Earth's Extreme Forces: Climate & Change
Earth's Extreme Forces: Climate & Change
Items in this lesson
Earth's Extreme Forces: Climate & Change
Learning Objective
At the end of the lesson you will be able to describe Earth's climate patterns, explain tectonic activity, and evaluate the relationship between natural hazards and climate change.
Climate Graphs: What Are They?
Climate graphs show average temperature and rainfall for a location through the year. They help us compare different climates easily.
Temperature is shown by a red line, rainfall by blue bars. Check the months to see seasonal changes.
Equator vs Poles
The sun’s rays arrive at a low angle, so energy is spread over a larger surface area, reducing heating.
The rays travel through more atmosphere, so more energy is scattered and absorbed before reaching the surface.
Cold air sinks, creating high pressure and very little precipitation → cold and dry climate.
Ice and snow reflect heat (high albedo effect), making it even colder.
Equator
Poles
The sun’s rays are concentrated because they hit the Earth at a high angle (almost directly overhead).
This means solar energy is focused on a smaller surface area, making temperatures higher.
The rays also travel through less atmosphere, so less energy is lost.
Intense heating causes warm air to rise, leading to low pressure and frequent rainfall → hot and wet climate.
Visualising Climates
The world’s climate zones are closely linked to latitude because latitude controls how much solar energy different parts of the Earth receive.
At low latitudes (near the equator), the sun’s rays strike the Earth at a high angle, meaning energy is concentrated over a smaller area. This results in high temperatures and creates tropical climates, which are often hot and wet.
At mid-latitudes, the sun’s rays arrive at a lower angle, so energy is spread out more. This leads to moderate temperatures and seasonal climates (e.g. temperate regions).
At high latitudes (near the poles), the sun’s rays come in at a very low angle, spreading energy over a large area and passing through more atmosphere. This means less energy reaches the surface, creating cold climates.
Because the Earth is tilted on its axis, the amount of solar energy changes throughout the year, causing seasons, especially in mid-latitude regions.
Plate Tectonics: The Basics
The Earth’s crust is divided into large sections called tectonic plates, which float on the semi-molten mantle beneath them. These plates are constantly moving due to convection currents in the mantle.
As the plates move, they interact at their boundaries, and this movement creates major geological features and hazards:
At constructive (divergent) boundaries, plates move apart. Magma rises to fill the gap, forming volcanoes and new crust.
At destructive (convergent) boundaries, plates move towards each other. One plate may be forced beneath another (subduction), causing powerful earthquakes, volcanic eruptions, and the formation of mountain ranges.
At conservative (transform) boundaries, plates slide past each other. Friction builds up and is suddenly released, causing earthquakes but no volcanoes.
Overall, the movement of tectonic plates is responsible for the distribution of volcanoes, earthquakes, and mountains around the world, especially along plate boundaries.
Convergent Plate Boundaries
Convergent boundaries form when two plates move towards each other. One plate is forced under another, causing volcanoes and earthquakes.
Volcanoes and the Climate
Large volcanic eruptions can cool the global climate because they release huge amounts of ash and gases into the atmosphere.
During an eruption, ash clouds and gases such as sulfur dioxide (SO₂) are blasted high into the stratosphere.
These particles spread around the Earth and form a layer that reflects incoming solar radiation back into space.
As a result, less sunlight reaches the Earth’s surface, leading to lower global temperatures.
This cooling effect can last for months or even years, depending on the size of the eruption.
For example, large eruptions have caused temporary global cooling and shorter growing seasons in some regions.
Case Study: Eyjafjallajökull (ICELAND – HIC)
https://www.internetgeography.net/topics/eyjafjallajokull-case-study/
The 2010 eruption of Eyjafjallajökull in Iceland occurred on a constructive plate boundary where the North American and Eurasian plates move apart, allowing magma to rise beneath a glacier, which made the eruption more explosive. It produced large ash clouds that spread across Europe, grounding over 100,000 flights and causing major economic disruption, while locally it led to flooding from melting ice, damage to homes, roads, and agriculture, and the evacuation of hundreds of people. Secondary impacts were global, affecting trade and industries as far away as Kenya. Responses included evacuations, airspace closures, and emergency aid, while long-term strategies focused on improved monitoring, better air traffic management, and financial support, showing how a relatively small eruption can have widespread global impacts in an interconnected world.
