Comprehensive Biosphere, Carbon Cycle, and Climate Change Key Concepts

What is the biosphere?

The biosphere is the region at the surface of the Earth where all life exists, consisting of all ecosystems.

How deep does the biosphere extend below the Earth's surface?

The biosphere extends about 10 metres below the surface.

What does the geosphere include?

The geosphere includes the solid, non-living parts of the Earth, such as rocks, minerals, landforms, the Earth's crust, mantle, and core.

What is the lithosphere?

The lithosphere is part of the geosphere that includes mountains, continents, and the ocean floor.

What does the hydrosphere encompass?

The hydrosphere encompasses all the water on Earth, including oceans, rivers, lakes, and more.

What percentage of Earth's water is salt water?

About 97% of Earth's water is salt water found in the oceans.

How much of the hydrosphere is liquid fresh water?

Only 1% of the hydrosphere is liquid fresh water, most of which is below ground.

What gases compose the atmosphere?

The atmosphere is composed of nitrogen (78%), oxygen (21%), carbon dioxide (0.04%), and other gases in very small amounts.

What is the primary function of the atmosphere?

The atmosphere contains oxygen, reflects and absorbs radiation, and helps keep the planet warm.

What is the word equation for photosynthesis?

Carbon dioxide + water -> glucose + oxygen.

How do plants use carbon dioxide?

Plants use carbon dioxide and light to make the sugars they need to grow through photosynthesis.

What is the word equation for respiration?

Glucose + oxygen -> carbon dioxide + water + energy.

How does carbon move through the biosphere?

Carbon moves through the biosphere by traveling through food chains, where plants are eaten by animals.

What role do decomposers play in the carbon cycle?

Decomposers break down organic matter, releasing carbon dioxide into the atmosphere through microbial respiration.

What happens to carbon when organisms fossilize?

When organisms fossilize, carbon is transferred from the biosphere to the geosphere, becoming sedimentary rock.

What is the word equation for combustion?

Fuel + oxygen -> carbon dioxide + water.

How does the ocean absorb carbon?

The ocean absorbs carbon from the atmosphere, which can lead to ocean acidification.

What is created when shells and bones of marine animals are deposited on the sea floor?

They create limestone, which locks carbon within the seabed.

What happens to carbon locked in limestone?

Carbon can be released back into the atmosphere if the limestone dissolves.

How does the geosphere transfer carbon to the hydrosphere?

Parts of the geosphere are weathered and eroded, running off into surface water catchments to re-join the hydrosphere.

What is a carbon source?

Anything that produces or releases carbon into the atmosphere or is used by an organism to synthesize biomass.

Give examples of natural and human-caused carbon sources.

Natural sources include volcanic eruptions; human-caused sources include the burning of fossil fuels.

What is a carbon sink?

Any reservoir that absorbs more carbon dioxide from the atmosphere than it releases, reducing greenhouse gas concentrations.

Name three examples of carbon sinks.

Forests, oceans, and soils.

How do oceans act as a carbon sink?

Oceans absorb significant amounts of atmospheric carbon dioxide, helping to regulate Earth's climate.

What negative effect does increased atmospheric CO2 have on oceans?

It leads to ocean acidification, forming carbonic acid which lowers pH and threatens marine life.

How do humans interact with the carbon cycle through fossil fuel combustion?

Burning fossil fuels releases vast amounts of CO2 into the atmosphere, adding carbon faster than natural processes can remove it.

What is the impact of deforestation on carbon reservoirs?

It releases stored carbon, reduces the size of terrestrial carbon reservoirs, and increases atmospheric CO2 levels.

What greenhouse gases are released by agricultural practices?

Methane (CH₄) and nitrous oxide (N₂O).

What is the role of the atmosphere in the carbon cycle?

It serves as a temporary reservoir for CO₂ and CH₄.

How does deforestation affect the terrestrial biosphere's capacity to absorb CO2?

It reduces the capacity due to loss of trees and vegetation that absorb CO2 during photosynthesis.

What happens to oceans as a result of increased CO2 levels?

They experience acidification and reduced carbon uptake efficiency.

What is the long-term role of fossil fuels in the carbon cycle?

They serve as long-term carbon storage, but their rapid depletion releases stored carbon.

