Unit 3 - Our Changing Climate Flashcards
Factors of Weather
- Temperature
- Type and amount of precipitation
- Wind speed
- Relative humidity
- Atmospheric pressure
Weather
- Atmospheric conditions in a particular location over a short period of time
- Caused by interactions between water and air with energy from the Sun
Methods for Prediction of Weather
- Weather stations
- Weather balloons
- Aircraft
- Satellites
Climate
- Average of weather in region over long period of time
- Determined over weather measurements made over 30+ years
Climate system
Components that interact with each other to produce Earth’s climate
Energy from the Sun
- Almost all energy on Earth comes from sun
- Ultraviolet radiation (shorter wavelength; higher energy)
- Infrared (longer wavelength, lower energy)
- Visible light
Energy Absorbed by Earth
- 51% absorbed by land and oceans
- 19% absorbed by atmosphere and clouds
Outgoing Solar Radiation (30%)
- 6% reflected by atmosphere
- 20% reflected by clouds
- 4% reflected from Earth’s surface
Energy from the Sun (by location of the Earth)
- More intense near Earth’s equator because it receives energy more directly
- Less intense at the poles, since it hits Earth’s surface at an angle and spreads over a larger area
- Earth’s global temperature remains fairly constant
Atmosphere
- The layers of gases surrounding earth
- Reaches +100 km above Earth’s surface
- Part of atmosphere closest to Earth’s surface called the troposphere
Ozone in the Stratosphere
Ozone absorbs high energy UV radiation from Sun and prevents from reaching Earth’s surface
Hydrosphere
- Climate system including all water on and around Earth
- Solid water: Polar ice caps, icebergs
- Liquid water: lakes, streams, rivers, oceans, underground reservoirs
- Gaseous water: water vapour, clouds
Ozone in the Troposphere
Ozone doesn’t provide UV protection and can combine with car exhaust to produce photochemical smog
Photochemical Smog
Harmful to human health, buildings, plants and animals
After Evaporation
Transpiration
After Transpiration
Clouds Form
After Clouds Form
Precipitation
After Precipitation
Accumulation
Large Bodies of Water and Climate
- Affect climate of nearby regions by absorbing and storing thermal energy
- Regions near ocean or lake cooler in the summer and warmer in the winter than inland locations
Ice and Climate
- 2% of earth’s water frozen and can be found in Arctic sea ice, Glaciers, Permafrost and Mountaintops
- Surfaces covered in ice and snow have more albedo
Albedo
The ability for a surface to reflect light
Lithosphere
- Climate system made up of the rock, soil and minerals of Earth’s crust
- Mountains or cliffs can affect how air moves over an area
Troposphere Gases
78% nitrogen; 21% oxygen; 1% argon, carbon dioxide, helium, hydrogen and ozone traces
High Altitudes and Climate
- Atmospheric pressure lower because of less air pushing down
- Air rises and cools more easily, causing cooler temperatures
Photosynthesis
Plants take carbon dioxide and release oxygen
Cellular Respiration
Plants and animals take in oxygen and release carbon dioxide
Heat sink
Reservoir (ex: ocean) absorbing and storing thermal energy
Energy Transfer in Atmosphere
- Air is warmer than ocean, ocean absorbs energy from the air
- When the air is cooler than the ocean surface, the ocean releases energy back into the air
Convection currents
Created in air or other fluids when warm fluid (less dense) rises and cold fluid (more dense) sinks
Creation of clouds
- Air at the equator heats up and rises, which later cools and falls
- When air rises, a low pressure area is created, forming clouds
Thermohaline Circulation
Flow of water around world’s oceans by differences in water temperatures and salinity
Energy Transfer in Hydrosphere
- Water at poles cools and becomes more salty as ice forms
- Saltier, colder water sinks, causing another convection
Energy Transfer across Oceans
Ocean currents move water and heat carried around the world
Outgoing Lower-Energy Infrared Radiation
- 64% radiated to space from clouds, atmosphere and indirectly from Earth
- 6% radiated directly to space from Earth
Studying Clues to Past Climates
- Data climate is currently being kept on temperature, rainfall, precipitation
- Informal climate records kept through journals, paintings, farming records, oral histories
Proxy record
Information in tree rings, ice cores and fossils that can be measured to what climate was like in past
Ice Core Testing
- Measure air bubbles trapped in Greenland and Antarctica for thousands of years
- Ice at the bottom is 80 000+ years old
- Thin slices of ice tested for gases (CO2, CH4, N2O)
- Ice cores tested for oxygen isotopes (“lighter” oxygen found higher at lower temperatures)
Ice Cores: Additional Info Provided
Provide information on precipitation and volcanic eruptions as layers of dust are preserved
Tree Rings
- Thick tree rings formed in good growing conditions
- Warm, wet conditions = thick tree rings
- Cold, dry conditions = thin tree rings
- Can assemble data from living and dead trees to determine climate up to 10,000 years
Coral Reefs
Coral reefs grow at different rates depending on temperature of water
Rocks
- Pollen preserved in rock is indicator of plants species present at the location
- Can determine if there was warmer climate based on different species of plants
Ocean Sediment Clues to Climate
- Cores of sediment from ocean floor
- Fossils of marine organisms that lived in a warmer climate than today
Caves
Rock formations from stalactites (from the roof) and stalagmites (from the floor) are indirect evidence of precipitation patterns
Feedback Loops
- Positive feedback loop: Effect increases original cause
- Negative feedback loop: Effect decreases original cause
Low & High Clouds
- Low clouds involved in positive feedback loop between Earth’s temperature and water vapour.