Earthquake case studies
Japan Earthquake 2011
The 2011 Japan earthquake was a powerful magnitude 9.0–9.1 event caused by the subduction of the Pacific Plate beneath the Eurasian Plate at a destructive boundary. It triggered a massive tsunami, which caused most of the destruction, killing around 16,000 people, injuring thousands, and displacing about 340,000. Secondary impacts included the Fukushima nuclear disaster, widespread infrastructure damage, and economic losses of over $235 billion. Despite this, Japan’s high level of development, including strict building codes, early warning systems, and regular drills, helped reduce deaths, showing how preparedness can limit the impacts of tectonic hazards.
Haiti Earthquake 2010
The 2010 Haiti earthquake was a magnitude 7.0 event caused by movement along a conservative plate boundary between the Caribbean and North American plates. It struck near the capital, Port-au-Prince, causing catastrophic damage due to weak infrastructure and high population density. Around 230,000 people died, 300,000 were injured, and over 1 million were left homeless, with widespread building collapse and lack of basic services. Secondary impacts included disease outbreaks, food and water shortages, and slow aid distribution. Haiti’s low level of development, poor building quality, and limited emergency response greatly increased the impacts, highlighting how vulnerability affects disaster severity.
Note causes, effects, and responses.
https://www.internetgeography.net/topics/haiti-earthquake-2010/
Tropical Storms: Formation
Ingredients
Warm ocean water, moist air, and spinning of the Earth (Coriolis effect) are needed for storm formation.
Air rises, cools, condenses, and releases energy. This powers the storm, causing high winds and heavy rain.
The Process
Patterns of Tropical Storms
Tropical storms form over warm ocean waters, usually where sea surface temperatures are at least 27°C, which provides the energy needed for the storm to develop. They are most common in the Atlantic, Pacific, and Indian Oceans, particularly between 5° and 30° north and south of the equator.
Warm, moist air rises from the ocean surface, creating an area of low pressure. As the air rises, it cools and condenses to form clouds and heavy rainfall, releasing heat that powers the storm further. The Earth’s rotation (the Coriolis effect) causes the storm to spin, forming the characteristic circular shape.
Tropical storms generally move westwards due to prevailing trade winds, although their paths can later curve depending on global wind patterns. They weaken when they move over cooler water or land, as they lose their energy source.
Who Is Vulnerable to Hazards?
Vulnerability to hazards varies between countries and communities and depends on factors such as location, wealth, education, and preparedness.
Location is important because people living in high-risk areas (e.g. coastal regions, floodplains, or near tectonic plate boundaries) are more exposed to hazards like tropical storms, earthquakes, and volcanoes.
Wealth plays a major role. Poorer countries (LICs) often have weaker infrastructure, meaning buildings are less able to withstand hazards, leading to higher death tolls and damage. Richer countries (HICs) can afford stronger buildings, better technology, and emergency services.
Education and awareness affect how people respond. In countries with better education, people are more likely to understand warnings and know how to protect themselves.
Preparedness and government response also matter. Countries with early warning systems, evacuation plans, and disaster planning can reduce loss of life significantly.
Overall, poorer communities are often most at risk because they have limited resources to prepare for, respond to, and recover from hazards.
Impacts of Vulnerability
Bigger Losses
Vulnerable people (e.g., the poor, elderly, disabled) often live in risky areas.
They lose more homes, possessions, and sometimes lives when disasters happen.
Slower Recovery
They take longer to rebuild homes, get back to work, or return to normal life.
Limited money, support, and access to aid makes recovery harder.
Extra Problems
Health: More people get sick or injured.
Money: Families may become poorer.
School: Children may miss education.
Climate Change: Causes
Climate change is mainly caused by human activities that release greenhouse gases into the atmosphere. Burning fossil fuels, such as coal, oil, and gas, for electricity, transport, and industry produces carbon dioxide, which traps heat. Deforestation also contributes because fewer trees are available to absorb CO₂, leaving more in the atmosphere. Agriculture adds further greenhouse gases, with livestock producing methane and fertilizers releasing nitrous oxide. These extra gases increase the greenhouse effect, causing the Earth’s temperature to rise and leading to global climate change.
Climate Change: Impacts
Rising temperatures, melting ice caps, sea level rise, and more extreme weather events are key impacts.
Evaluating Climate Change Responses
Adaptation
Build flood defences and change farming methods to deal with changing climates.
Reduce emissions by using renewable energy, saving energy, and planting trees.
Mitigation
Review: Key Questions
Can you explain: climate graphs, climate difference between the equator and poles, action at convergent boundaries, and climate change impacts?
Summary and Reflection
