Feedback Loops

FEEDBACK LOOPS

Change induces change

What happens when you’re hot?What happens when you’re cold?

These are examples of negative feedbackThe change counteracts the situation

Positive feedback Loops

Change induces change

As long as there are more human births than deaths, population will continue to increase.

Snowball Effect

Feedback Loops in Context

Global warming hypothesizes that the average temperature of Earth is increasing. During analysis, scientists have identified possible positive and negative feedback loops to explain atmospheric climate change.

• http://science.howstuffworks.com/global-warming.htm

Radiation and Reflection

The Greenhouse Effect explained

• http://www.youtube.com/watch?v=LFNKfWyGxHw&feature=related

• Cartoon emphasizing the percentages of radiation and re-radiation.

• http://www.youtube.com/watch?v=GBQ8-zEcE9w&feature=related

• Global warming animation made by an ES kid

• Global warming is a significant increase in the Earth's climatic temperature over a relatively short period of time, mainly as a result of the activities of humans.

• In specific terms, an increase of 1 or more Celsius degrees in a period of 100 – 200 years would be considered global warming. Over the course of a single century, an increase of even 0.4 degrees Celsius would be significant.

Positive or Negative?

• The warming of the oceans causes dissolved

CO2 to bubble out into the atmosphere. This

atmospheric CO2 helps to trap heat near the

earth. This trapped heat continues to warm

the ocean.

Positive or Negative?

• Warmer water temperatures cause greater

water evaporation, which increases the

formations of clouds. A lot of water vapor in

the air also traps heat inside the atmosphere.

Positive or Negative?

• The increased cloud cover from example 2

might also act to reflect sunlight back into

space, preventing it from entering our

atmosphere. This might cool the earth.

Positive or Negative?• Sunlight striking the earth is absorbed by dark

colors and reflected by light colors. The polar

ice caps act like huge mirrors, reflecting

sunlight back into space. Warmer water

temperatures are melting these ice caps and

decreasing these big “mirrors,” leaving dark

water behind.

Positive or Negative?

• Warmer temperatures cause greater water

evaporation, which falls to earth as

precipitation. Therefore global warming may

cause increased snow fall in the polar regions,

leading to increased ice formation.

How did you do?

• 1. Positive

• 2. Positive

• 3. Negative

• 4. Positive

• 5. Negative

Contemplate this…• What would Earth look like if there weren't

any greenhouse effect at all?

• It would probably look a lot like Mars. • Mars doesn't have a thick enough atmosphere

to reflect enough heat back to the planet, so it gets very cold there.

Hmmmmm….• Some scientists have suggested that we could

terraform the surface of Mars by sending "factories" that would spew water vapor and carbon dioxide into the air.

• If enough material could be generated, the atmosphere might start to thicken enough to retain more heat and allow plants to live on the surface.

Just like early Earth…• Once plants spread across Mars, they would

start producing oxygen.

• After a few hundred or thousand years, Mars might actually have an environment that humans could simply walk around in

-- all thanks to the greenhouse effect.