Earth Science Extended Response

Year 10 - Science

Compare the cause(s) and effect(s) of the greenhouse effect and the enhanced greenhouse effect

Aspect	Greenhouse Effect (Natural)	Enhanced Greenhouse Effect (Human-Caused)
Cause	- Natural greenhouse gases like carbon dioxide, methane, and water vapor trap heat.	- Human activities such as burning fossil fuels, deforestation, and industrial processes increase greenhouse gas levels.
Process	- Sunlight warms the Earth’s surface. - Earth emits heat as infrared radiation. - Greenhouse gases absorb and re-radiate heat back to the surface.	- Same process as natural effect, but extra greenhouse gases trap more heat. - Leads to warming beyond natural levels.
Effect on Temperature	- Maintains Earth’s average temperature (~15°C). - Keeps climate suitable for life.	- Causes global temperatures to rise (global warming). - Leads to climate change.
Impact on Life & Environment	- Supports ecosystems and biodiversity. - Maintains water cycles and stable weather patterns. - Essential for human survival.	- Melting ice sheets and glaciers. - Rising sea levels threatening coastal areas. - More frequent and severe extreme weather events (heatwaves, storms, floods). - Disruption to ecosystems and agriculture, threatening food security.
Scale	- Natural and stable over long periods.	- Rapid and increasing due to human influence.
Key Comparison	- Sustains life. - Caused by natural processes. - Maintains stable climate.	- Produces harmful consequences. - Caused by human activities. - Disrupts climate and ecosystems.

 Explain the causes and impacts of El Nino and La Nina on Australia.

Category	El Niño	La Niña
Oceanic Causes	Central and eastern tropical Pacific Ocean warms above average.	Central and eastern tropical Pacific Ocean cools below average.
Atmospheric Causes	Trade winds weaken; reduced moisture transport to western Pacific; Walker Circulation shifts eastward.	Trade winds strengthen; increased moisture transport to western Pacific; Walker Circulation intensifies.
Temperature	Hotter than average across much of Australia, especially inland and eastern regions.	Cooler than average across much of Australia, particularly in northern and eastern regions.
Rainfall	Below-average rainfall; droughts likely in eastern and northern regions.	Above-average rainfall; increased flooding risk, especially in north and east.
Extreme Weather Events	Increased frequency and intensity of heatwaves and bushfires.	More frequent and intense tropical cyclones, storms, and floods.
Environmental Impacts	Soil moisture deficits, water shortages, and stress on ecosystems; reduced river flows.	Soil saturation, river flooding, and increased wetland water levels; ecosystems benefit from higher rainfall but may be disrupted by floods.
Agricultural Impacts	Crop failures, reduced pasture growth, livestock stress, and lower productivity.	Improved crop yields in some areas due to rainfall, but flooding can destroy farmland and damage crops.
Economic Impacts	Higher costs for firefighting, water management, and emergency relief; reduced agricultural income.	Costs associated with flood damage, infrastructure repairs, and disaster relief; some economic benefit for agriculture if floods are not severe.
Social Impacts	Water restrictions, heat-related health risks, reduced quality of life in affected areas.	Displacement from flooding, property damage, health risks from waterborne diseases, and disruption to communities.

Occur every 2-7 years, lasts 3-5 years

Explain the carbon cycle outlining the following key processes: photosynthesis, respiration, decomposition, consumption, combustion, mining, sedimentation (fossil fuel formation).

• Carbon cycle: Movement of carbon through atmosphere, living organisms, oceans, and rocks.

• Purpose: Recycles carbon for life; stores some for millions of years.

• Processes:

  • Short-term: Photosynthesis, respiration

  • Long-term: Sedimentation, fossil fuel formation

• Photosynthesis:

  • Plants, algae, bacteria absorb CO2

  • Convert CO2 + sunlight → glucose + oxygen

  • Carbon enters food chain

• Consumption:

  • Animals eat plants/other animals → take in carbon

  • Respiration releases CO2 as glucose is broken down for energy

• Decomposition:

  • Dead organisms broken down by fungi/bacteria

  • Releases carbon back into soil, air, or water (CO2 or methane)

• Long-term storage:

  • Buried plant/animal matter → compressed → fossil fuels (coal, oil, gas)

  • Stores carbon for millions of years

• Human impact:

  • Mining/drilling → fossil fuels extracted

  • Burning fuels → rapid CO2 release

  • Disrupts natural carbon balance → contributes to climate change

• Summary:

  • Carbon moves between living things, air, water, rocks

  • Natural processes regulate flow, humans increase atmospheric CO2

Contrast the difference between weather and climate.

Aspect	Details
Weather	- Short-term atmospheric conditions in a specific place and time. - Includes temperature, humidity, precipitation, cloud cover, wind speed, and air pressure. - Can change rapidly, even within hours or minutes. - Influences daily decisions, like what to wear or whether to carry an umbrella. - Example: A hot morning turning into an afternoon thunderstorm.
Climate	- Long-term patterns and averages of weather over at least 30 years. - Shows what weather is typical for a region. - Includes average temperature, rainfall patterns, seasonal trends, and extreme events. - Relatively stable over long periods, despite daily variations. - Example: Northern Australia has a wet season with heavy rainfall and a dry season with minimal rain.
Key Differences	- Timescale: Weather is short-term; climate is long-term. - Variability: Weather is highly variable; climate is relatively stable. - Predictability: Weather can be forecasted for a few days; climate shows trends over decades. - Purpose/Impact: Weather affects daily decisions; climate guides long-term planning in agriculture, infrastructure, and policy.
Summary	- Weather is what happens now; climate is what we expect to happen over time.

