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                               TOPIC 7.2 CLIMATE CHANGE - CAUSES AND IMPACTS

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The current cycle of global warming is changing the rhythms of climate that all living things have come to rely upon. What will we do to slow this warming? How will we cope with the changes we've already set into motion? While we struggle to figure it all out, the face of the Earth as we know it—coasts, forests, farms, and snow-capped mountains—hangs in the balance.

In this unit you will evaluate the role of greenhouse gases, the effects of rising global temperatures and the arguments associated with global warming. This issue involves the international community working together to research and reduce the effects of global warming.


​This unit is a minimum of 5.5 hours.

 

Significant ideas:

  • Climate change has been a normal feature of the Earth's history,. but human activity has contributed to recent changes

  • There has been significant debate about the causes of climate change

  • Climate change causes widespread and significant impacts on a global scale.

 

Big questions:

  • What strengths and weaknesses of the systems approach and the use of models have been revealed through this topic? How does a systems approach help our understanding of climate change.

  • To what extent have the solutions emerging from this topic been directed at preventing environmental impacts, limiting the extent of the environmental impacts, or restoring systems in which environmental impacts have already occurred? Evaluate the success of the Kyoto Protocol in stabilizing global climate change

  • What value systems can you identify at play in the causes and approaches to resolving the issues addressed in this topic? Explain why there are still uncertainties regarding global climate change

  • How does your own value system compare with others you have encountered in the context of issues raised in this topic? Evaluate measures of mitigation and adaption.

  • How are the issues addressed in this topic of relevance to sustainability or sustainable development? Can sustainable development be achieved without a solution to global climate change

  • In what ways might the solutions explored in this topic alter your predictions for the state of human societies and the biosphere some decades from now? Outline the obstacles to tackling global climate change.

  • How does a systems approach help our understanding of climate change?

  • To what extent do we already know the solutions to climate change?

  • How will we find them/why have they not been implemented?

  • Why are some sectors of society in denial of climate change? do you agree with them? Give reasons to support your answer.

  • Examine the links between climate change and sustainability.

  • Is climate change inevitable? Why?

Knowledging and Understanding

7.1.U1 Climate describes how the atmosphere behaves over relatively long periods of time, whereas weather describe the condition in the atmosphere over a short period of time.

  • Explain the difference between climate and weather.​

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Weather is the daily result of changes in temperature, pressure, and precipitation in the atmosphere. 

  • Varies from place to place

  • Can only be predicted about 5 days out

 

Climate is the average weather pattern over a long period of time for a particular location on Earth. 

  • Can show long term trends.

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Difference is TIMESCALE! 

7.2.U2 Weather and climate are affected by oceanic and atmospheric circulatory systems

  • Describe the Great Ocean Conveyor Belt

  • Explain how oceanic and atmospheric circulatory systems affect both climate and weather.​

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​The world’s ocean is crucial to heating the planet. While land areas and the atmosphere absorb some sunlight, the majority of the sun’s radiation is absorbed by the ocean. Particularly in the tropical waters around the equator, the ocean acts a as massive, heat-retaining solar panel. Earth’s atmosphere also plays a part in this process, helping to retain heat that would otherwise quickly radiate into space after sunset.

The ocean doesn't just store solar radiation; it also helps to distribute heat around the globe. When water molecules are heated, they exchange freely with the air in a process called evaporation. Ocean water is constantly evaporating, increasing the temperature and humidity of the surrounding air to form rain and storms that are then carried by trade winds, often vast distances. In fact, almost all rain that falls on land starts off in the ocean. The tropics are particularly rainy because heat absorption, and thus ocean evaporation, is highest in this area.

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Ocean Systems

  • specific heat capacity

  • surface ocean currents

  • Coastal margins


Atmospheric circulatory systems

  • air motion

  • pressure variations

  • general circulation models

 

7.2.U3 Human activities are increasing levels of greenhouse gases (GHGs, such as carbon dioxide, methane and water vapor) in the atmosphere, which leads to

  • an increase in the mean global temperature

  • increased frequency and intensity of extreme weather events

  • the potential for long term changes in climate and weather patters

  • rise in sea level.

​[GHGs are those atmospheric gases that absorb infrared radiation, causing global temperatures to be higher than they would otherwise be.]
[Students should be able to distinguish between the natural and the enhanced greenhouse effect and to identify a variety of

 

human activities that contribute to GHG emissions. Students must understand the concept of tipping points and how it might be applied to climate change.]

  • Outline the major impacts of increasing levels of greenhouse gases, by humans, in the atmosphere.

