1. Climate Change – Causes and Impacts
7.2

2. Applications and Skills
Discuss the feedback mechanisms that would be associated with a change in mean global temperature
Evaluate contrasting viewpoints on the issue of climate change

3. Climate and Weather
Weather is daily result of changes of temperature, pressure, and precipitation in our atmosphere.
Climate is the average weather pattern over many years for for loaction on Earth.
Climate change is long-term change and has always happened

4. Factors that Affect Climate Change
Can be natural or anthropogenically influenced
Fluctuations in solar insolation affect temperature
Changing proportions of gases in the atmosphere released by organisms
For climate change to occur on a global scale, inputs and outputs have to change
Heat input increases or heat output decreases or both i

5. Tipping Point GHG’s reduce heat loss from the atmosphere
More GHG’s = less heat lost
The system changes in a dynamic equilibrium which may stabilize or reach a new equilibrium if a tipping point is passed

6. Greenhouse Gases and the Greenhouse Effect
Things to consider when reading about climate change:
Role of ozone and CFC’s
Role of water vapor
Whether figures refer to total GHG effects or the enhanced (anthropogenic) greenhouse effect

7. Global Warming Potential: GWP, relative measure of how much heat a known mass of a GHG traps over a number of years compare to the same mass of carbon dioxide.

13. Feedback Mechanisms Associated with Climate Change
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

14. Feedback Mechanisms Associated with Climate Change
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

15. Feedback Mechanisms Associated with Climate Change
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
negative feedback: aerosols → more clouds → reflect more heat → lowers temperatures

16. Feedback Mechanisms Associated with Climate Change
Polar Ice -
positive feedback: ice melts → exposes more dark water → warmer water melts more ice → exposes more water → more melting → repeats