Weather and hazards on climate change

🌪 Weather Hazards and Climate Change

🔁 Global Atmospheric Circulation

  • The atmosphere circulates in cells (Hadley, Ferrel, Polar).

  • Air rises at the equator (low pressure – wet) and sinks at 30°N/S (high pressure – dry).

  • Tropical storms form in low pressure zones near the equator.

🌊 Tropical Storms (Hurricanes, Cyclones, Typhoons)

Formation Conditions:

  • Sea temperature: 27°C+

  • Warm, moist air rises → low pressure

  • Coriolis effect causes rotation (must be 5°+ from equator)

  • Rising air = thunderstorms → develops into a storm

Structure of a Tropical Storm:

  • Eye – calm, low pressure

  • Eyewall – intense winds + rain

  • Spiral rainbands – thunderstorms + strong winds

Case Study: Typhoon Haiyan (2013, Philippines)

  • Category 5, winds up to 313 km/h, storm surge: 5m

  • Primary effects:

    • 6,300 dead

    • 90% of Tacloban destroyed

    • 1.1 million homes damaged

  • Secondary effects:

    • Looting and violence

    • Disease outbreaks

  • Responses:

    • Immediate: UN aid, rescue operations, field hospitals

    • Long-term: Rebuilding, “no-build” zone in coastal areas

UK Extreme Weather Example

(Choose one your school used – e.g., Beast from the East 2018, 2007 Floods, 2013 Storms)

🌡 Evidence for Climate Change

  • Ice cores: show CO₂ levels over 400,000+ years

  • Tree rings: wider in warm, wet years

  • Pollen records, historical records (harvest dates, paintings)

⚙ Natural Causes of Climate Change

  1. Orbital Changes (Milankovitch Cycles):

    • Eccentricity (orbit shape)

    • Axial tilt

    • Precession (wobble)

  2. Solar Output – sunspot cycles

  3. Volcanic Activity – ash and sulfur dioxide block sunlight → short-term cooling

🏭 Human Causes of Climate Change

  • Burning fossil fuels (CO₂)

  • Deforestation (less CO₂ absorbed)

  • Agriculture (methane from cattle & rice paddies)

🌍 Effects of Climate Change

Global Effects:

  • Rising sea levels → flooding (e.g. Bangladesh)

  • Melting ice caps → loss of habitat

  • More extreme weather

  • Droughts in Africa, wildfires in Australia

UK Effects:

  • Hotter, drier summers → heatwaves

  • Wetter winters → flooding

  • Sea level rise → coastal erosion

  • Changing crops (e.g., grapes in the south)

✅ Responses to Climate Change

Mitigation (Tackling the causes):

  • Alternative energy (solar, wind)

  • Carbon capture and storage

  • Afforestation

  • International agreements (e.g., Paris Agreement)

Adaptation (Dealing with the impacts):

  • Flood defences (e.g., Thames Barrier)

  • Drought-resistant crops

  • Water conservation (e.g., recycling greywater)

  • Raising buildings/coastal defences

🌪 Weather Hazards and Climate Change
🔁 Global Atmospheric Circulation

  • The atmosphere circulates in distinct cells: Hadley, Ferrel, and Polar cells, each contributing to global weather patterns.

  • Low Pressure zones occur at the equator where warm air rises, leading to moisture and cloud formation, while high pressure zones are found at approximately 30°N/S where air sinks, leading to arid conditions.

  • Tropical storms are primarily formed in these low-pressure zones, fueled by warm ocean waters and atmospheric conditions.

🌊 Tropical Storms (Hurricanes, Cyclones, Typhoons)

Formation Conditions:

  • Sea surface temperature needs to be at least 27°C or higher for sufficient heat and moisture.

  • Warm, moist air rises, creating low pressure which invites more air to flow in and rise, further developing the storm.

  • The Coriolis effect is essential for storm rotation; storms must form at least 5° latitude away from the equator to achieve the necessary spin.

  • Rising air leads to the formation of thunderstorms, which coalesce to develop into organized storm systems.

Structure of a Tropical Storm:

  • Eye: The center of the storm, characterized by calm winds and relatively low atmospheric pressure.

  • Eyewall: The area surrounding the eye, where the most intense winds and rain are found.

  • Spiral rainbands: These are bands of thunderstorms that extend outward from the eye, producing heavy rains and strong winds.