How does soil contribute to carbon storage?

Soil stores organic carbon, but erosion and land use changes reduce its carbon retention.

What is the difference between weather and climate?

Weather is the short-term state of the atmosphere, while climate is the long-term average of weather conditions over 10 years or more.

What are greenhouse gases?

Gases that include methane, carbon dioxide, water vapor, and nitrous oxide, contributing to the greenhouse effect.

Describe the greenhouse effect.

A natural process that warms the Earth's surface by trapping outgoing infrared radiation emitted by the Earth.

How does the Sun's energy contribute to the greenhouse effect?

The Sun emits shortwave radiation that warms the Earth's surface, which then emits longwave infrared radiation.

What role do greenhouse gases play in the greenhouse effect?

They absorb outgoing infrared radiation and re-emit it, warming the Earth's surface.

What is albedo and how does it relate to the greenhouse effect?

Albedo refers to the reflectivity of surfaces; high albedo surfaces reflect more radiation back into space, affecting the greenhouse effect.

What happens to radiation absorbed by land, oceans, and vegetation?

It is emitted back toward the atmosphere as longwave infrared radiation.

Why is the greenhouse effect essential for life on Earth?

It warms the planet, making it habitable by maintaining a stable climate.

What effect does the re-emission of infrared radiation have on Earth's atmosphere?

It traps heat, keeping the planet warmer than it would be otherwise.

What would Earth's average temperature be without the greenhouse effect?

About -18°C.

How do ice cores provide evidence for climate change?

They trap air bubbles that can be measured for carbon dioxide concentration, indicating past temperatures.

What does the presence of different pollen shapes indicate in climate studies?

Different plants produce unique pollen shapes, allowing scientists to analyze past climates based on pollen found in peat bogs.

What are moraines and what do they indicate?

Moraines are dam-like deposits formed by glaciers, indicating the extent of glacial retreat and past climates.

How can fossil records indicate changes in climate?

Plant fossils can show shifts from rainforest to grasslands, indicating reduced rainfall, while marine fossils can indicate changes from aquatic to terrestrial environments.

What is the difference between global warming and climate change?

Global warming refers specifically to the rise in Earth's average surface temperature, while climate change encompasses all long-term changes to Earth's climate.

What human activities are primarily driving climate change?

Burning fossil fuels, deforestation, and large-scale agriculture.

What has been the trend in Earth's average surface temperature since 1880?

It has increased by approximately 0.07°C per decade.

What has been the rate of temperature increase since 1981?

The rate has more than doubled to 0.18°C per decade.

What percentage of the warming rate since the 1950s exceeds historical trends?

The warming rate exceeds 99% of all 51-year trends observed in the pre-industrial era.

What recent trend has been observed in Arctic sea ice cover?

Arctic sea ice has been shrinking dramatically, with decreases in thickness, extent, and duration.

What evidence do scientists use to infer past climates from glacial deposits?

Mapping the location of glacial deposits helps infer the degree of climate warming in that region.

How do temperature trends correlate with industrial activities?

There is a strong correlation between rising temperatures and industrial activities, particularly fossil fuel combustion.

What does the term 'recent extremes' refer to in the context of climate data?

It refers to the fact that eight of the ten hottest years on record have occurred in the last decade.

What role do glaciers play in understanding climate change?

Glaciers gouge rock and soil, leaving deposits that indicate past climate conditions as they melt and retreat.

Why is the analysis of peat bogs important in climate studies?

Peat bogs preserve pollen that can be analyzed to determine the climate conditions of different time periods.

What is the significance of the concentration of carbon dioxide in ice cores?

Higher concentrations of carbon dioxide correlate with higher temperatures, indicating past climate conditions.

How does climate change affect weather patterns?

Climate change leads to altered weather patterns, including increased frequency of extreme weather events.

What is the relationship between global warming and greenhouse gases?

Global warming is largely driven by the release of greenhouse gases from human activities.

What does the term 'steady rise' refer to in temperature trends?

It refers to the consistent increase in Earth's average surface temperature over time.

What recent trend has been observed in Antarctic sea ice levels as of February 2025?

Antarctic sea ice was 26% below average.

How does the variability of Antarctic sea ice compare to Arctic sea ice?

