Earth: Heat Redistribution, Air Pressure & Temperature

• Heat energy redistributes around the Earth through various mechanisms

Latitude

• A geographic coordinate that specifies the north-south position of a point on the Earth's surface.

Solar Insolation

• Measurement of the amount of solar energy received per unit area per unit time.

Air Pressure

• The force exerted on a surface by the air above it as gravity pulls it to Earth.

Air Movement and Pressure

• Low atmospheric pressure causes air to move upwards, often leading to precipitation
• High atmospheric pressure causes air to move downwards, often leading to dry conditions

Global Temperature Variation

• Equator has high solar insolation which heats up a small, concentrated area, resulting in higher temperatures
• Poles have lower solar insolation spread over a larger area due to the curvature of the Earth, resulting in lower temperatures

Atmospheric Cells

• Types include Hadley, Ferrel, and Polar cells

Deserts and Atmospheric Pressure

• Deserts are not found at the equator due to high rainfall and low pressure systems
• Deserts usually form where there is high pressure.

Ocean Currents

• Redistribute heat energy around the Earth, transferring about 25% of global heat
• They have a significant influence on climate
• Oceans heat up more slowly than land but retain heat for longer
• Winds on the Earth's surface create friction with surface water, setting up ocean currents (gyres)
• The Coriolis effect deflects ocean currents

Past Causes of Climate Change

• Climate change constitutes any significant change in the Earth's climate over a long period
• The climate constantly changes
• Quaternary Period spans from 2.6 million years ago to the present day
• Global temperature has shifted between cold glacial periods (around 100,000 years) and warmer interglacial periods (around 10,000 years)
• The last glacial period ended around 15,000 years ago
• Before the Quaternary, the Earth's climate was warmer and more stable
• Global warming is the most recent indication of climate change
• Since 1880, the average global temperature has risen by 0.85°C, mostly since the mid-1970s

Natural Causes of Climate Change

• Changes in the Earth's orbit
• Variations in heat output from the Sun
• Volcanic activity & asteroid impacts

Milankovitch Cycles (Orbital Change)

• Identified by Milutin Milankovitch
• They affect the timings and seasons of the Earth's climate
• The 100,000-year eccentricity cycle coincides with alternating glacial and inter-glacial periods
• Eccentricity describes how the Earth's orbit changes from almost circular to mildly elliptical every 100,000 years

Sunspots

• Cyclical changes in solar energy output are linked to sunspots
• Sunspot Cycle describes how the number of sunspots increases to a maximum and back to a minimum over about 11 years
• Maximum sunspot activity means the Sun gives off more heat, while minimum activity reduces solar output, leading to lower temperatures on Earth
• Few sunspots between 1645 and 1715 coincided with the Little Ice Age

Volcanic Eruptions & Asteroid Impacts

• Violent eruptions blast ash, gases, and liquids into the atmosphere
• Volcanic ash blocks sunlight, reducing temperatures (short-term impact)
• Sulphur dioxide converts to sulphuric acid, acting like tiny mirrors reflecting radiation from the Sun (long-term impact)
• Volcanic Winter describes the cooling of the lower atmosphere and reduction of surface temperatures

Evidence for Natural Climate Change

• Thermometers provide direct measurements, but reliable records only go back about a hundred years
• Scientists use indirect data and proxies for past temperatures

Ice Cores

• Ice has built up over hundreds of thousands of years in polar regions
• Ice forms in layers annually, trapping tiny air bubbles
• Air bubbles contain a sample of the atmosphere from the time they were frozen, recording carbon dioxide levels

Tree Rings

• Growth rings are wider in warmer, wetter climates and narrower in colder, drier climates
• Analyzing rings tells what the climate was like throughout a tree's history
• Past climates can be reconstructed from old buildings and fossilized trees

Historical Sources

• Historical documents, such as personal diaries, paintings, and religious records, provide descriptions of past climates
• The Anglo-Saxon Chronicles record years of drought or heavy rain

Human Activities and Global Warming

• Air in the atmosphere consists of:
• Nitrogen
• Oxygen
• Argon
• Neon
• Carbon Dioxide
• Water Vapor
• Carbon dioxide helps to regulate temperatures on Earth and is one of the greenhouse gases

The Greenhouse Effect

• Describes the way that gases in the atmosphere trap heat from the Sun
• The gases act like the glass in a greenhouse, letting heat in, but prevent most of it from getting out

Human Activities that Add Greenhouse Gases

• Burning Fossil Fuels (coal, oil, and natural gas)
• Deforestation
• Agriculture

Evidence for Human-Induced Climate Change

• Global Temperature Rise: Measurements show a steep rise from around the 1950s to the present
• Sea levels have risen by about 20cm since 1900, with the rate of increase risen to 3.2mm a year
• Caused by melting glaciers and ice caps
• Thermal Expansion: Water expands as it gets warmer
• Warmer global temperatures have meant more ice has melted in the Arctic

Projections for Global Temperature Change and Sea Level Rise

• Predictions of future global temperatures and sea level rise are subject to a degree of uncertainty because scientists can not be certain how civilization will react to climate change

Tropical Storm Formation and Decay

• Tropical storms require specific conditions to form and dissipate under certain circumstances

Conditions for Formation

• Warm ocean water, at least 26.5 degrees C, to act as a fuel source
• Winds blowing in a similar direction
• Formation between the tropics