- High clouds involved in negative feedback loop between temperature and water vapour.
Natural Changes in Climate
The result of changes in Earth’s Energy Balance
Plate Tectonics Basics
- Plates in constant motion, few cm per year
- Ocean floors continually moving, spreading from centre and sinking at edges
- Caused by convection currents fuelled by radioactive decay in Earth’s core
Continental Drift
Theory that parts of Earth’s crust slowly drift atop a liquid core (1912)
Plate Tectonics and Climate
- When continents move, ocean currents and wind patterns change, so heat transfer changes
- Uplifting of mountain ranges affect local and regional climates
Eccentricity Basics
From gravity of other planets, Earth’s orbit changes from circular to more elliptical over cycle of 100,000 years
Eccentricity Effects
- Doesn’t fully cause seasons (ex: Earth is furthest from sun in summer)
- Variation in distance from sun causes solar radiation received by Earth to vary
Eccentricity and Climate
- When orbit more elliptical, Earth receives more solar radiation when near the sun
- When orbit more circular, amount of radiation doesn’t vary much and seasons more equal in length
Earth’s Tilt - Basics
- Earth’s tilt on its axis changes 2.4˚ over 41,000 years
- Greater tilt, greater temperature differences between summer and winter
Earth’s Present Tilt
Currently tilt is 23.44˚ and decreasing (midway between extremes - 22.1 to 24.5˚)
Wobble (Precession of Tilt)
- Change in direction of axis of rotation or angle of tilt
- Earth is not perfect sphere, so it wobbles a little as it rotates
- Affects amount & intensity of solar energy received by Northern and Southern hemispheres at different times of year
Wobble and Climate Effects
- E.g. one hemisphere having contrasted seasons while other showing smaller temperature difference between seasons
- Occurs every 26,000 years and caused by pull of sun and moon acting on non-spherical shape of Earth
- Changes “North Star”
Effects of Long Term Natural Climate Variation
- Cause cycles of ice ages and interglacial periods
- Cause of the 100 000 year climate cycle.
Changes in Solar Energy
Amount of radiation produced by sun varies
Sunspot
Regular solar cycle that occurs every 11 years - if no. of sunspots is high, Sun is emitting more radiation
Volcanic Eruptions
- Aerosols (needed for cloud formation) spewed from volcanoes shade Earth’s surface - Earth cools for years up to decades
- Particles settle out or washed away with precipitation
- Volcanoes may cause temperature increase if lots of greenhouse gases emitted
Ocean Currents and Climate
- Changes to Earth’s thermohaline circulation can change climate
- As ice sheets melt, vast fresh water dumped into oceans
- Fresh water less dense than salty water, so it stays near surface, changing ocean currents
El Nino & La Nina
- Middle of South Pacific Ocean: periodic warming and cooling of seawater (El Nino and La Nina respectively)
- Can impact weather and climate change across North America
- Occurs every 3-8 years
Intro. Climate Change
Changes are being observed that have not happened for thousands of years
Rising Temperatures
- Earth’s average temperature increased from 1880 to present - most of warming occurred in last 50 years
- Small areas (over oceans) have seen temperature decreases
Melting Glaciers, Ice Sheets and Sea Ice
- Twice amount of ice in Greenland and Antarctica is melting in summer compared to 20 years ago
- Glaciers supply water to most rivers and lakes
Rising Sea Levels
- From 1993 to present, sea levels have risen twice speed as in previous 30 years
- Increase in sea levels due to melting of glaciers and thermal expansion
Changes in Severe Weather
- Intensity of heat waves and hurricanes increased
Changes in Precipitation
- Increase in precipitation as rain, less as snow
- W. North America experienced decrease in annual precipitation (resulting in drought and wildfires)
Changing Seasons
- Amt. of snow remaining on ground in winter decreases
- Decrease in # of very cold days
- Very cold days coming later in year and ending earlier in spring
Changes in Ecosystems
- Plants, trees, shrubs flowering earlier in the spring - results in longer allergy season
- Animals (ex. squirrels) breeding earlier in year & more often
- Animal and plant species migrating to higher altitudes and latitudes
Anthropogenic Definition
Human caused
