Climate Change (Edexcel A (SNAB) A Level Biology)

The greenhouse effect is one of the largest influences on present-day climate change.

Name the two principal greenhouse gases.

(1)

(1)

(4)

Climate change is often discussed with negative connotations to humans and to society.

However, there are some possible benefits that could come from the current episode of climate change that we are experiencing in the early 21^st Century. For example, global warming may allow photosynthesis to improve in plants.

Explain how this improvement in photosynthesis might occur.

The table below shows some data about certain towns and cities in the Northern Hemisphere:

These town and cities are marked on the map below:

The Gulf Stream (identified on the map above) is a warm ocean current that flows from the Gulf of Mexico in a north-easterly direction towards the continent of Europe.

Climate change is thought to cause the disappearance of the Gulf Stream at some unspecified time in the future. 

Using the information in the table and the map above, predict and explain the likely change in the climate of Haywards Heath and Valencia if the Gulf Stream were to be compromised.

Predict an evolutionary effect that this weather change may have on the plants and animals of the UK.

The table below shows how the density of water varies with temperature (at constant pressure). 

Calculate the percentage decrease of density of sea water between 4°C and 10°C.

(2)

Explain the implications of the above data for habitats and populations of coastal land.

(3)

Peat forms from layers of partly decomposed plant matter and can be cut for fuel.

The illustration below shows a region of peat bog, some of which has been cut for fuel.

Jonathan Wilkins / Peat cutting via Wikimedia Commons

Explain how a peat bog can give clues about the climate over a historical period of time.

Sphagnum moss (Sphagnum capillifolium, pictured below) is a common plant species found growing on peat bogs like the one pictured in part (b).

Sphagnum moss, when it turns to peat over thousands of years, locks away a large mass of carbon. 

Peat fires can sometimes break out underground and burn for months, even years without being able to be put out.

Explain the climatic impact of underground peat fires. 

(1)

Peat fires occur more frequently when areas of peat bogs are dried out or drained for other uses of the land.

Explain why. 

(1)

Sphagnum moss is a highly absorbent material, and can absorb up to twenty times its mass of water. It has even been used in wound dressings during wartime. 

Explain how this absorbency helps to stabilise ecosystems.

(2)

The graph below shows changes in atmospheric carbon dioxide levels between 1960-2010, recorded at Mauna Loa observatory, Hawaii.

Estimate the increase in average atmospheric carbon dioxide concentration between 1960 and 2000.

Suggest why yearly fluctuations occur in actual atmospheric carbon dioxide concentration, as seen in the graph in part (a) above.

In addition to collecting data on atmospheric carbon dioxide levels, scientists also collect data on average global temperatures. Both sets of data between the years 1000 and 2000 are shown together in the graph below.

Evaluate the claim that rising global temperatures are caused by rising atmospheric carbon dioxide levels.

State what the graph suggests about the impact of human activities on atmospheric carbon dioxide levels and average global temperatures. 

Note that the industrial revolution began in the mid 1800s.

The diagram below illustrates the greenhouse effect.

Explain why a higher proportion of the sun’s radiation reaches Earth’s surface than escapes back into space.

The table below shows the global warming potential (GWP) of some other greenhouse gases in relation to carbon dioxide. 

Methane has more than 80 times the radiation absorbing ability of carbon dioxide.

Given that this is the case, explain the high GWP value for methane shown in the table above.

Other than the burning of fossil fuels, state three sources of atmospheric greenhouse gases.