SEAI - Climate change - Further Study

Curriculum Link: Section 2. Resource Management and Consumer Studies, Section 2.2.2
Consumer responsibility, Section 4.4. The Energy-Efficient Home

Climate Change - The Big Picture

"Global warming is one of those things, not like an earthquake where there's a big bang and you say "Oh my God, this really has hit us", it creeps up on you. Half a degree temperature difference from one year to the next, a little bit of rise of the ocean, a little bit of melting of the glaciers and then all of a sudden it is too late to do something about it". Arnold Schwarzenegger (Governor of California and Actor).

The use, abuse and demand for energy resources and the subsequent affect on the environment, in particular the atmosphere, are among the greatest challenges facing humanity today. The terms climate change and global warming appear with increasing frequency in news reports to explain a whole range of natural disasters such as floods, droughts and hurricanes. Yet the issues are complex. Until recently, doubts could be expressed regarding the causes of global warming. Now the evidence is so overwhelming that all but a few individuals accept that global warming is the result of human activity.

The term climate change is used to refer to significant climatic differences from the 'average weather'. These changes take the form of rising temperatures, change in rain patterns, increased droughts and sea level variations. Climate change may take place on a regional or global level and the time scale can vary over years, decades, centuries or millennia.

Evidence for long term climate change comes from a variety of sources:

Ice core analysis
Ice cores from glaciers in places such as Greenland and Antarctica which may contain dust, chemicals and gases that have been deposited with snow over hundreds of thousands of years. These layers reveal past climate characteristics. Oxygen isotopes can also be found in the gases in these ice cores and they provide a record of ancient water temperature and therefore ancient climates.

Pollen analysis
This is the study of pollen found in places like bogs and is very useful in indicating changes in vegetation over the last 10,000 years.

Dendrochronology
This is the study of tree rings and has been used to monitor change over the last 4,000 years.

Evidence is also provided from these sources:
Coral growth Surveys of river activities Analysis of river sediments Studies concerning changes in sea level Fossil records Historical records eg. cave art and literature

Causes of Climate Change

The earth's climate may be altered because of natural causes or human activities, as listed below:

Changes in the earth's orbit every 100, 000 to 400, 000 years.
Changes in the tilt of the earth's axis every 41, 000 years.
Changes in the orientation of the earth's axis every 21, 000 years.
Continental drift eg. the North Atlantic Drift could be deflected by the moving continents.
Volcanic emissions: volcanic dust and gases block out insolation and increase the rarth's albedo (ability to reflect insolation.
Sunspot activity every 11 years.
Human activity e.g. burning fossil fuels changes the atmospheric composition, deforestation and agricultural practices such as pastoral farming.

Graph depicting variation in global near surface land temperature

Global Warming Timeline

Global Warming Timeline: Man in the Anthropocene

In the year 2000, Paul Crutzen coined a new term: Anthropocene. A new epoch had begun and one creature defined this new age, man. Man was seen as altering the planet on a geological scale. This age was termed the Anthropocene. Paul Crutzen believes that this age began with the First Industrial Revolution. Download a timeline from 1769 - 2008.pdf (size 27.6 KB).

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