SNC2D Unit 4 Mind Map

Ways to Classify Climate

Climate Zones:

Designed by scientist Vladmir Koppen, climate zones are determined by temperature, precipitation & plant communities.

Southern Ontario is located in the Humid Continental Climate zone

Classifying Climate

Canadian Ecozone = World Ecoregion

Ecoregion:

Climate zone focusing on the ecology of a region. Based on land forms, soil, plants and animals, and climate.

Difference between Ecoregion & Bioclimate:

Bioclimate profiles are only determined using climate, while an ecoregion takes ecology into account.

What factors affect climate?

- Distance from equator (latitude)

- Presence of large bodies of water

- Ocean air currents

- Land formations

- Height above sea level

Factors Affecting Climate

Climate System

Earth has a global climate system powered by the sun that includes air, land, liquid water, ice and living things.

The sun emits ultraviolet, visible and infrared radiation. When the sun's radiation reaches Earth, most of it is absorbed, and some is reflected back.

Latitude & Climate Zones

The Climate System

- At lower latitudes, the climate is warmer. At higher latitudes, the climate is cooler.

Near the equator, the sun's energy is more direct, and passes through less of the atmosphere. Thus, less energy is absorbed, and more reaches the surface

Near the pole, the Sun's energy is less direct, spreading out over a larger area. It also passes through more of the atmosphere. More energy is absorbed, less reaches the Earth's surface.

Amt. of sun's energy aborbed = amt. of energy raidated by the system.

Air Ocean Circulation

The atmosphere and hydrosphere are vital to the climate system: they act as heat sinks, being able to absorb and store thermal energy.

The ocean is important here because water can store much more thermal energy than air.

Thermohaline circulation:

the continuous flow of water around the world's oceans driven by differences in water temperatures in salinity

- When the air is warmer than the ocean surface, the ocean absorbs energy from air. The ocean is released back into the air if air is cooler than the ocean.

Energy Transfer

Energy Transfer In Atmosphere

Convection current: a circular current in the air and other fluids caused by the rising of warm fluid as cold fluid sinks.

Long Term Changes

Continential Drift:

Ocean currents and wind patterns change when movement of continents occur, affecting heat transfer. It also affects distribution of mass.

Why do interglacial periods and ice ages occur? Milankovitch Cycle

He summed up that Earth's orbit around the sun changes in three different ways.

- Eccentricity (shape of orbit):

Earth experiences more variation in the energy received from the sun when Earth's orbit is elongated than it does when Earth follows a more circular orbit.

- Tilt

Earth tilts anywhere from 22.5-24.5° on it's axis. The greater the tilt angle, the greater Earth's seasonal differences are.

- Precession of tilt (wobble)

A gradual change in orientation of Earth's axis greatly affects the relationship between Earth's eccentricity and tilt.

Short Term Changes

Long & Short Term Changes

Volcanic Eruptions:

Particles of sulfur dioxide reflect Sun's energy back out into space, shading Earth's surface. This results in the temporary cooling down of Earth.

Air and Ocean Currents (El Nino):

In Pacific winds and ocean currents, a change reoccurs that brings warm, moist air to the west coast of South America.

Changes In Sun's Radiation:

Decrease in radiation from sun = cooler climate

Increase in radiation from sun = warmer climate

Water Vapour Feedback Loop

Increased evaporation = warm climate, water vapour enters atmosphere. Thus, this feedback loop occurs.

The Albedo Effect:

An albedo is a measure of how much of the Sun's radiation is reflected by a surface. The albedo effect is a positive feedback loop between ice on Earth's surface and Earth's average temperature.

Rapid changes in climate over time can be explained by the Albedo effect....

Feedback Loops

Informal Climate Records:

The old fashioned way of recording climate: journals, paintings, oral histories and farming records.

Proxy Records:

Indirect records of past climates contained in natural materials.

Examples include:

- Analyzing air bubbles in ice cores, which contain data on past greenhouse gases and temperature.

- Growth rings on ancient trees and coral contain data on past temperature and climate.

- Sediment cores from ocean floor store fossils that contain data from past climates.

Clues to Past Climate

An example of an informal climate record: the Krakatoa eruption of 1883.

How do Greenhouse Gases trap Infrared Radiation??

Water, carbon dioxide, methane & Nitrous Oxide consist of three or more atoms, and have different types of atoms. These atoms can vibrate and wiggle in varying ways, and can absorb many types of energy. When infrared radiation reaches the molecules listed above, the radiation is trapped and then re-radiated back out in every direction.

Anthropogenic:

Carbon Dioxide:

Most significant source from humans, burning fossil fuels used for energy in many areas, such as industry and transportation.

Methane:

Comes from many anthropogenic sources, such as coal mining, natural gas extraction, agricultural activities (Most notably rice farming and cattle ranching) and combustion by slow smoldering of trees.

Chlorofluorocarbons (CFCs):

Gases that are used as refrigeration agents, leak out of refrigerators and air-conditioners, and are released by some industrial processes. Concentration of this gas has decreased thanks to international treaties, most notably the Montreal Protocol.

Greenhouse Gases: Anthropogenic vs. Natural

Natural:

Carbon Dioxide:

Takes up a quarter of natural greenhouse gases, natural sources include burning organic matter, volcanic eruptions and respiration of plants and animals.

Methane:

MUCH less methane in the atmosphere than CO2, sources include plant decomposition and in natural digestion.

Water Vapour:

Causes about two-thirds of the natural greenhouse effect, quantity of water vapour depends on temperature.

Nitrous Oxide:

A single molecule of nitrous oxide is about 300 times as effective as carbon dioxide, concentration is much smaller than CO2. Produced by reactions of bacteria in soil and water.

Effects of Anthropogenic Gases

Rising Sea Level:

Melting ice caps and glaciers add water to the sea, thermal expansion occurring, groundwater levels dropping.

Rising Temperatures:

In the graph below, it can be seen that the global temperature rose from 1910 to 1940, stayed even from 1940 to 1970, and started to rise more dramatically from then on.

Greenhouse Gases & Their Effects

Rise in Severe Weather:

Severe weather, such as heat waves and hurricanes, are becoming more common. Increased deaths from heat waves result, more hurricanes form: # of category 4 or 5 hurricanes have doubled in the past 40 years...

What can WE do to reduce climate change?...

Change our energy sources:

- wind power

- geothermal energy

- solar power

- hydroelectricity

- biofuels

- nuclear power

National solutions include:

- Drive less and increase travel by alternative methods, such as rail and public transit.

- Capture and store carbon dioxide released by smokestacks

- Individuals: become a steward of the environment, to benefit the environment, save peoples lives and to save money