Dynamics of Climate Change

Dynamics of Climate Change

Energy Transfer in the Climate SystemEnergy Transfer in the Climate System

◊ Earth’s climate is a complex system.◊ A system is a group of independent parts that

work together to form a single, functioning whole.◊ An open system is a system in which energy and

matter cross the system’s boundary. (your body)◊ A closed system allows energy but not matter to

cross the boundary of the system. (The Earth’s climate system)

◊ As a closed system, Earth must constantly cycle the matter and energy within it’s boundary.

◊ Earth’s climate is a complex system.◊ A system is a group of independent parts that

work together to form a single, functioning whole.◊ An open system is a system in which energy and

matter cross the system’s boundary. (your body)◊ A closed system allows energy but not matter to

cross the boundary of the system. (The Earth’s climate system)

◊ As a closed system, Earth must constantly cycle the matter and energy within it’s boundary.

◊ Interactions among different forms of matter and energy in Earth’s climate system create feedback loops.

◊ A Feedback loop is a process in which part of a system’s output is returned to the input.

◊ In the Earth’s climate system, many feedback loops affect the conditions of the atmosphere, ocean and land.

◊ Interactions among different forms of matter and energy in Earth’s climate system create feedback loops.

◊ A Feedback loop is a process in which part of a system’s output is returned to the input.

◊ In the Earth’s climate system, many feedback loops affect the conditions of the atmosphere, ocean and land.

◊ A positive feedback loop acts to increase the effects of the interacting parts.

◊ Example: effect of melting ice, decreases albedo (reflected light of surface), which increases warming, which increases the amount of melting ice, and so on.

◊ The small initial change in climate can lead to larger and larger changes.

◊ A positive feedback loop acts to increase the effects of the interacting parts.

◊ Example: effect of melting ice, decreases albedo (reflected light of surface), which increases warming, which increases the amount of melting ice, and so on.

◊ The small initial change in climate can lead to larger and larger changes.

◊ Negative feedback loops decreases the interacting parts and help maintain the system’s equilibrium.

◊ Checks and balances to prevent, slow or reverse change in a system.

◊ Example: global warming increases rate of evaporation, increased water in atmosphere creates clouds, clouds create more albedo, which produces a cooling effect.

◊ Negative feedback loops decreases the interacting parts and help maintain the system’s equilibrium.

◊ Checks and balances to prevent, slow or reverse change in a system.

◊ Example: global warming increases rate of evaporation, increased water in atmosphere creates clouds, clouds create more albedo, which produces a cooling effect.

Types of Energy TransferTypes of Energy Transfer

◊ Radiation: transfer of energy as electromagnetic radiation. • E.G. Sun to Earth, heat from fire, etc.

◊ Conduction: transfer of energy between 2 objects in direct contact. Moves from an area of high heat to lower heat.• E.G. hot plate on stove to frying pan to egg.

◊ Convection: transfer of thermal energy by highly energized molecules.• E.G. lava lamp

◊ Radiation: transfer of energy as electromagnetic radiation. • E.G. Sun to Earth, heat from fire, etc.

◊ Conduction: transfer of energy between 2 objects in direct contact. Moves from an area of high heat to lower heat.• E.G. hot plate on stove to frying pan to egg.

◊ Convection: transfer of thermal energy by highly energized molecules.• E.G. lava lamp

Energy Transfer in AtmosphereEnergy Transfer in Atmosphere

◊ Land and water gain thermal energy by absorbing the Sun’s short-wave radiation.

◊ As Earth warms, it emits long-wave radiation to the atmosphere, which heats the air and contributes to greenhouse effect.

◊ Conduction heats the air through collisions between molecules in the ground and in the air.

◊ Convection moves warm air from close to the ground upward and cool air from higher in the atmosphere downward.

◊ Land and water gain thermal energy by absorbing the Sun’s short-wave radiation.

◊ As Earth warms, it emits long-wave radiation to the atmosphere, which heats the air and contributes to greenhouse effect.

◊ Conduction heats the air through collisions between molecules in the ground and in the air.

◊ Convection moves warm air from close to the ground upward and cool air from higher in the atmosphere downward.

Convection, Conduction and Radiation transfer

heat in Earth’s Atmosphere

Convection, Conduction and Radiation transfer

heat in Earth’s Atmosphere

Energy Transfer in the Oceans

Energy Transfer in the Oceans

Uneven heating on Earth creates winds. Winds create currents of water that

redistribute thermal energy at the ocean surface.

Deeper, colder currents also move slowly along the ocean floor

Like air masses, large masses of water can move vertically and horizontally.

Cold water = dense and sinks, pushing warm water out of the way

Salt water = dense and sinks.

Uneven heating on Earth creates winds. Winds create currents of water that

redistribute thermal energy at the ocean surface.