Explain using an example, the impact global warming is having on the loss of sea ice and increased ocean temperatures. Include explanation of Albedo.

• Global warming is changing the oceans and polar regions, especially sea ice and ocean temperatures.

• Higher global temperatures from greenhouse gases are making sea ice melt faster in the Arctic and Antarctic.

• Satellites show that Arctic sea ice is shrinking each summer, leaving less ice all year.

• Sea ice has high albedo, meaning it reflects sunlight back into space.

• When ice melts, dark ocean water is exposed, which absorbs more heat and warms up.

• This causes a cycle where warmer water melts even more ice.

• Warmer oceans affect marine life, like causing coral bleaching when corals lose the algae that give them color and energy.

• Hotter oceans can also make storms stronger and change ocean currents, affecting ecosystems and people.

• Melting sea ice and warmer oceans together show how global warming causes chain reactions in the environment.

• Losing reflective ice means oceans absorb more heat, speeding up warming and ice loss.

• This example shows how climate systems are connected and how human-caused global warming is changing the planet.

Discuss how marine organisms are being impacted by current global warming trends (e.g. polar bears, coral species, fisheries, seagrasses)

• Polar Bears

  • Need sea ice to hunt seals.

  • Ice melts earlier and forms later because of global warming.

  • Less hunting time → malnutrition and fewer babies.

  • Shows how losing habitat harms animals.

• Coral Species

  • Warmer oceans cause coral bleaching.

  • Corals lose algae that give them energy.

  • Bleached corals can get sick and die.

  • Affects fish and other animals that live in coral reefs.

• Fisheries (Fish)

  • Fish migrate to cooler waters as oceans warm.

  • Shifts reduce fish availability for human consumption.

  • Affects livelihoods of communities dependent on fishing.

  • Warmer water can cause toxic algae blooms → producing toxins that affect fish and humans.

• Seagrasses

  • Heat and acid in oceans slow their growth and resilience.

  • Harder for them to make energy and store carbon.

  • Losing seagrass → less biodiversity and weaker carbon absorption → makes climate change worse.

• Overall Impact

  • Global warming disrupts marine life across polar, tropical, and coastal regions.

  • Human-induced climate change threatens ecosystems, highlighting the need to reduce greenhouse gas emissions.

Describe the importance of ocean currents in regulating global climate patterns and their effects on marine life. Incorporate explanations of thermohaline circulation and the global conveyor belt. Include research on a specific current as a case study.

Role of Ocean Currents in Climate

• Ocean currents move heat and nutrients around the world, helping regulate global climate.

• Warm surface currents, like the Gulf Stream, carry heat from the equator to the poles.

• Cold currents carry cooler water back toward the tropics.

• This flow balances temperatures, preventing regions from becoming too hot or too cold.

• Without currents, coastal climates would be harsher, affecting humans and ecosystems.

Thermohaline Circulation and the Global Conveyor Belt

• Thermohaline circulation happens because of differences in water temperature and salt levels.

• Cold, salty water is dense and sinks; warm, less salty water rises, creating a continuous flow.

• The sinking and rising of water drives movement around the globe, forming the “global conveyor belt.”

• The conveyor belt connects all oceans, spreading heat, oxygen, and nutrients worldwide.

• This slow system keeps the Earth’s climate stable over long periods.

Effects on Marine Life

• Upwelling brings nutrients from deep water to the surface, which helps phytoplankton grow.

• Nutrient-rich areas become hotspots for biodiversity, supporting lots of fish.

• Stable currents help species migrate, reproduce, and find food.

• If currents change because of global warming, ecosystems and human food supplies could be disrupted.

Case Study: Gulf Stream

• Water Temperature:

  • Tropics: ~25–28°C

  • North Atlantic: ~10–15°C

• How it Moves:

  • Warm surface water flows north along the eastern coast of North America.

  • As it reaches the North Atlantic, the water cools and becomes denser.

  • Dense, salty water sinks to the deep ocean, then slowly flows south and eventually rises elsewhere.

  • This sinking and rising links the Gulf Stream to the global conveyor belt, moving heat and nutrients worldwide.

• Influences on Climate:

  • Warms northern Europe, keeping winters milder than other regions at the same latitude.

  • Adds energy to storms and hurricanes in the Atlantic because of the warm water.

  • Affects rainfall patterns and seasonal weather in North America.

• Effects on Marine Life:

  • Serves as a migration route for fish like tuna and swordfish.

  • Supports plankton growth, which feeds larger marine species.

  • Nutrient mixing zones create productive fishing areas essential for ecosystems and humans.

• Interesting Features:

  • Flows at over 5 km/h in some areas, unusually fast for an ocean current.

  • Moves more water than all the world’s rivers combined.

  • Called a “giant river in the ocean” because of its size and strength.

  • Its movement and power show how ocean currents are essential for climate regulation and marine life.