Quiz 6 Flashcards
Climate change
overall trend of entire earth’s surface toward a different average state
Hurricane Sandy and global warming
Scientists don’t believe it was directly caused by GW but by some contributing factors
As air pressure decreases
Air rises, cools, condenses
As air pressure increases
air sinks, warm, moisture evaporates
Specific humidity
Total amount of water vapor in air
Relative humidity
% is measure of how close air is to saturation humidity
Humidity saturation point
where vapor condenses
Evaporation and warmer climate
Specific humidity will increase but relative humidity will stay about the same
Cyclonic Storms
Form from pressure differentials, large low pressure area near earth’s surface. Winds generated by mixing of cold dry air and warm wet air- Release of large amounts of latent heat as moist air is carried upward and condenses
Where do storms form?
Hurricanes - Atlantic/E. Pacific Oceans
Typhoons - Form in W. Pacific
Cyclones - S. Hemisphere or Indian Ocean
For cyclones sea surface temps must be
Warm enough
El Nino Southern Oscillation Cycle
Fluncuations in temp. between the ocean and atmosphere in east-central Equatorial Pacific.
- 9-12 months, typically
- Warm phase in S. Am/CA
- droughts in Indonesia/Australia
ENSO cold phase
Unusually cold ocean temps in eastern tropical pacific. Warm water near surface blown to west. Cold water hampers formation of clouds/storms, drought to SW US
Droughts
defined by: amount of rainfall, amount of water evaporated, amount stored in soil
____ atmosphere can hold more moisture, existing patterns of moisture transport intensified
Warmer
Sahel Region of Africa
Transition zone between tropical forest to south and Sahara desert to North.
Jul. to Sept. - Rains move in during W. African monsoon; Semi-nomadic people move herds from North to South during dry oeruid, Permanent settlements in fertile areas
Drought in Sahel
Two spikes in severity of droughts from 1960s-1980s, famine killed 100,000, drought occurred simultaneously with other climactic changes
^warming of sea temps
Predicted Future Drying
Long term predications of climate change linked to drier conditions in US South, midwest, South Euro-Meditaranian, SE asia, Australia, most of Africa, Brazil, Chile
Effect of aerosols
Sunlight necessary for rainfall, heats ocean, water evaporates, falls as rain. Aerosols reduce sunlight
Floods
Develop very quickly in response to extremely intensive rainfall,
IPCC - extreme flooding most widespread risk to human settlements from both increased rainfall and sea level rise. River, coastal urban areas affected.
Damages crops, fosters spread of disease, overwhelm water treatment, landslides, erosion
Heat Waves
As planet gets warmer there will be more heat waves of greater intensity, associated with semi-stationary domes of high pressure-clear skies, light winds, warm air prolong hot conditions at surface
High pressure associated with heat waves = higher summer nighttime minimums, daytime minimums- predicted to increase as greenhouse gases increase
Effects of heat waves
Heat stroke, death, power outages, wildfires, physical damage- roads, water lines, power transformers detonating, agricultural damage
Warming and CO2
Warming = increasing release of CO2
Cooling and CO2
=increased capture of CO2
Insolation
Incoming solar radiation
Relationship of light energy and wavelength
inversely related
most energy is in what light range
Visible
Function of Ozone
absorbs UV light radiation due to structure
Simpler gases and light
O2 and N2 do not reaction with infrared or UV light
Why can we see the stars
No atmosphere gases react with visible light
Greenhouse gases
manmade, natural, contribute to greenhouse effect, most abundant component = water vapor, interact significantly with infrared heat radiation emitted from Earth’s surface- Allows sun’s energy to pass through but inhibits escape of heat back into space
Greatest contributors to greenhouse gas emissions
Burning fossil fuels
Transportation
Industrial processes
Land use changes- Deforestation, Agriculture
Natural sources of CO2 how many times greater due to human activity
20x
Levels increasing about how much per year
.5%
Methane
Naturally occurring, produced by bacteria when decamping plant and animal material
Human related sources - Agriculture, Livestock, Landfills, Mining, Pipeline leakage
Nitrous oxide N2O
