1. Intro to Climate Change

2. Climate and Weather Weather Climate
Def: The daily result of changes of temperature, pressure and precipitation in our atmosphere.
Varies from place to place
Can only predict about 5 days ahead and with limited accuracy
Weather can fluctuate widely
Climate
Def: The average weather pattern of many years for a location on Earth
May show long term changes and trends if records are kept
The difference is the timescale on which they are measured

3. Climate and Weather are both affected by…
Clouds
Can both trap heat under them and reflect heat back to the sky
Forest Fires
Releases CO2, but if allowed to regrow…
Volcanic Eruptions
Ash circulates and cools Earth
Ex: Mt Tambora 1815, Mt Pinatubo 1991
Human Activities
Fossil Fuels, Livestock etc.

4. Climate Change Factors that Influence Climate Change
1. Fluctuations in solar insolation
2. Changing proportions of gases in the atmosphere
If there are more greenhouse gases, less heat is loss
The system changes, and may destabilize or…
If a tipping point is reached a new equilibrium will be reached.
Dynamic Equilibrium
Long term record show that
average surface temperature is
Increasing although it does fluctuate

5. Global Climate Models Modeling climate change is super complicated
Models have improved greatly in the last 30 years
Current models predict increases ranging from 1.6 to 4.3ºC

6. The Enhanced Greenhouse Effect
The amount of carbon dioxide in the atmosphere is tiny (0.04%)
However it and other GHGs are increasing due to human activities
Most climate scientists believe that this increase is causing an enhanced greenhouse effect that is causing the planet to warm

7. Global Warming Potential (GWP)
The relative measure of how much heat a known mass of GHG traps over a number of years compared to the same mass of carbon dioxide.
The greenhouse effect varies with each type of GHG
Ex: Methane has a GWP of 21! (21 times stronger than CO2)
Ozone is confusing
Ozone in the troposphere is a GHG
In the stratosphere it absorbs UV so acts as a coolant
***Depletion of the ozone layer does not cause global warming***
CFCs are also confusing
Act as greenhouse gases in troposphere
Breakdown ozone in stratosphere
Very small amount in atmosphere, but very high GWP
**Most GHGs are naturally in the atmosphere, but it is their increase due to anthropogenic activities that is the concern**

8. GWP of GHGs