Water, CO2, methane and chlorofluorocarbons (CFCs) are the main greenhouse gases. Human activities are increasing levels of CO2, methane and CFCs in the atmosphere, which may lead to global warming.

Human contribution

  • Burning of fossil fuel which release carbon dioxide

  • Deforestation affects earth’s ability to absorb carbon dioxide

  • Agriculture increase the methane level

  • Use of fertilizers lead to higher nitrous oxide

The greenhouse effect is a normal and necessary condition for life on Earth. Consider carbon dioxide (CO2) levels in geological times.

Role of greenhouse gases

  • Maintain mean global temperature

  • Normal and necessary condition for life on Earth

  • allow short wavelengths of radiation such as visible light and UV too pass through to the Earth's surface, but they trap the longer wavelengths such as infrared radiation

 

The systems diagram below was produced by the UN’s IPCC and does an excellent job of showing the inputs, outputs, and relationships among human activities, climate change processes, climate characteristics, and threats to human populations and ecosystems. I recommend studying it extensively.

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7.2.U4 The potential impacts of climate change may vary from one location to another and may be perceived as either adverse or beneficial. These impacts may include:

  • changes in water availability

  • distribution of biomes and crop growing areas

  • loss of biodiversity and ecosystem services

  • coastal inundation

  • ocean acidification​

  • damage to human health,

  • Outline the potential impacts of climate change and how they could be perceived as positive or negative

 

Consider the potential effects on the distribution of biomes, global agriculture and human societies. Appreciate that effects might be adverse or beneficial, for example: 

  • biomes shifting

  • change in location of crop growing areas

  • changed weather patterns which can increase drought and cyclones and the possibility of heavier precipitation events in most areas.

  • coastal inundation (due to thermal expansion of the oceans and melting of the polar ice caps) and possibility of water shortage

  • human health (spread of tropical diseases).

  • agriculture may shift towards the poles

  • human health can be affected by the spreading of tropical diseases

  • extinction of species in wild as many could not adapt to sudden climate change

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7.2.U5 Both negative and positive feedback mechanisms are associated with climate change and may involve very long time lags

  •  Discuss the feedback mechanisms that would be associated with a change in mean global temperature

  • Explain how some of the feedback mechanisms can involve time lags.​

 

Feedback mechanisms play a key role in controlling the Earth's atmosphere. Changes to these mechanisms will have an impact on the climate

Positive feedback

  • melting of polar ice lowers albedo

  • increased carbon dioxide released from increased biomass decomposition

  • tropical deforestation increases warming and drying

  • increases forest cover decreases albedo


Negative feedback

  • increased evaporation in low latitudes due to high levels of precipitation

  • increasein carbon dioxide in atmosphere leads to increased plant growth

 

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Any feedback mechanisms associated with global warming may involve very long time lags.
 

7.2.U6 There has been significant debate due to conflicting EVSs surround the issue of climate change.
[A minimum of two different viewpoints should be considered​]

  • Outline the debate surrounding climate change in contest of EVSs.


Sometimes conflicting arguments surround the issue of global warming. Note the complexity of the problem and the uncertainty of global climate models. Be aware of the concept of global dimming due to increased levels of atmospheric pollution.

Why?

  • Greenhouse gases can be produce by natural: volcanic activity; release of methane by animals and peat bogs; sunspot activity

  • Earth’s tilt and variation in orbit around the sun leads to seasonal and regional changes in temperatures

  • Ocean currents can lead to warming or cooling

  • Global dimming: the cooling effects of air pollution


Complexity of the Problem: 

  • On a huge scale: atmosphere, the oceans and the land

  • Not all feedback mechanisms are fully understood

  • Many impact and processes are long-term


Uncertainty of climate models

  • How much is the planet warming

  • Where will the impacts of global warming be felt most acutely

 

You should explore different viewpoints in relation to your own. Consider the different view of 'ecocentric', 'authropocentric' and 'technocentric'.

 

7.2.U7 Global climate models are complex and there is a degree of uncertainty regarding the accuracy of their predictions.

  • Explain how the complexity and degrees of uncertainty affect the accuracy of climate model predictions.​

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​Climate models are mathematical representations of the interactions between the atmosphere, oceans, land surface, ice – and the sun. This is clearly a very complex task, so models are built to estimate trends rather than events. For example, a climate model can tell you it will be cold in winter, but it can’t tell you what the temperature will be on a specific day – that’s weather forecasting. Climate trends are weather, averaged out over time - usually 30 years. Trends are important because they eliminate - or "smooth out" - single events that may be extreme, but quite rare.

