Global Systems
- Human Influence on Climate

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Is the Earth Warming?

All indications are that the earth is warming. In 2007 the (IPCC) reported the following evidence for global warming.

  • Increases in global average
  • of snow and ice
  • Rising global

The Enhanced Greenhouse Effect

It is difficult to identify the exact effect of changes caused by humans because

  • The relative we have been keeping records about climate (just over )
  • Trends that drive climate change take much longer than this

The is the increase in greenhouse effect supposedly caused by man.
Scientist believe that if the current rate of CO2 production remains at 2000 levels there will be an increase in global average temperature of 0.1oC

Carbon Dioxide in the Air

It is estimated that humans only produce about in the air. The largest source is natural decay.

The theory is that carbon sinks balance the natural carbon dioxide levels produced. A carbon sink is a place or event that .

Since the Industrial Revolution it is believed the amount of carbon dioxide in the atmosphere has gone from ppm to ppm.


Methane can trap more than more heat than the equivalent mount of carbon dioxide. It is produced from the breakdown of organic matter. Sources are:

  • Stomach of and
  • fields
  • Methane

The amount of methane in the atmosphere is that before the industrial revolution.

Nitrous Oxide

N2O is 200x better at trapping heat than CO2.  It is about than before the industrial revolution. It comes from

  • Some
  • Burning of
  • Use of

Loss of Ice

Some evidence to suggest is not getting as large in the winter. This reduction in ice leads to by:

  • Less heat back into space
  • More to atmosphere from the ocean (more surface of water not covered by ice)
  • Not as much sinking and driving the “

Carbon dioxide absorption

CO2 is absorbed at the of the water.  As water sinks it takes the CO2 with it into the “global conveyer belt”

Shrinking Antarctica

Evidence suggests that the ice mass of Antarctica is changing ( )