Learning objectives Success criteria

Where does carbon enter the living component of the ecosystem?

Where does carbon enter the non-living component of the ecosystem?

What role is played by saprobiotic organisms in the carbon cycle?

What is the greenhouse effect?

Be able to construct a flow diagram to represent the cycling of carbon through the environment.

Develop an understanding of the greenhouse effect and the importance of respiration, photosynthesis and human activity in giving rise to short-term fluctuation and long-term change in global carbon dioxide concentration

Nutrients are constantly recycled through the carbon cycle and the nitrogen cycle.

What happens to nutrients?

microbial decomposition of dead organisms and

waste

nutrients in the soil

and atmospher

e

energy and biomass

energy and biomass

Producers

Decomposers

Consumers

Why is carbon important?Proteins, fats and sugar all contain carbon. Life without carbon would be very different and might be impossible.

Carbon is present in the atmosphere as carbon dioxide (0.04%).

Plants use carbon dioxide duringphotosynthesis to produce sugars. The carbonis then transferred to animals along food chains.

Variations in CO2 levels

CO2 levels are greater at night. Why?No photosynthesis with out light.

CO2 levels on a warm summers day are lower than on a winters day. Why?Rate of photosynthesis increased by temperature.

Carbon cyclingDecomposers – (saprobiotic

organisms) secrete enzymes to break down complex molecules so they can be absorbed by diffusion. They release the carbon as CO2 during respiration.

If decay is prevented the organism may become fossilised in to coal, oil or peat.

Carbon cyclingShells and bones of aquatic organisms

can sink to the bottom of the oceans and form carbon containing sedimentary rocks such as chalk and limestone.

This carbon returns to the atmosphere as CO2 as the rocks are weathered.

• The oceans contain a massive reserve of CO2 which helps to keep the levels of atmospheric CO2 more or less constant.

So you think you know it all!

Draw the carbon cycle without referring to your

books

Increases in global CO2 levelsIn a totally natural situation the carbon cycle

would keep levels of CO2 in the atmosphere more or less the same.

Over the past few hundred years however the CO2 in the atmosphere have increased. Why?

Combustion of fossil fuels

Deforestation

year

0

400

20001960 1980

300

200

100

CO

2 co

nc.

(p

pm

)

What is climate change?

What could be causing this and should we be concerned?

Scientists have predicted that the climate could increase by up to 6°C in the next 150 years.

Climate change is a natural phenomenon and normally takes place over several centuries.

The term ‘climate change’ is being used now to refer to the current climate. This is because recent scientific records show that the global climate seems to be warming up more rapidly than usual.

The average global temperature has increased by 0.6°C in 140 years.

The ten hottest years for the last 100 years have occurred since 1990.

How is the Earth warmed?

Having some greenhouse gases is a good thing. If it wasn’t for these gases, Earth would be too cold to live on!

Climate is affected by the conditions and components of the atmosphere.

Sunlight passes through the Earth’s atmosphere and the Earth gives out infrared radiation. Certain gases trap some of this radiation in the atmosphere, which keeps the Earth warm. This is called the greenhouse effect.

The Earth’s atmosphere acts like the glass in a greenhouse and is needed to keep the planet warm enough for life to exist.

However, too much of a good thing can be bad.

Greenhouse gases

What is global warming? The term ‘global warming’ is often used in connection with climate change, but what does it mean?

Global warming refers to the increase in the Earth’s temperature due to the greenhouse effect, which can cause changes in climate.

However, the term ‘global warming is now being used to refer to the warming predicted to occur as a result of increased emissions of greenhouse gases and other human activities. This enhanced greenhouse effect may lead to significant climate change.

Remember, global warming and climate change are not the same thing and should not be used interchangeably.

Global warmingClimate change - the causes

Learning objectives Success criteria

Where does carbon enter the living component of the ecosystem?

Where does carbon enter the non-living component of the ecosystem?

What role is played by saprobiotic organisms in the carbon cycle?

What is the greenhouse effect?

Be able to construct a flow diagram to represent the cycling of carbon through the environment.

Develop an understanding of the greenhouse effect and the importance of respiration, photosynthesis and human activity in giving rise to short-term fluctuation and long-term change in global carbon dioxide concentration