Case Study: Typhoon Haiyan (2013, Philippines)

  • Typhoon Haiyan was a Category 5 hurricane, with maximum sustained winds reaching up to 313 km/h and a storm surge that reached 5 meters.

  • Primary effects:

    • Approximately 6,300 fatalities were reported, making it one of the deadliest typhoons in history.

    • 90% of Tacloban was devastated, showcasing the sheer force of the storm.

    • Around 1.1 million homes were either partially or totally damaged, displacing thousands of residents.

  • Secondary effects:

    • The disaster led to significant looting and violence as communities struggled for essential supplies.

    • An outbreak of diseases due to contaminated water and lack of sanitation arose in the aftermath.

  • Responses:

    • Immediate: The UN provided aid, setting up rescue operations to locate survivors, and field hospitals were established to care for the injured.

    • Long-term: Recovery efforts included rebuilding infrastructure, and the establishment of no-build zones in coastal areas was mandated to prevent future risks.

UK Extreme Weather Example

  • (Choose one your school used – e.g., Beast from the East 2018, 2007 Floods, 2013 Storms)

🌡 Evidence for Climate Change

  • Ice core samples provide critical data on CO₂ levels spanning over 400,000 years, illuminating trends and fluctuations in atmospheric composition.

  • Tree ring analysis indicates wider rings in years marked by warmer and wetter conditions, aiding in understanding historical climate scenarios.

  • Pollen records assist in reconstructing past vegetation and climates, while historical records such as harvest dates and contemporary paintings offer insights into climatic impacts over time.

⚙ Natural Causes of Climate Change

  1. Orbital Changes (Milankovitch Cycles): These cycles include variations in the Earth's orbit that affect climate.

    • Eccentricity: Changes in the Earth's orbit shape can influence solar radiation received.

    • Axial tilt: Variations in the tilt of the Earth's axis can alter conditions for different seasons.

    • Precession: The wobbly rotation of the Earth affects the timing of the seasons relative to Earth’s position to the sun.

  2. Solar Output: Variations in the sun’s output over time, notably through sunspot cycles, can cause changes in climate.

  3. Volcanic Activity: Major eruptions can release ash and sulfur dioxide, leading to short-term cooling by blocking sunlight.

🏭 Human Causes of Climate Change

  • The burning of fossil fuels is a significant source of CO₂ emissions, exacerbating the greenhouse effect and global warming.

  • Deforestation reduces the number of trees available to absorb atmospheric CO₂, further contributing to greenhouse gas concentrations.

  • Agricultural practices, especially livestock farming, release methane, a potent greenhouse gas, particularly from cattle and during rice cultivation.

🌍 Effects of Climate Change

Global Effects:

  • Rising sea levels lead to increased flooding risks in coastal areas, exemplified by the experiences of countries like Bangladesh.

  • Melting polar ice caps result in habitat loss for species such as polar bears and seals.

  • More extreme weather events have become more common, including hurricanes, droughts, and flooding globally.

  • Specific regions face droughts in Africa and wildfires in Australia, highlighting the geographical variability of climate impacts.

UK Effects:

  • The UK is experiencing hotter, drier summers, leading to higher occurrences of heatwaves.

  • Wetter winters result in increased flooding incidents across various regions.

  • Coastal areas are at risk of sea-level rise, which results in significant coastal erosion.

  • Changes in agricultural patterns are noted, such as the advent of growing grapes in southern regions once thought unsuitable for viticulture.

✅ Responses to Climate Change

Mitigation (Tackling the causes):

  • Increased investment in alternative energy sources, such as solar and wind, significantly helps reduce dependency on fossil fuels.

  • Carbon capture and storage technologies aim to trap CO₂ emissions at their source and store them underground or convert them into useful products.

  • Afforestation initiatives involve planting trees to absorb CO₂ from the atmosphere, enhancing carbon sequestration efforts.

  • International agreements, such as the Paris Agreement, aim to unify countries in their efforts to reduce greenhouse gas emissions.

Adaptation (Dealing with the impacts):

  • Construction of flood defences like the Thames Barrier in London protects critical infrastructure from rising water levels.

  • Development of drought-resistant crops aims to maintain food security in changing climatic conditions.

  • Water conservation techniques, such as recycling greywater, ensure sustainable usage of water resources.

  • Raising buildings and improving coastal defences are crucial measures to protect vulnerable areas from