EARTHSC 2GG3 Lecture Notes - Lecture 13: Meteorology, Ultraviolet, Dengue Fever
18 Dec 2018
School
Department
Course
Professor
Climate Change
Friday, November 16, 2018 10:20 PM
Global Change and Earth System Science
• The effect of humans on Earth are extensive
• To recognize and modify the changes we have initiated, we need to understand how the Earth
works as a system
•Earth System Science
○ The aim is to study how the components of the system are linked on a global scale and how
these complex links affect life on Earth
• Atmosphere
• Oceans
• Land
• Biosphere
Climate and Weather
•Climate
○ Refers to the characteristic atmospheric conditions of a region over years or decades
○ Characterized by avg. temps and precipitation
•Weather
○ Refers to the atmospheric conditions of a region for days or weeks
Composition of the Atmosphere
•Permanent Gases
○ Concentrates of which do not change
○ Ex. Nitrogen, oxygen, argon
•Variable Gases
○ Concentrations of which vary in time and space
○ Ex. Carbon dioxide, water vapour, ozone, methane
• CO2 - drastic changes over small period of time
• Methane - highest concentration than ever seen before
• Much more effective at trapping energy than CO2
• Less concentrations so we don't think about it as much as CO2
Permanent Gases
○ Constitute about 99% by volume of all atmospheric gases
• Nitrogen, oxygen, argon
○ Nitrogen composes about 78% of the volume of all permanent gases
• Relatively unimportant to atmospheric dynamics
○ Oxygen composes about 21% of atmospheric gases by volume
Carbon Dioxide (CO2)
○ Makes up a v small % of the atmosphere
○ Released naturally by volcanic activity, plant and animal respiration, wildfires, and decay of
organic material
○ Removed through photosynthesis, chemical weathering, and absorption by sea water
• Weathering of limestone (some sort of chemical reaction)
• Suggestions: throw iron into the ocean for algae to capture CO2
○ It also enters the atmosphere through the burning of fossil fuels by people
• Increased greatly since the Industrial Revolution
Water Vapour (H2O)
○ Produced by the evaporation at Earth's surface
• May make more clouds
• May increase albedo of earth -> decrease
temp???
○ Geoengineering to try and manipulate this
• Albedo boats
○ Self driven boats into the ocean
○ Put salt ions in atmosphere
○ Condenses to form clouds and eventually returns to the surface as precipitation as part of
the hydrologic cycle
○ Air temperature is the primary control of the amount of water vapour in the atmosphere
• Warm air increases evaporation
Ozone (O3)
○ Found in small amounts in the stratosphere
○ Partially shields Earth from ultraviolet radiation from the sun
○ Smaller concentrations are found in the troposphere near the Earth's surface
• Produced by chemical reactions during the formation of smog
• Irritates lungs and eyes and aggravates respiratory problems
• (health issues)
○ Internationally discussed topic
Methane (CH4)
○ Major component of natural gas
○ Forms naturally by bacterial decay, and in the intestinal tracks of termites, cows and sheep
○ Anthropogenic sources include coal mines, oil wells, leaking natural gas pipelines, rice
paddies, landfills, and livestock
• Cows - gene splicing to reduce methane production
• From kangaroos - which produce no methane at all
○ Levels in the atmosphere have doubled since 1700
• Much more impactful per unit -> but v little in the atmosphere
• Still more methane now than ever before
Nitrogen Oxide Gases (NOx)
○ Sometimes referred to as nitrous oxides
○ Natural sources include microbiological processes in soils and oceans, wildfires, and lightning
strikes
○ Anthropogenic sources include automobiles, power plants, jet aircraft, and fertilizers
• Don't live within 0.5km of highway
○ Major impact to health, but minor impact to climate
• Contributes to global dimming -> so much smog?
Halocarbons
○ chemical compounds that contain carbon and halogen elements
○ Includes CFCs and are almost entirely anthropogenic
○ Used in industrial processes, firefighting, and as fumigants, refrigerants, and propellants
○ Contribute to warming of troposphere and ozone depletion in the stratosphere
Aerosols
○ Microscopic liquid and solid particles in the atmospheres
• The nuclei around which droplets condense to form clouds
• Will never get a cloud w/o aerosols
• Forms around salt ion -> sulfur dioxide
• Sticks to pieces and collects water
○ Natural sources of aerosols include desert dust, wildfires, sea spray, and volcanic eruptions
• Volcanic eruptions - natural sources
• 1991 - large Philippines volcano
• Global warming about 0.4 degrees for a few months
○ Anthropogenic sources include the burning of forests to clear land, and the consumption of
fossil fuels
Structure of the Atmosphere
• Much of the heat radiating from Earth's surface is absorbed in the troposphere
• Allow clouds to form
○ Increase albedo
Document Summary
Global change and earth system science: the effect of humans on earth are extensive, to recognize and modify the changes we have initiated, we need to understand how the earth works as a system, earth system science. The aim is to study how the components of the system are linked on a global scale and how these complex links affect life on earth: atmosphere, oceans, land, biosphere. Refers to the characteristic atmospheric conditions of a region over years or decades. Characterized by avg. temps and precipitation: weather. Refers to the atmospheric conditions of a region for days or weeks. Concentrations of which vary in time and space. Constitute about 99% by volume of all atmospheric gases: nitrogen, oxygen, argon. Nitrogen composes about 78% of the volume of all permanent gases: relatively unimportant to atmospheric dynamics. Oxygen composes about 21% of atmospheric gases by volume. Makes up a v small % of the atmosphere.
