Weather hazards and climate change Flashcards
What is the atmosphere?
The atmosphere is the layer of air surrounding the Earth’s surface which extends hundreds of kilometres high
What is weather and what is climate?
Weather is the short term day to day conditions of the atmosphere
while Climate is the long term average temperature and rainfall.
Which part of the atmosphere does weather take place in?
Troposphere
What is the Coriolis effect and its impacts on the weather of the uk?
Apparent force, due to the spinning of the Earth, which deflects movement of particles and wind.
In the UK, which winds are blown from the south due to the Ferrell cell but the earth spins to the right causing the prevailing wind to hit the UK in a south-westerly direction.
What is a glacial and an interglacial?
A glacial is a period of cold while an interglacial is a period of warm?
What are the patterns of climate across the UK
The general pattern of the climate across the UK has four distinct regions:
south-east – cold winters, warm and dry summers
south-west – mild and very wet winters, warm and wet summers
north-west – mild winter, cool summers and heavy rain all year
north-east – cold winter, cool summers and steady rain all year
What was the last major cold period?
The last major cold period was known as the Pleistocene. It started 2.6 million years ago and ended just 10,000 years ago. Since then, conditions have been warmer. This current warm phase is known as the Holocene. The Holocene and Pleistocene are part of the Quaternary Period of Earth’s history.
What human factors increase global warming?
Burning fossil fuels, eg coal, gas and oil - these release carbon dioxide into the atmosphere.
Deforestation - trees absorb carbon dioxide during photosynthesis. If they are cut down, there will be higher amounts of carbon dioxide in the atmosphere.
Dumping waste in landfill - when the waste decomposes it produces methane.
Agriculture - agricultural practices lead to the release of nitrogen oxides into the atmosphere.
What are droughts? Why are deserts not considered in drought?
when there is abnormally low rainfall for an extended period of time. Droughts can last from weeks to months and even years. A desert would not be considered in drought unless it had less rainfall than normal, for a long period of time.
What is subsidence?
Subsidence is when the ground beneath a building sinks, pulling the property’s foundations down with it. Subsistence usually occurs when the ground loses moisture and shrinks.
Explain one meteorological cause of drought.
A reduction in rainfall can cause drought because of changes in the
global atmospheric circulation where areas come under the influence
of high pressure
What is the hadley cell?
A large-scale atmospheric circulation pattern where:
Warm air rises near the equator, creating low pressure and heavy rainfall.
Air moves poleward at high altitudes, cools, and sinks near 30° N/S (subtropics), forming deserts.
Surface trade winds flow back toward the equator.
What is the ferrel cell?
A mid-latitude atmospheric circulation cell (between 30°–60° N/S) where:
Cold air sinks near 30° N/S (subtropical high-pressure zones).
Surface winds (Westerlies) blow toward the poles.
Warm air rises near 60° N/S (subpolar low pressure), creating stormy weather (UK WEATHER)
What is the Polar Cell?
The smallest and weakest atmospheric circulation cell, located between 60°–90° N/S, where:
Cold, dense air sinks at the poles (high pressure).
Surface polar easterlies blow toward mid-latitudes.
Air rises near 60° N/S (polar front), fueling storm systems.
What are trade winds
Steady, warm winds that blow from the subtropical high-pressure zones (30° N/S) toward the equator (0°) due to the Hadley Cell circulation.
What are ocean currents?
Large-scale, continuous movements of seawater driven by:
Wind (e.g., trade winds, westerlies).
Earth’s rotation (Coriolis effect).
Density differences (temperature & salinity).
How do ocean currents affect climate?
By transferring heat globally:
Warm currents (e.g., Gulf Stream) heat coastal regions (e.g., UK is warmer than Canada at same latitude).
Cold currents (e.g., California Current) cool coasts (e.g., San Francisco’s fog).
What is the jet stream?
A fast-flowing, narrow air current in the upper atmosphere (~9-16 km high), driven by:
Temperature contrasts (polar vs. tropical air).
Earth’s rotation (Coriolis effect).
Flows west-to-east in mid-latitudes at 200–300 km/h.
What is the gulf stream
A warm, powerful ocean current in the Atlantic:
Starts in the Gulf of Mexico → crosses Atlantic → warms NW Europe.
How does the gulf stream affect UK climate?
It delivers heat and moisture:
Winter: Keeps UK 5–8°C warmer than same-latitude areas (e.g., Canada’s Newfoundland).
Summer: Mild temperatures (less extreme heat).
Rainfall: Moist air from the Atlantic brings frequent rain (“UK drizzle”).
What are some natural causes of climate change?
Solar Variability
Volcanic Eruptions
Orbital Changes (Milankovitch Cycles)
How do volcanoes cause short-term cooling?
Sulfur dioxide (SO₂) erupts into the stratosphere forms aerosols that reflect sunlight.
How does the Sun influence climate naturally?
Variations in the intensity of solar radiation hitting the Earth may produce changes in global and regional climate.
What is eccentricity in Milankovitch cycles?
Changes in Earth’s orbit from circular to elliptical over ~100,000 years.
High eccentricity = more extreme seasonal differences.
Currently: Earth’s orbit is weakly elliptical (minimal impact).
How does obliquity affect climate?
Earth’s tilt varies between 22.1° and 24.5° over ~41,000 years (now: 23.5°).
Greater tilt = stronger seasons (hotter summers, colder winters).
Smaller tilt = milder seasons → favors ice sheet growth (cool summers = less melt).
What is precession, and how does it influence climate?
Earth’s axis wobbles like a top over ~26,000 years.
Changes which hemisphere faces the Sun during perihelion (closest orbit point).
Today: NH summer at perihelion → warmer winters.
