1. The statement above can be proved by the following:

• Earth's Recent History; Carbon dioxide levels have skyrocketed, along with other Green House gases, such as, Nitrogen and Methane.  The levels of those gases have risen much higher than what was calculated in previous years.
• Species Extinctions
• Changing World; (How the Earth's conditions differs from how it used to be and how it is now.)
• Paul Crutzen called this new geological period the "Anthropocene" because of its having such an extreme influence Earth.

  2. The Influences on Climate:

• The Sun
• Earth's Orbit & Tilt of Axis
• Geography
• Biosphere

  3. The Climate Before Human Influence:

• We can expel air from thousands of years ago by drilling deep into the ice found in Antarctica.  In comparison, there are much HIGHER levels of gases in the air now.
• Without our presence, the air would be much more pure than it is now.

  4. Ice Ages

Reasons Why they Occur:

• Global Climate & Temperatures
• The volume of Land and Ice
• The Living World (Inhabitants)
• Sea Level & the Area of Coastal Land
• The Concentrations of Some Gases in the Atmosphere

Their Limits

• Although, some areas of the likelihood for Ice Ages to occur is uncontrollable, their is a so-called pacemaker, which is driven by regular changes in the Earth's orbit and the tilt of its axis.
• This changes when Ice Ages occur because the Earth's orbit is what causes the changes of the seasons.
• In other words, seasons effect the patterns in ice ages.

  5. Climate and Weather

• Climate: range of reasonable expectations that are built up or formed from what is usually seen in a specific area.  (What temperatures can be expected to be seen in part of the world.)
• Weather: the temperature of each individual day.
• Climate Change: Shift in the range for an area.
• Energy; formed from the input of the Sun and how it is redistributed and output back to space.  We receive energy from the sun, and once that occurs it results in an output energy once it hits Earth.
• This is important because it effects the amount of water in the air and oceans.
• The climate experiences change if the input energy varies or if the redistribution & output factors change.  When this occurs it is called 'forced behavior.'
• There is also free behavior, which we can NOT control.

  6. Climate Models

• They are mathematical summaries of what we know about the mechanisms of the climate system.  (They are facts.)
• They need to be able to accurately display the main features of modern climate, or they are useless.
• They are very informative because they allow us to observe the changes in recent times geographically.

  7. What Happens When a Forcing Factor is Pushed Outside its Normal Range

• Drastic increase of levels of methane and carbon dioxide in Earth's atmosphere.
• Greenhouse Gases include: Carbon Dioxide, Methane, Nitrous Oxide, & Water Vapor
• They affect the environment because they can absorb much more heat than oxygen & nitrogen.
• Known as "optically-active" gases
• These levels of gases are increased by human activities.

  8. Greenhouse Effect

• If greenhouse gases are put in the air then outgoing radiation decreases, which makes the temperature increase.

Feedbacks

• We receive feedbacks from various places; they can be positive or negative.
• Water-Vapor: Positive, because it causes the atmosphere to become warmer and wetter.
• Cloud-radiation: Negative, because it reflects energy for plants.
• Negative feedbacks are determined by whether or not it reflects more energy.

  9. Based on the last 500 years:

• Patterns occurring in the Global Climate have undeniably been caused by greenhouse effect and human interactions.
• It is obvious that the 20th and 21st centuries are the warmest, based off of records showing the last several centuries.