Global Warming: Anthropogenic Effects

Systems and Loops A system: a group of independent parts working together as a whole (e.g. human body) Positive Feedback Loop: Part of a systems output is fed back to input and increases effects of interacting parts

Negative Feedback Loops Decrease the effects of interacting parts to maintain equilibrium. To prevent, slow or reverse changes. Keep Homeostatic levels.

Energy Transfer Conduction –Transfer of thermal energy between 2 objects –E.g. metal pot on stove transfers heat from element to water in pot Convection –Transfer of thermal energy by highly energized molecules moving from one place to another. Fluid create currents –E.g. ocean currents, wind currents Radiation –Transfer of thermal energy from the sun to the earth. Electromagnetic radiation can travel through the vacuum of space heating up our planet

Energy Transfer In Oceans Warmer surface water –Heated by radiation –Less dense because warmer water so stays at surface until current takes it N then the air cools it and it sinks (convection) –Moves quickly at surface Cold dense deep water –Moves slowly at bottom of ocean –Pushes warm water our of the way as it sinks –More salty and dense

Ocean currents: Conveyor belts of energy

Cycles of weather El Nino –Heavy rains –Warmer than normal –Warm air brought by Jet streams across the Pacific La Nina –Dry, drought –Cooler than normal –Warm air & cool moisture pushed away from North America Periodic warming & cooling of a huge mass of sea water. Impacts weather in N. America.

El Nino & La Nina

Green House Gases 90% of atmosphere made of N2 and O2. They don’t absorb infrared radiation Water 1-4% CO % Water Vapour –Most abundant greenhouse gas –Not increasing in amount. Humans don’t release more of it

CO2 and Methane Carbon Dioxide –Main source: Animal respiration –Main human source  combustion of fossil fuels and fires –Main sink is plants and photosynthesis –**Deforestation** removes sink factors Methane –Main source  bacteria that breakdown waste matter –Main source  bogs and swamp lands- increase in decomposing matter –Sink  can be collected & used as a fuel –Sink  start eating Kangaroo instead of cow.

Anthropogenic Effects Anthropogenic Greenhouse Effect –Since 1750 humans have increase CO2 levels mostly from burning fossil fuels –Deforestation & Agriculture –Industrial activities –Methane has increase 1045 ppb –CO2 has increase 104 ppb