Natural sources - soil denitrification, burning organic matter
Human sources - use of synthetic and organic fertilizers, production of nitrogen-fixing crops, application of manure, fossil fuel combustion, sewage management
CFCs
No natural sources, have more powerful greenhouse gas effect than CO2
Global Warming Potential
Measure of how much a gas is estimated to contribute to the greenhouse effect
___ accounts for 2/3 of global warming
CO2
Positive radioactive forcings
Cause warming of climate
Negative radioactive forcings
Cause cooling of climate
Climate response to radiative forcings
Changes in global mean near-surface air temps resulting from a sustaining doubling of atmosphere CO2 concentrations
Positive feedback - water vapor
Warm air can hold more water vapor than cold, greenhouse gases = warming = increase in vapor concentration, water vapor absorbs radiating heat from surface, increases warming of atmosphere/surface
Why are we worried about CO2 concentrations when water vapor has a greater effect on global temps
Water vapor is not a radiative forcing external to system, CO2 is pumped into atmosphere regardless of surface temp, Water vapor highly dependent on air temperature - relative humidity stays constant
Polar Amplification
Key role in why arctic is warming faster than rest of Earth, warming melts ice, replaced by dark sea, land = absorbs more energy
Solar heat absorbed by oceans in summer in summer more easily transferred to atm. In winter atmospheric layer in arctic is thinner
Climate feedback - cloud (pos. and neg.)
Absorb outgoing heat radiation - positive effect
Highly reflective - negative effect
low thick clouds = cooling effect
Carbon Cycle
Cycling of CO2, short term cycles - photosynthesis, respiration, burning, decomposition, ocean uptake and release
Long term - sedimentation in oceans, land; volcanic release, weathering
Rapid changes to carbon cycle
Burning coal, oil, natural gas- Releases CO2 in atm. much faster than natural release
burning of forests
Ocean uptake of carbon…
enhances warming
increase in CO2 and photosynthesis
increase in CO2=increase in photosynthesis
Effects of Aerosols
Natural sources - soil and dust particles, pollen, volcanic eruptions, evaporated sea salt
Anthropogenic sourcesL sulfate oxides of nitrogen, black carbon
Aerosols- Oxides of nitrogen
Forms when combustion initiates reactions with atmospheric nitrogen and oxygen
Produces nitrogen oxide
Aerosols - Black carbon
Products of incomplete combustion - soot, charcoal, char, carried in the sky by hot air from combustion, return to earth through rain or settlings as dust
Potential climate forcing agent- second largest to CO2
Twofold effect of black soot on ice and snow
Dark particles absorb heat energy: Increases melt of snow, soot becomes more concentrated on snow surface
Darkens surface and reduce albedo
Indirect effects of aerosols
Cloud formation - naturally occurs when water droplets form air borne particulates - pollen, dust
Water droplets reflect sunlight back into space = cooling effect
Aircraft contrails
Implicated in dimming but could not be tested because of constant air traffic, shutdown of air travel after 9/11 - increase in air temps
Reverse of global dimming
Shift from dimming to brightening trend in 1990 due to decrease in air pollution
Is it possible to prove climate change is due to anthropogenic greenhouse gases
Many hypotheses can be put forth to explain an observed phenomenon or experimental results. Some are incorrect some are supported. Can only prove a hypothesis is incorrect or inadequate
Correct predictions of climate change
Sea levels should rise as ice melts and warmer seawater expands
Stratosphere should cool in response to increasing levels of greenhouse gases
Warming in arctic = enhanced due to ice melt, energy absorption of exposed seawater
Trend skeptics
Deny any trend of global warming
How do we know climate change is human caused
Hindcasting - reproduce observed past changes in climate models
Attribution skeptics
Warming is occurring but can’t attribute to human activities
Impact skeptics
Warming is occurring but impact will be mostly positive
Pessimistic believer
Believes human connection, may favor GG reductions but also believes action is futile or too expensive
Philosophical
not denying but believe issue is overhyped
Myth Makers
Tobacco roots, Media giving “equal time” to both sides, carbon lobby