Reasons for Decay

• Landfall: Loss of the warm water fuel source as the storm moves over land
• Colder Water: Movement over ocean waters below 26.5 degrees C
• Conflicting Weather Systems: Encountering weather systems with winds blowing in different directions

Distribution of Tropical Storms

• Tropical storms do not form at the equator
• They form over deep oceans and dissipate over land
• Tropical storms only form between the tropics due to the necessary atmospheric conditions and sea temperatures
• Occur between:
• June and November in the northern tropics
• April and November in the southern tropics

Impact of Climate Change

• There is a direct relationship between the warmth of the oceans and the intensity of tropical storms
• Climate scientists predict that increasing global temperatures will lead to more intense tropical storms

Tropical Storm Hazards and Impacts

• Tropical storms pose significant natural hazards to people and the environment
• Key Terms:
• Track is the path a tropical storm takes
• Storm Surge is a rapid rise in sea level caused by low atmospheric pressure and strong winds
• Saffir-Simpson Hurricane Scale is a classification system for tropical storms based on wind speed

Physical Hazards and Impacts

• High Winds can cause injury or loss of life, damage to property, disruption of services, deforestation, habitat destruction, and damage to ecosystems
• Intense Rainfall can cause displacement, waterborne diseases, damage to property, disruption of infrastructure, soil erosion, landslides, and contamination of water sources
• Storm Surges can cause flooding, displacement, loss of life, damage to property, coastal erosion, saltwater intrusion, and destruction of coastal habitats
• Coastal Flooding can cause displacement, damage to property, disruption of services, spread of waterborne diseases, contamination of ecosystems, and destruction of habitats
• Landslides can cause injury or loss of life, damage to property, disruption of transportation routes, destruction of vegetation, and alteration of landscapes

Preparing for and Responding to Tropical Storms

• Effective preparation and response strategies are crucial to mitigating the impacts of tropical storms

Vulnerability Factors

• Countries are more vulnerable to the impacts of tropical storms due to physical, social, and economic factors

Forecasting Methods

• Atmospheric Pressure monitoring provides early information on potential tropical storm formation, requiring local readings over vast ocean areas, necessitating buoys and ship recordings
• Satellite Tracking and Radar monitors large ocean areas for cloud formations and tracks storm progress in real-time, but can be difficult to distinguish early-stage cyclones from other weather systems
• Modeling generates estimates of likely tracks, landfall points, and patterns using atmospheric and seawater data, but the models depend on good data

Communication and Protection Strategies

• Warnings, such as Hurricane Watch and Hurricane Warning, advise the public
• Emergency Measures include activating defenses like barriers, ordering evacuations, and preparing emergency services
• Public Awareness involves providing information and training on securing property, preparing emergency packs, and evacuation routes
• Infrastructure strategies include reinforcing buildings, constructing storm drains, building sea walls, and elevating houses on stilts
• Raising individual and community awareness educates people about potential dangers and how to respond

Response Actions

• Rescue Operations search for people trapped in collapsed buildings
• Aid Distribution provides food, clean water, medical care, and shelter to victims
• Infrastructure Repair restores things like power and water, and clearing roads

Hurricane Katrina Case Study (2005)

• Impacts:
• Category 4 storm causing storm surges over 6 meters
• New Orleans was severely affected due to being below sea level and levee failures
• 1 million people were made homeless
• Approximately 1,200 deaths
• Damage to oil facilities led to increased petrol prices
• Responses:
• Criticism of authorities for slow evacuation and leaving behind the poorest
• $50 billion in aid from the government as well as international aid
• Mobilization of the National Guard to restore order
• Raising levee heights around New Orleans

Typhoon Haiyan Case Study (2013)

• Impacts:
• Category 5 storm
• Tacloban was the most severely affected city
• 6,000+ deaths and millions displaced
• Widespread destruction of infrastructure
• Responses
• International assistance
• Challenges in delivering aid due to damaged infrastructure
• Issues with coordination and communication

Comparative Analysis

• Hurricane Katrina that hit the USA in 2005 caused 1800 deaths with an economic cost of $100 billion
• Typhoon Haiyan that hit the Philippines in 2013 caused 7000 deaths with an economic cost of $3 billion

Vulnerability

• Developed countries like the USA can better prepare for and respond to tropical storms due to stronger infrastructure, better resources, advanced technology, and effective governance

Earthquake Onset and Prediction

• Earthquakes happen quickly and cannot be predicted

Measuring Earthquakes

• Magnitude measures the size of an earthquake
• The size of seismic waves is measured using a seismograph
• The Richter scale is used to measure the magnitude of earthquakes

Focus and Epicenter

• The Focus is the point within the Earth where the earthquake originates
• The Epicenter is the point on the Earth's surface directly above the focus

Retrieval Questions

• Sendai 2011 (Japan) is a developed country case study
• Nepal 2015 is a developing country case study
• The Magnitude of Sendai Earthquake was 9.0
• The Sendai earthquake caused billions of dollars in damage
• Examples of secondary hazards of earthquakes include tsunamis
• Japan does frequent earthquake drills

Key Facts About the Nepal Earthquake

• Magnitude: 8.1

Development Indicators

• Gross Domestic Product (GDP) per capita is $39,285.16 in Japan and $47,334.36 in the UK
• Human Development Index (HDI) is 0.919 in Japan and 0.932 in the UK
• The UK and Japan are considered developed countries