4.4: Climate change

Teaching time: 3 hours Practical time: 0 hours

Key vocabulary

Prior learning and retrieval practice

Review topic 4.3 carbon cycling

Review topic 4.2 energy flow

What processes are responsible for moving carbon into the atmosphere and oceans? What processes absorb carbon from the atmosphere?

Evaluating claims

Exercise 1: Where do I stand on climate change?

NoS: Assessing claims—assessment of the claims that human activities are producing climate change. (5.2)

A3: Evaluating claims that human activities are not causing climate change.

DP Command term - Evaluate: Make an appraisal by weighing up the strengths and limitations.

Exercise 2: evaluate each of the following sources using the rubric below:

Evaluating claims in natural science

Source 1

Source 2

Sources 3 & 4

A Positive Trajectory for Corals at Little Cayman IslandCoral reefs are damaged by natural disturbances and local and global anthropogenic stresses. As stresses intensify, so do debates about whether reefs will recover after significant damage. True headway in this debate requires documented temporal trajectories for coral assemblages subjected to various combinations of stresses; therefore, we report relevant changes in coral assemblages at Little Cayman Island. Between 1999 and 2012, spatiotemporal patterns in cover, densities of juveniles and size structure of assemblages were documented inside and outside marine protected areas using transects, quadrats and measurements of maximum diameters. Over five years, bleaching and disease caused live cover to decrease from 26% to 14%, with full recovery seven years later. Juvenile densities varied, reaching a maximum in 2010. Both patterns were consistent within and outside protected areas. In addition, dominant coral species persisted within and outside protected areas although their size frequency distributions varied temporally and spatially. The health of the coral assemblage and the similarity of responses across levels of protection suggested that negligible anthropogenic disturbance at the local scale was a key factor underlying the observed resilience.

Global warming slows coral growth in Red SeaIn a pioneering use of computed tomography (CT) scans, scientists at Woods Hole Oceanographic Institution (WHOI) have discovered that carbon dioxide (CO2)-induced global warming is in the process of killing off a major coral species in the Red Sea.

The effects of increased CO2

A1: Threats to coral reefs from increasing concentrations of dissolved carbon dioxide.

Exercise 3: Read some of the following sources and outline the threats to coral reefs from dissolved carbon dioxide in your own notes.

A2: Correlations between global temperatures and carbon dioxide concentrations on Earth.

U6: Global temperatures and climate patterns are influenced by concentrations of greenhouse gases.

Exercise 4: Watch these videos and outline the relationship between global temperatures and carbon dioxide concentrations

The Greenhouse Effect

Essential idea: Concentrations of gases in the atmosphere affect climates experienced at the Earth’s surface.

U1: Carbon dioxide and water vapour are the most significant greenhouse gases.

U2: Other gases including methane and nitrogen oxides have less impact.

U3: The impact of a gas depends on its ability to absorb long wave radiation as well as on its concentration in the atmosphere.

U4: The warmed Earth emits longer wavelength radiation (heat).

U5: Longer wave radiation is absorbed by greenhouse gases that retain the heat in the atmosphere.

Guidance:

Carbon dioxide, methane and water vapour should be included in discussions.
The harmful consequences of ozone depletion do not need to be discussed and it should be made clear that ozone depletion is not the cause of the enhanced greenhouse effect.

Exercise 5: Run the simulation on the greenhouse effect. Using this and the understandings above try to draw a diagram of the greenhouse effect.

The Enhanced Greenhouse Effect

U7: There is a correlation between rising atmospheric concentrations of carbon dioxide since the start of the industrial revolution 200 years ago and average global temperatures.

U8: Recent increases in atmospheric carbon dioxide are largely due to increases in the combustion of fossilized organic matter.

Exercise 6: Annotate your diagram from the above exercise and add in information about the enhanced greenhouse effect

Global Warming & Climate Change

Exercise 7: Explain the difference between:

The greenhouse effect
The enhanced greenhouse effect
Global warming
Climate change

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