In ~13,000 years: NH summer at aphelion (farther) → colder winters.
How do tree rings provide climate evidence?
Width: Wider rings = warm/wet years; narrow = cold/dry years
Density: Higher density = cooler temperatures
What does pollen reveal about past climates?
Different plant species = specific climate conditions
Preserved in lake sediments/peat bogs
Shows vegetation changes over millennia
What climate data comes from ice cores?
Air bubbles: Ancient atmospheric composition (CO₂, methane)
Oxygen isotopes: Temperature records
Dust layers: Dry/windy periods
What historical evidence shows climate change?
Paintings/diaries: Document glacier positions
Crop records: Harvest dates indicate temperatures
Ship logs: Storm frequency/sea ice extent
What is the natural greenhouse effect?
Natural process where greenhouse gases (GHGs) trap heat in Earth’s atmosphere
GHGs (CO₂, methane, water vapor) allow sunlight in but absorb outgoing infrared radiation
What is the enhanced greenhouse effect?
The additional warming of Earth’s surface caused by human activities that increase greenhouse gas (GHG) concentrations in the atmosphere beyond natural levels.
How does climate change affect humans?
Heat stress: More deadly heatwaves (e.g., 2022 European heatwave killed >60,000)
Disease spread: Mosquito-borne illnesses (malaria, dengue) expanding to new areas
Air pollution: Worse asthma/respiratory diseases from smog and wildfires
Malnutrition: Crop failures reducing food security
Sea level rise: Could displace 200 million by 2100
How does climate change affect the environment?
Ecosystem disruption – Species extinction (1M+ at risk), coral bleaching, and shifting habitats.
Ice melt – Arctic warming 3x faster than global avg; glaciers retreating, threatening freshwater supplies.
Extreme weather – More intense wildfires (e.g., Australia 2020), hurricanes, and droughts.
Ocean changes – Acidification (30% more acidic since 1800s), sea level rise (+3.7mm/year), and dead zones.
How does climate change affect sea level rise?
Thermal Expansion – Warmer oceans expand (accounts for ~50% of rise).
Ice Melt – Greenland/Antarctica losing 267 billion tons of ice yearly.
What is the impact of the North Atlantic Drift on the UK’s climate?
Temperature Moderation - Transports warm water from the Gulf Stream, making the UK significantly milder than other regions at similar latitudes (e.g., 5-8°C warmer than Newfoundland, Canada).
Winter Warming - Prevents extreme winter cold, giving southern England average January temperatures around 4-7°C compared to continental Europe’s sub-zero temperatures at similar latitudes.
Precipitation Influence - Contributes to the UK’s frequent rainfall by supplying moisture for Atlantic weather systems.
5 ANSWERS
How does the UK’s geographic location influence its climate?
Maritime Influence – Surrounded by oceans (Atlantic Ocean, North Sea) moderates temperatures, creating cool summers and mild winters compared to continental interiors at similar latitudes.
Prevailing Westerlies – Positioned in the mid-latitudes (50°–60°N) exposes the UK to moist, mild southwesterly winds from the Atlantic, bringing frequent rainfall.
North Atlantic Drift – Warm ocean current extends the Gulf Stream’s influence, raising winter temperatures significantly above the global average for its latitude.
Altitude –Air is forced to rise over the upland areas in the southwest and condense and fall as precipitation
Circulation cells- On the boundary of the Ferrel and Polar cells, Warm air and and Cold air meet forming depression and low pressure as it rises causing unsettled weather.
What is precipitation?
Precipitation is any form of water particles (liquid or solid) that fall from the atmosphere and reach Earth’s surface.
What are tropical cyclones?
Intense rotating storm systems that form over warm tropical oceans (26.5°C or warmer), with:
Winds ≥ 119 km/h (74 mph)
Low-pressure centers (“eyes”)
Spiral rainbands
How are cyclones formed?
Warm ocean water fuels evaporation → rising moist air.
Coriolis effect spins the system (absent at equator).
Low wind shear allows vertical development.
Progresses from disturbance → depression → storm → cyclone (winds ≥119 km/h).
Primary Impacts of Tropical Cyclones?
Destructive Winds (120–300+ km/h) – Rip roofs off buildings, uproot trees, and turn debris into projectiles.
Storm Surge – Sea level rise flooding coasts, the #1 cause of cyclone fatalities.
Torrential Rain – Triggers inland flooding and landslides
Secondary Impacts of Tropical Cyclones?
Infrastructure Collapse – Bridges, roads, and power lines destroyed
Water Contamination – Sewage overflow spreads diseases
Food Shortages – Crops/livestock wiped out
What is meteorological drought?
Defined by prolonged lack of precipitation (rain/snow) below regional averages.
Measured by:
Rainfall deficit (e.g., 30% below normal for 3+ months).
What is hydrological drought?
Defined by reduced water supply in rivers, lakes, reservoirs, and groundwater.
Caused by:
Long-term meteorological drought.
Over-extraction of water (e.g., agriculture).
Social impacts of droughts?
Water shortages – Rationing, conflicts over resources
Health risks – Poor sanitation → diseases (cholera, dysentery); heat-related illnesses.
Displacement – “Climate refugees” from rural areas
Food insecurity – Crop failures → malnutrition
Economic impacts of drought?
Agriculture – Crop/livestock losses
Energy – Hydropower decline.
Industry – Water-dependent sectors (e.g., textiles, brewing) face shutdowns.
Trade – Reduced exports
Environmental impacts of drought?
Habitat loss – Wetlands dry up .
Wildfires – Dry vegetation fuels fires.
Biodiversity decline – Species die-offs.
Land degradation – Desertification and soil erosion .
