Climate change notes

by jasooooon (student)

FACTORS THAT AFFECT CLIMATE CHANGE

Atmosphere: A layer of gases that surrounds a planet or moon
Weather: Condition of the atmosphere in a specific place at a specific time (describes wind, temp, moisture)
Climate: Characteristic weather patterns within a region averaged over a long period of time (Temp, wind velocity)
Earth has experienced many climate changes in the past

EARTH AND THE SUN

Sun’s energy is the most important factor affecting climate on Earth (winds, rain etc)
The amount of radiation produced by the sun varies and a regular solar cycle (sunspot cycle) occurs every 11 years
When the number of sunspots is high, the Sun emits higher amounts of solar radiation.
Earth rotates tilted (23.5º) on an axis every 24 hrs
the combination of Earth’s annual orbit and its tilted axis produces the seasons

Revolution: the time it takes for an object to orbit another object

CHANGES IN EARTH’S ORBIT

Earth’s orbit, tilt and rotation change in repeating cycles
(1) Eccentricity: every 100 000 years, Earth’s orbit changes from circular to elliptical
Elliptical orbit means more solar energy for Earth which affects length of seasons
(2) Tilt: Earth’s tilt changes every 41000 years by about 2.4º
The greater the tilt, the greater the temperature differences between summer and winter
(3) Wobble: Earth wobbles (precesses) since it is not a perfect sphere
This wobble affects the amount of solar energy hitting ...

CHANGES IN EARTH’S ORBIT

Earth’s orbit, tilt and rotation change in repeating cycles
(1) Eccentricity: every 100 000 years, Earth’s orbit changes from circular to elliptical
Elliptical orbit means more solar energy for Earth which affects length of seasons
(2) Tilt: Earth’s tilt changes every 41000 years by about 2.4º
The greater the tilt, the greater the temperature differences between summer and winter
(3) Wobble: Earth wobbles (precesses) since it is not a perfect sphere
This wobble affects the amount of solar energy hitting the northern and southern hemispheres

EFFECT OF LATITUDE ON CLIMATE & SEASONS

The equator is hotter since the sun’s rays strike the Earth at 90
A ray hitting the Earth as 45 south strikes the Earth at an angle spreading the energy over and area 1.5 times larger
At the poles, rays are spread out even more; each square meter of area receives even less energy

HOW ATMOSPHERE AFFECTS CLIMATE

Atmosphere is made of N2, O2 and H2O; absorbs energy from Sun and traps energy from Earth’s surface
Greenhouse Effect: Warming caused when the atmosphere absorbs thermal energy radiated by the Sun and Earth

WINDS DISPERSE ENERGY IN ATMOSPHERE

Wind: The movement of air from an area of high to low pressure as a result of uneven heating
Transfers thermal energy around the world from warm to cooler areas; affects ocean currents and precipitation patterns

WINDS MOVE OCEAN CURRENTS

Energy from the moving air is transferred to the surface of the water – causing water to move
Oceans absorb energy from the sun; movement of water transfers heat around the Earth’s surface
Prevailing winds: wind that blows in a constant direction around the world

WINDS AFFECT PRECIPITATION

As one air mass rises above another, the rising air cools and water vapor condenses forming precipitation
Jet Streams: high-altitude winds that travel long distances at high speeds – carry warm moist air producing precipitation or dry air causing dry weather

HOW THE HYDROSPHERE AFFECTS CLIMATE

Hydrosphere: Collective mass of water on Earth in liquid, solid and vapor form
Oceans & lakes are a heat reservoirs; buffer temperature changes in the atmosphere (water has a high specific heat capacity)
Specific Heat Capacity: The amount of heat required to raise the temperature of 1g of substance by 1ºC
Ocean temperatures change very slowly
Earth’s Albedo: the fraction of light that is reflected by the surface of Earth back into space
Snow and ice reflect solar radiation (because of their color)
The ocean reflects 7% of solar energy; fresh snow can reflect up to 90% - these differences affect average global temperature

HOW MOVING CONTINENTS AFFECT CLIMATE

Tectonic Plate: Piece of the Earth’s shell that moves around on flowing underlying rock
Earth has 12 major plates; changing distribution of land and water affects air patterns, water circulation and transfer of thermal energy
Volcanic eruptions spew particles in the air which reflect solar radiation and have a cooling effect

HOW HUMAN ACTIVITY AFFECTS CLIMATE

Anthropogenic: Relating to or resulting from the influence of humans
Human technologies affect the atmosphere; burning coal, oil and natural gas
Since the industrial revolution in the 1700’s, the amount of greenhouse gases released into the atmosphere has increased