  • an issue on a large scale

  • interactions between atmosphere, oceans and land

  • natural as well as antrhopogentic forces

  • not all feedback mechanisms understood

  • long-term impact not known

 

Applications and skills:

7.2.A1 Discuss the feedback mechanisms that would be associated with the change in mean global temperature

Oceans absorb CO2 from the atmosphere as they warm up, they release CO2 back into the atmosphere and absorb less phytoplankton (producers) photosynthesize faster in warm water

  • Positive feedback mechanism: more atmospheric CO2 → warmer temperatures → less CO2 absorbed & more released by oceans → more atmospheric CO2

  • Negative feedback mechanism: warmer oceans → faster photosynthesis by phytoplankton → more CO2 absorbed for photosynthesis → lower atmospheric CO2 → lower temperatures, slowing global warming

 

Clouds -  different cloud types interact with heat differently: 

  • daytime clouds cool the area under them

  •  nighttime clouds trap heat and act as an insulating layer

  •  high thin cirrus clouds trap heat

  •  low thick cumulus and cumulonimbus clouds have a cooling effect 

  • Negative feedback: higher temperature→ more evaporation → more clouds → clouds block & reflect incoming solar radiation → lower temperatures

  • Positive feedback: higher temperatures → more evaporation → more clouds → more heat trapped → high temperatures

 

Pollution - 

  • positive feedback: aerosols → more clouds formed → trap heat → warmer temperatures → more evaporation → more clouds → more heat trapped 

  • positive feedback: black soot (particulates) falls on ice → dark color absorbs more heat → ice melts faster → more dark water/ground exposed → warmer temperatures → more melting → repeats

  • negative feedback: aerosols → more clouds → reflect more heat → lowers temperatures

 

Forests - 

  • positive feedback: forests absorb 

 

Polar Ice - 

  • positive feedback: ice melts → exposes more dark water → warmer water melts more ice → exposes more water → more melting → repeats

•    Tundra - 
•    Atmospheric CO2 - 

 

7.2.A2 Evaluate contrasting viewpoints on the issue of climate change
[A minimum of two different viewpoints should be considered]

  • Viewpoint 1: We can reduce human carbon emissions 90% within the next few decades with current technology, but a lack of political and industrial leadership is preventing us from doing so. (The George Monbiot viewpoint.)

  • Viewpoint 2: Global warming and climate change are already happening as a result of human activities, even though we don’t fully understand the degree of warming or the complete mechanisms by which the changes take place. (The Al Gore and IPCC viewpoint.)​

  • Ecocentric: 

  • Anthropocentric:

  • Technocentric:

 

Classroom Materials
Climate Feedback Loops
Global Warming Reading​
Rising Temps Case Study​
Review Common Misconceptions
Climate and Malaria
​As Rising Heat Bakes U.S. Cities, The Poor Often Feel It Most article
Global Warming and Agriculture article
Climate Change Data Analysis activity
Climate Change Data Analysis graphs
Global Warming PHET simulation
Global Warming and Hurricanes Data Analysis Activity

Case Studies
Effects of global warming: Give specific examples of the impacts of climate change listed below

  • spread of tropical diseases

  • movement of biomes

  • impacts on coastal populations and infrastructure

  • sea levels

  • weather patterns

  • agricultural productivity

 

Useful Links
Greenhouse effect - Sumanis
Factors Affecting Global Climate - Nature
Four ways to look at global carbon footprints - an infographic from National Geographic magazine
Common questions about climate change from the United Nations Environment Program (1997)
The Issue of Global warming - This is the above UNEP site converted to a MS Word document for offline viewing. 
How reliable are CO2 measurements? - Skeptical Science
Review on the Economics of Climate Change - BBC News
Feedback Effects - BBC News
Climate Change Around The World - BBC
UN Framework Convention on Climate Change - UN
Global Warming Effects Simulation - National Geographic
Investigating carbon offsets - Carbon Footprint
Investigating carbon offsets - Environmental Research WEb
Understanding Global Dimming - NOVA
Global Warming - Take Part
Cause and Effect of Global Warming - S-Cool
The Great Global Warming Swindle - wagtv
Topic 6: The issue of global warming, part 1 - NicheScience
Topic 6: The issue of global warming, part 2 - NicheScience
Topic 6: The issue of global warming, part 3 - NicheScience