Antarctic sea ice has shown more variability, with Arctic sea ice being 8% below average.

What long-term trend has been observed in sea ice levels since the early 1900s?

There has been a consistent decline in sea ice, with sharper drops in recent decades due to warming and feedback loops.

What was the pre-industrial baseline level of atmospheric CO₂?

CO₂ levels hovered around 280 ppm before the Industrial Revolution.

What record high level of atmospheric CO₂ was reached in 2024?

426.91 ppm, marking a 50% increase over pre-industrial levels.

What are the primary drivers of the recent rise in atmospheric CO₂ levels?

Fossil fuel use, deforestation, and industrial processes.

What are some consequences of elevated CO₂ levels in the atmosphere?

It traps heat, intensifies global warming, triggers extreme weather, ocean acidification, and disrupts ecosystems.

How are rising temperatures, shrinking sea ice, and surging CO₂ interconnected?

More CO₂ leads to higher temperatures, which melt sea ice, reducing Earth's reflectivity and accelerating warming.

What is the natural greenhouse effect?

A vital planetary process where atmospheric gases trap heat, maintaining a stable temperature of around 15°C.

What distinguishes the enhanced greenhouse effect from the natural greenhouse effect?

The enhanced greenhouse effect is intensified by human activities that increase greenhouse gases, trapping excess heat.

What is a major source of carbon dioxide emissions from fossil fuels?

The burning of coal, oil, and natural gas releases CO₂ as a waste product.

How much CO₂ is added to the atmosphere annually from fossil fuel combustion?

Over 7 thousand million tonnes of CO₂.

What are the two main ways land clearing contributes to CO₂ levels?

Burning forests releases CO₂, and the loss of vegetation reduces CO₂ absorption.

How much forest area is cleared each year, and what is its significance?

An area equal to England and Scotland combined is cleared, releasing large amounts of CO₂.

How did carbon dioxide levels vary before industrialization compared to after 1800?

Levels varied less than in the previous 10,000 years, but have risen significantly since 1800.

What are some sources of methane emissions?

Rice paddies, livestock (especially ruminants), and landfills.

How do rice paddies contribute to methane emissions?

Anaerobic microorganisms release methane as they decompose organic matter in submerged conditions.

What role do ruminant animals play in methane emissions?

They produce methane gas during digestion due to bacteria in their rumen.

What is a common waste management practice that contributes to methane emissions?

Burying household waste at landfill sites.

What is the feedback loop involving CO₂ and sea ice?

Increased CO₂ leads to warming, which melts sea ice, reducing reflectivity and accelerating further warming.

What are the implications of the enhanced greenhouse effect on global temperatures?

It leads to a faster rate of global warming and climate change.

What is the primary greenhouse gas produced by decomposing organic waste in landfills?

Methane

What process in landfills reduces levels of waste?

Decomposition by anaerobic microorganisms

What gases are released from biomass burning?

Methane, carbon dioxide, and nitrous oxide

What is the effect of sulfur dioxide (SO2) in the atmosphere?

It causes the formation of sulfuric acid aerosol, which has a greenhouse effect.

How do humans contribute to sulfur dioxide emissions?

By burning fossil fuels, particularly coal with high sulfur content.

What are halocarbons?

Synthetic carbon compounds containing fluorine, chlorine, bromine, or iodine.

Name two examples of halocarbons.

Chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCS).

What are abiotic factors in the context of climate change?

Non-living physical and chemical components of the environment.

How is global average temperature affected by climate change?

It is rising due to the Enhanced Greenhouse Effect (EGHE).

What is one consequence of melting ice caps due to climate change?

Contributing to sea level rise.

What happens to permafrost as a result of climate change?

It thaws, releasing methane and destabilizing infrastructure.

What causes rising sea levels?

Thermal expansion of seawater and melting land ice.

What is a significant impact of changing weather patterns due to climate change?

Increased frequency and intensity of extreme weather events.

How might ocean circulation be affected by climate change?

Warming and freshwater input may disrupt thermohaline circulation.

What is one major risk to biodiversity from climate change?

Species unable to adapt or migrate face extinction.

Which ecosystems are particularly vulnerable to climate change?

Coral reefs, rainforests, and alpine ecosystems.