CLIMATE CHANGE
CLIMATE CHANGE AND GLOBAL WARMING: KEY TERMS
GLOBAL WARMING
The long term increase in Earth’s average surface temperature, primarily caused by human activities such as burning fossil fuels.
CLIMATE CHANGE
Long term changes in temperature, weather patterns, and climate systems, including global warming and its wider effects such as extreme weather.
GREENHOUSE GASES
Gases in the atmosphere that trap heat by absorbing infrared radiation. Main examples include carbon dioxide, methane, and water vapour.
GREENHOUSE EFFECT
A natural process where greenhouse gases trap heat in the atmosphere, keeping Earth warm enough to sustain life. Human activity has intensified this effect.
FOSSIL FUELS
Energy sources formed from ancient organic matter, including coal, oil, and natural gas. Burning them releases carbon dioxide into the atmosphere.
CARBON DIOXIDE (CO₂)
A greenhouse gas released through respiration, combustion of fossil fuels, and deforestation. It is the main driver of human caused global warming.
METHANE (CH₄)
A potent greenhouse gas released from livestock, landfills, and natural gas extraction. It traps more heat than CO₂ but exists in smaller quantities.
OZONE LAYER
A layer of ozone gas in the stratosphere that absorbs harmful ultraviolet radiation from the sun. Distinct from greenhouse gases but part of atmospheric processes.
ATMOSPHERE
The layer of gases surrounding Earth, composed mainly of nitrogen and oxygen, with trace greenhouse gases that regulate temperature.
RADIATION
Energy emitted from the sun as shortwave radiation. Earth absorbs this and re emits it as longwave infrared radiation, which greenhouse gases trap.
CARBON (C)
A chemical element central to life and climate systems. In climate context, it refers to carbon stored or released in forms such as CO₂ and methane.
CARBON CYCLE
The movement of carbon between the atmosphere, oceans, soil, and living organisms. Human activity disrupts this balance.
CARBON FOOTPRINT
The total amount of greenhouse gases emitted by an individual, product, or activity, usually measured in CO₂ equivalents.
DEFORESTATION
The large scale removal of forests, reducing carbon storage and increasing atmospheric CO₂ levels.
INFRARED RADIATION
Heat energy emitted by Earth’s surface. Greenhouse gases absorb and re radiate this heat, contributing to warming.
ALBEDO
The reflectivity of Earth’s surface. Ice and snow have high albedo and reflect sunlight, while darker surfaces absorb more heat.
FEEDBACK LOOPS
Processes that amplify or reduce climate change. For example, melting ice reduces albedo, leading to more warming.
ANTHROPOGENIC
Originating from human activity, especially in relation to environmental change and emissions.
SEA LEVEL RISE
An increase in global sea levels due to melting ice caps and thermal expansion of warming oceans.
OCEAN ACIDIFICATION
The decrease in ocean pH caused by absorption of excess CO₂, affecting marine life and ecosystems.
GLOBAL WARMING: SCAFFOLDED EXPLANATION (YEAR 8)
WHAT IS GLOBAL WARMING?
Global warming is the gradual increase in the Earth’s temperature over time. This is mainly caused by human activities that release gases into the atmosphere.
STEP 1: THE SUN HEATS THE EARTH
Energy from the sun travels to Earth as radiation. The Earth absorbs this energy and warms up.
STEP 2: HEAT LEAVES THE EARTH
After warming up, the Earth releases some of this energy back into space as heat (infrared radiation).
STEP 3: THE GREENHOUSE EFFECT (NATURAL PROCESS)
Some gases in the atmosphere, called greenhouse gases, trap part of this heat and keep it from escaping. This is a good thing because it keeps the planet warm enough for life.
STEP 4: HUMAN ACTIVITY CHANGES THE BALANCE
Humans burn fossil fuels like coal, oil, and gas. This releases extra carbon dioxide and other greenhouse gases into the atmosphere.
STEP 5: MORE HEAT GETS TRAPPED
With more greenhouse gases, more heat is trapped. This causes the Earth’s temperature to rise more than normal.
STEP 6: THIS IS GLOBAL WARMING
The extra heating of the Earth caused by increased greenhouse gases is called global warming.
SIMPLE ANALOGY
Think of the atmosphere like a blanket. A thin blanket keeps you warm. Adding more layers traps more heat and makes you too hot.
KEY EFFECTS
Rising temperatures
Melting ice caps
Rising sea levels
More extreme weather (heatwaves, storms, droughts)
SUMMARY
Global warming happens because human activities increase greenhouse gases, which trap more heat in the atmosphere and raise the Earth’s temperature.
GLOBAL WARMING: QUESTIONS (YEAR 8)
BASIC UNDERSTANDING
What is meant by the term global warming?
What is the difference between global warming and climate change?
What is the atmosphere?
What are greenhouse gases? Give one example.
What is carbon dioxide?
PROCESS AND MECHANISMS
How does energy from the sun reach the Earth?
What happens to heat after the Earth absorbs energy from the sun?
What is infrared radiation?
What is the greenhouse effect?
Why is the greenhouse effect important for life on Earth?
HUMAN IMPACT
What are fossil fuels?
Name two human activities that release carbon dioxide.
How do humans increase the amount of greenhouse gases in the atmosphere?
Why does having more greenhouse gases lead to higher temperatures?
APPLICATION AND THINKING
Explain why the atmosphere is compared to a blanket.
What might happen if too much heat is trapped on Earth?
Give two effects of global warming.
Why might melting ice caps be a problem?
How could global warming affect weather patterns?
KEYWORD CHECK
Define: greenhouse gases
Define: fossil fuels
Define: radiation
Define: carbon
Define: methane
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