Intro to Climate Change

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

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.

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

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

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

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**

GWP of GHGs