Click to Run


In The News
Young people are suing governments over climate change - Gold Coast Bulletin, March 2016
Scientists develop CO2 sequestration technique that produces ‘supergreen’ hydrogen fuel -  Maybe a way to fulfill growing energy needs and combat global warming at the same time? from LabManager.com
Massive Antarctic Glacier Uncontrollably Retreating, Study Suggests - LiveScience Jan 2014
Acidic oceans dissolving shells of marine organisms - The Register 26 November 2012
Carbon Trading Causes Increase in Greenhouse Gas Emissions - New York Times 8 August 2012.
Scientists Concerned About Effects of Global Warming on Infectious Diseases - Science Daily, 22 May 2007
Polar Ice Loss Quickens, Raising Seas - BBC Science and Environment News 9 March 2011
Penguin and Krill Populations Decline due to Climate Change - Discovery News 11 April 2011
Global carbon emissions reach record, says IEA - BBC Science and Environment News 30 May 2011.
Species flee warming faster than previously thought - BBC Science and Environment News 20 August 2011
Why the warming climate makes animals smaller - New Scientist 23 September 2011
Marine life shifts as temperatures change - New Scientist 24 September 2011
Global Warming: Runaway temperature increase unlikely - Summit County Voice 25 November 2011
China report spells out “grim” climate change risks - Reuters 17 January 2012
Ocean currents and their role in global climate change - The Register 30 January 2012
Plant study flags dangers of a warming world - NewsDaily Science News 2 May 2012
This is a great article about agroforestry in the Sahel - Scientific American 28 January 2011
Indigenous people have much of the knowledge needed to adapt to climate change - Trust.org 24 April 2012

Check out our data visualization blog.

 

International Mindedness:

  • The impacts of the climate change are global and require coordinated international action.

 

TOK:

  • There has been considerable debate about the causes of climate change-does our interpretation of knowledge from the past allow us to reliably predict the future?


Video Clip

NASA Connect segment explaining the difference between weather and climate. The segment explores what factors determine weather and how climate is affected by the weather.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

In this video Paul Andersen describes both weather and climate. Weather is the day-to-day conditions on the Earth's surface, including temperature, wind, humidity, air pressure, and precipitation. Climate are the long term conditions on the Earth's surface. Both climate and weather are determined by sunlight, water, landforms and life forms

 

 

 

 

 

 

 

 

 

 

 

 

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This multi-part film examines the politicization of climate change over the last several decades

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

​Global warming could do more than just melt polar ice.  It could change our maps, and displace people from cities and tropical islands

 

 

 

 

 

 

 

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With rising temperatures and seas, massive droughts, and changing landscapes, successfully adapting to climate change is increasingly important. For humans, this can mean using technology to find solutions. But for some plants and animals, adapting to these changes involves the most ancient solution of all: evolution

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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A section from Caution, the 2nd movement of  Energy Union. Music by The Creeper and J Dilla. Aims to bring a little clarity as many people still don't accept the reality of manmade climate change. Although no-one fully understands how Earth's climate works, it is may be useful to listen to the solid consensus of reputable scientists and filter out the opposing climate skeptics, many of whom are 'Quacks' with limited credentials and dubious motivations. 

 

 

 

 

 

 

 

 

 

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This short film/ documentary-esque video asks the contemporary ethical question of: "Given the general scientific consensus that anthropogenic (human induced) climate change is real, are we ethically obliged to take action to stop it?"

 

 

 

 

 

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How much are human practices contributing to substantial and irreversible changes to the environment?  What effect are changes to the climate having in different areas of the planet?

 

 

 

 

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Controversial Danish economist Bjørn Lomborg explains why it's important to question orthodox opinion -- even the widespread fear of global warming.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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The biggest problem for the climate change fight isn’t technology – it’s human psychology. Vox takes a look at efforts energy-saving companies are taking to take advantage of human psychology. 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The Great Global Warming Swindle, A great documentary by the BBC that exposes the politics behind this shameful manipulation of the people of the world. Originally broadcasted March 8, 2007 on British Channel 4.

 

 

 

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Why People Don't Believe in Climate Change

 

 

 

 

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Climate Change (7.2-7.3)

An Overview of Climate Change

Symphony of Science- overview of Climate change issues using music
Climate change FAQ- series of articles and ideas
NASA resource reel - links to various affects on the earth
300 Years of Fossil Fuels- a history of the fossil fuel movement

​Movies: 
An Inconvenient Truth 
The Great Global Warming Swindle

The Debate

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Pro
Is Climate Change real?- evidence for Climate Change 
An explanation of the scientific debate-Includes some of the physics and chemistry of the science
"Why the skeptics are wrong"

Con
An Obnoxious Fabrication of Global Warming- interesting counterargument
Sunspots and Climate
​a literature review of An Inconvenient Truth
Roy Spencer, PhD website​

Causes and Impacts (7.2) 

Global Climate Model- what is it?
CO2 and Temperature Data 
Mann's Hockeystick graph ---- Not everyone agrees that the graph is solid

 

Possible Impacts of reaching a tipping point

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