Our Planet’s Changing Climate
description
Transcript of Our Planet’s Changing Climate
Our Planet’s Changing Climate
Forcing and Feedbacks
Our Climate Has Changed Throughout History…
GREEN HOUSE EFFECT
Climate Forcing Several Factors Naturally Change
Climate (Climate Forcers)• Tectonic Processes• Strength of the Sun• Orbit Changes
Humans also Impact Climate• Anthropogenic Impacts
Milankovitch Cycles Three properties impact insolation
from the sun: (This is an external forcing)
• 1) ECCENTRICITY (SHAPE)
• 2) OBLIQUITY (TILT)
• 3)PRECESSION (WOBBLE)
ECCENTRICY: ORBIT SHAPE Describes changes
in distance from the sun as the shape of the elipse changes.
Cycles every 100,000 years
OBLIQUITY: TILT OF THE AXIS The earth’s tilt is the
most dramatic influence on seasons because it results in dramatic differences in the amount of solar radiation in each hemisphere throughout the year.
Cycles every 41,000 years
PRECESSION: EARTH’S WOBBLE Due to the
gravitational pull of the sun and moon
Think of a spinning top
Impacts strength of seasons when shape is elliptical
Cycles every 23,000 years
FEEDBACK LOOPS Positive---Amplifies
the Impact
Negative—Regulatory---Controls the Impact
FEEDBACKS: INTERNAL FORCING Feedbacks can be
• positive or negative• Natural or
Anthropogenic
Example of Positive Feedback (Melting of the Permafrost)• Melting Permafrost