectedis reflected

Carbon dioxide is a greenhouse gas which means that Carbon dioxide is a greenhouse gas which means that it traps heat close to the Earth’s surface which makes it traps heat close to the Earth’s surface which makes it warmerit warmer

3.3. The reflected solar radiation goes back into the The reflected solar radiation goes back into the atmosphere. Some escapes into space and atmosphere. Some escapes into space and some is trapped by greenhouse gasses like COsome is trapped by greenhouse gasses like CO22. .

Carbon dioxide is a greenhouse gas which means that Carbon dioxide is a greenhouse gas which means that it traps heat close to the Earth’s surface which makes it traps heat close to the Earth’s surface which makes it warmerit warmer

4.4. The trapped solar radiation warms the Earth. The trapped solar radiation warms the Earth. Normally, this is good. Without the greenhouse Normally, this is good. Without the greenhouse effect, Earth would be too cold to support life. effect, Earth would be too cold to support life.

Too much of a good thing?Too much of a good thing?

More COMore CO22 in the atmosphere means in the atmosphere means more heat is trapped which means more heat is trapped which means the average temperature of the Earth the average temperature of the Earth increases.increases.

I like warm days so why should I be I like warm days so why should I be concerned about an increase in concerned about an increase in average global temperatures?average global temperatures?

Consequences of Global Consequences of Global WarmingWarming

Sea-level rise (coastal Sea-level rise (coastal flooding)flooding)

Drought and Wildfire Drought and Wildfire increaseincrease

Deadly heat wavesDeadly heat waves Spread of disease Spread of disease

(mosquito range (mosquito range expanded)expanded)

More powerful More powerful hurricaneshurricanes

Ecosystem Ecosystem disruption/species die-disruption/species die-offsoffs

Is Global Warming a fact?Is Global Warming a fact?

YesYes The Earth is definitely The Earth is definitely

getting warmer, and is getting warmer, and is expected to continue to expected to continue to do so in the futuredo so in the future

The real debate is The real debate is whether or not humans whether or not humans are contributing to are contributing to global warming, and if global warming, and if so, what should be so, what should be done about itdone about it

Intergovernmental Panel on Intergovernmental Panel on Climate Change (IPCC) Climate Change (IPCC)

ConclusionConclusion The IPCC concludes that most of the The IPCC concludes that most of the

observed temperature increase since the observed temperature increase since the middle of the 20th century was very likely middle of the 20th century was very likely caused by increasing concentrations of caused by increasing concentrations of greenhouse gases which they believe result greenhouse gases which they believe result from human activity such as fossil fuel from human activity such as fossil fuel burning and deforestation. burning and deforestation.

Greater than 90% likelihood that most Greater than 90% likelihood that most warming over the last 50 years has occurred warming over the last 50 years has occurred because of human-caused emissionsbecause of human-caused emissions

But some skeptic scientists But some skeptic scientists believe…believe…

……that the temperature increase has that the temperature increase has not been caused by an increase in not been caused by an increase in greenhouse gases OR…greenhouse gases OR…

……that the increase in greenhouse that the increase in greenhouse gases has not been caused by gases has not been caused by human activityhuman activity

Could it all be part of a larger natural Could it all be part of a larger natural warming cycle?warming cycle?

What should humans do?What should humans do?

Carry on as usual and hope for the Carry on as usual and hope for the best?best?

Stop burning fossil fuels? Stop burning fossil fuels? Figure out ways to adapt to higher Figure out ways to adapt to higher

average global temperatures?average global temperatures?

Concerned?Concerned?

Use less stuff and convince others to Use less stuff and convince others to do the same – “do the same – “You must be the You must be the change you wish to see in the worldchange you wish to see in the world””