Deeper, colder currents also move slowly along the ocean floor

Like air masses, large masses of water can move vertically and horizontally.

Cold water = dense and sinks, pushing warm water out of the way

Salt water = dense and sinks.

Temperature, salinity, density of water create continuous, twisting ocean current that mixes ocean waters.

Sometimes called the “Great Conveyor Belt” This pattern is known as thermohaline circulation. Creates a global system of thermal energy

distribution

Temperature, salinity, density of water create continuous, twisting ocean current that mixes ocean waters.

Sometimes called the “Great Conveyor Belt” This pattern is known as thermohaline circulation. Creates a global system of thermal energy

distribution

Global Warming and Thermohaline Circulation

Global Warming and Thermohaline Circulation

Scientists are worried that global warming will affect the current pattern of circulation.

Higher temps increased ice melting increases fresh water decreases salt content in northern water

Higher temps increased evaporation increased salt levels in tropics

Changes in ocean circulation patterns could have a negative effect on living things (manta ray) in the ocean by changing patterns of upwelling.

Upwelling brings nutrients from sea floor to surface currents.

Scientists are worried that global warming will affect the current pattern of circulation.

Higher temps increased ice melting increases fresh water decreases salt content in northern water

Higher temps increased evaporation increased salt levels in tropics

Changes in ocean circulation patterns could have a negative effect on living things (manta ray) in the ocean by changing patterns of upwelling.

Upwelling brings nutrients from sea floor to surface currents.

Energy Transfer

The importance of winds and ocean currents to global climate is seen best when there is a disruption to the system.

Every few years in the tropics, there are events called El Nino and La Nina.

El Nino

Winds blowing west weaken and might reverse

Warm waters in the western Pacific move eastward, preventing cold water from upwelling

Can trigger changes in precipitation and temperature across North America.

Heavy rains in California can lead to landslides

La Nina

Stronger than normal winds push warm Pacific waters farther west, towards Asia.

Cold, deep-sea waters well up strongly in the Eastern Pacific

Colder temperatures to northwestern North America.

Moisture pushed away from N.America, parched lands.

Earth’s Energy BudgetEarth’s Energy Budget

Nearly a third of solar energy reaching Earth is reflected back.

The 70% that is absorbed warms the ground, water, and air.

The energy budget is a description of the total energy exchange within a system; how much energy enters from the Sun and how much leaves the Earth system.

Nearly a third of solar energy reaching Earth is reflected back.

The 70% that is absorbed warms the ground, water, and air.

The energy budget is a description of the total energy exchange within a system; how much energy enters from the Sun and how much leaves the Earth system.

Percentage of Absorbed and Reflected Energy

Percentage of Absorbed and Reflected Energy

Greenhouse Gases» The concentration of carbon dioxide in

Earth’s atmosphere increased from 315 parts per million (ppm) to 370ppm.

» 99% of the atmosphere is made up of nitrogen gas and oxygen gas.

» Neither absorbs infrared radiation or contributes to greenhouse gases.

» Carbon dioxide and water are the 2 most abundant greenhouse gases in our atmosphere.

Water Vapour?

» Responsible for 65-85% of greenhouse effect

» Water is not added or removed to the atmosphere in significant amounts by humans.

» Temperature does control the amount of water in the atmosphere.

» Higher temperature = more evaporation

CO2 Sources and Sinks» A sink is a process that removes

greenhouse gases from the atmosphere.

» Plants are sinks» Burning of fossil fuels and animal

respiration are the major sources» Phytoplankton (microorganisms)

can absorb a lot of carbon dioxide as well.

Methane: greenhouse gas

» Produced in wetlands (bogs and swamps), rice paddies, termites and cattle naturally.

» Landfills, processing coal and natural gas and manure also emit methane.

» Suggestions? Make cows wear backpacks to capture the methane and use it as a fuel, feed cows clover and alfalfa to reduce methane, stop eating beef.

Methane backpack!

Ozone Ozone (O3) occurs naturally in the atmosphere

and blocks UV radiation from the Sun. Since 1970, there has been a slow decline in

the total ozone and a “hole” appeared over Antarctic.

Not actually a hole, just an area where the ozone is thinning more than other areas around it.

Cause: human-made gases that contain chlorine

Ground-Level Ozone

Smog-forming pollutant

Produced when sunlight reacts with chemicals and vehicle exhaust (hydrocarbons and nitrogen oxides)

Can contribute to global warming.

Halocarbons Formed when carbon is mixed with a halogen

(iodine, fluorine, chlorine) Human-made Chlorofluorocarbons (CFCs) are best known in

solvents, cleaners and coolants in fridges and air conditioners.

Absorb infrared radiation so they are greenhouse gases and also break apart ozone molecules

Remain in atmosphere for so long and continue to do damage

Banned in 1987.