The carbon cycle and global warming Flashcards
foe sho (15 cards)
Carbon
building blocks of all
organisms.
* Carbon is essential to life and climate
regulation.
* The carbon cycle keeps atmospheric CO in₂
balance - crucial for maintaining Earth’s
temperature.
The carbon cycle
The carbon cycle is the continuous movement of
carbon atoms through Earth’s systems -
atmosphere, biosphere, hydrosphere, and
geosphere.
* There is a fixed amount of carbon – it cycles
between the Earth and the atmosphere.
How is carbon released onto and removed from the atmosphere
Carbon is released into the atmosphere by:
– Cellular respiration
– Fossil fuel emissions
– Decomposition
– Deforestation
– Fire/volcanoes
* Carbon is removed from the atmosphere by
photosynthesis.
Carbon sinks + examples
Carbon sinks are systems that absorb more carbon than they release, helping to
remove CO from the atmosphere₂ and store it long-term.
Examples of carbon sinks:
* Forests
* Oceans – dissolved CO2
* Fossil fuels (coal, natural gas, oil)
* Rocks, i.e. limestone
* Organic matter in soil
Threats to carbon sinks
Deforestation reduces forest capacity to store carbon.
* Ocean warming reduces how much CO the ocean can absorb and₂
disrupts the carbon cycle in the sea.
* Soil degradation from bad farming methods makes it harder for soil to
hold carbon.
uman Impact on the Carbon Cycle
Burning of Fossil Fuels
– Coal, oil, and natural gas are carbon-rich fuels formed over millions of years.
– When burned for energy (electricity, transportation, industry), carbon is released rapidly
as CO₂ into the atmosphere.
– This is the largest human contribution to atmospheric carbon.
Deforestation and Land-Use Change
– Trees and plants act as carbon sinks, absorbing CO through photosynthesis.₂
– Cutting down forests (especially tropical rainforests) reduces this absorption.
– Land-use changes (e.g., urbanization, agriculture) often release stored carbon from
vegetation and soil.
Agriculture and Livestock
– Methane (CH )₄ from livestock digestion (enteric fermentation) and manure management.
– Nitrous oxide (N O)₂ from fertilizer use - another potent greenhouse gas.
–
Greenhouse gasses
What Are Greenhouse Gases (GHGs)?
* Gases in the atmosphere that trap heat from
the sun, keeping Earth warm enough to support
life.
Greenhouse gases which keep the Earth warm
are:
* Carbon dioxide
* Water vapour
* Methane
* Nitrous oxide
* Ozone.
The Natural Greenhouse Effect
The greenhouse effect is a natural
phenomena that is critical for life on Earth.
1. Sunlight enters the Earth’s
atmosphere and warms the planet’s
surface.
2. Earth radiates heat back toward
space.
3. Greenhouse gases absorb and trap
some of this heat, causing the
atmosphere to warm.
The Enhanced Greenhouse Effect
Human activity has increased the level of
greenhouse gases in the atmosphere.
* This increase in greenhouse gases causes less
sunlight/heat energy to be radiated back to space.
* The large portion of sunlight/heat energy trapped
within Earth’s atmosphere is then absorbed by land
and oceans.
* Heat trapped within Earth’s spheres causing
warming of the planet.
The percentage of greenhouse gases
have increased in the atmosphere by:
– Burning fossil fuels (CO2)
– Deforestation of forests (CO2)
– Farming of livestock (CH4)
– Landfill & waste treatment (CH4)
Increases in greenhouse gases in the atmosphere have led to increasing
global temperatures.
* The average global temperature has increased by 0.8°C over the last 100
years.
Global warming
Global warming is the increase in the
average surface temperature of the Earth,
caused by the greenhouse effect.
Climate change
Climate change is the changes in long-
term weather patterns that may result in
increases or decrease in precipitation and
temperature.
Ocean Acidification
What Is Ocean Acidification?
* Ocean acidification is the process by which the ocean becomes more acidic
due to absorption of excess CO₂ from the atmosphere.
* Why It Matters – The Effects:
– Harm to Marine Life – damaging to coral and shells of organisms (turtles, crab, plankton
etc.).
– Economic Impact – fisheries and aquaculture.
– Slower Ocean Carbon Storage.
Human activities (burning fossil fuels, deforestation) release large
amounts of CO₂ into the atmosphere.
2. About 25–30% of this CO₂ is absorbed by the oceans.
3. CO reacts with seawater to form₂ carbonic acid.
4. Carbonic acid dissociates into hydrogen ions (H )⁺ and
bicarbonate.
5. The increase in hydrogen ions lowers the pH of seawater, making
it more acidic.
Some evidence that the Earth’s average temperature is rising include
Melting sea ice
* Melting permafrost
* Rising sea levels
* Extreme weather events
* Loss of biodiversity
Melting Sea Ice
Oceans are carbon sinks.
* Oceans absorb 90% of the solar energy from
the sun.
* The warmer the oceans get, the harder it is to
absorb heat energy and it is reflected into the
atmosphere.
* Warmer water causes the ice to melt and this
water absorbs more solar energy.
Melting Permafrost
Permafrost is permanently frozen ground that
stores carbon from plant material frozen
during the last Ice Age.
* ⅔ of the Earth’s permafrost is predicted to be
melted by 2200.
* Vast amounts of carbon will be released if it
melts.
