Exam 3 Flashcards
Where is most freshwater?
glaciers, ice caps, underground aquifers
How much of Earth’s water is easily accessible to humans?
1 part in 10,000
What is 1/5th of Earth’s fresh water supply?
groundwater
How much of fresh water is surface water?
1%
What is the composition of ocean water?
96.5% H2O by mass, otherwise mostly salts
How much salt would here be if all water were evaporated from the oceans?
63-meter-thick layer
What is the longest mountain range in the world?
Mid-Atlantic Ridge (under the Atlantic ocean)
What could result from the slowing of thermohaline circulation?
Greenland would melt, giving the Atlantic less dense fresh water, and cooling Europe
El Niño
air pressure in the eastern Pacific decreases and in the western Pacific increases, weakening equatorial winds and sending warm water toward South America, suppressing upwelling along the Pacific Coast of the Americas, and shutting down a delivery of nutrients
How frequent are ENSO cycles?
every 2 to 8 years, though they may be increasing in frequency with climate change
What affects salinity in estuaries?
daily or seasonal variations in tides, fresh water runoff
How many people live within 160 k of the ocean?
2/3
What do mangroves help with?
protect shorelines from storm surges, filter pollutants, capture eroded soils to protect coral reefs
How many mangrove forests have been destroyed for development?
1/2
How tall and how much can kelp grow?
60 m tall, 45 cm per day
What do kelp forests help with?
shelter/food for invertebrates/fish, absorb wave energy to protect shorelines from erosion
Reef
underwater outcrop of rock/sand/other material
Corals
invertebrates related to sea anemones and jellyfish that remain attached to rocks/existing reefs to capture food with stinging tentacles or eat zooxanthellae
Zooxanthellae
make coral reefs colorful
What do coral reefs help with?
absorb wave energy to protect shorelines, host biodiversity (regions of high primary productivity)
What causes coral bleaching?
zooxanthellae die due to rising temperatures or more pollutants, depriving coral of nutrition
How much solar energy do the uppermost 10 ft of ocean absorb?
80% that reaches the surface
Where do ocean surface primary production and animal life concentrate?
areas of nutrient-rich upwelling
Detail the pelagic food chain
plankton at the base, then zooplankton, then fish/jellyfish/whales/free-swimming animals
How much of the world’s population are affected by water shortages?
2/3
How many of the 227 largest rivers have been strongly or moderately affected by human engineering?
60%
How does climate change affect rivers?
early runoff, intensifying droughts and flooding
How is annual freshwater distributed?
70% agriculture, 20% industry, 10% residential/municipal uses
How has irrigation changed in the last 50 years?
we now withdraw 70% more water for irrigation and have doubled the amount of land under irrigation
How much of water withdrawals for irrigation are predicted to be unsustainable?
roughly 15-35%
How many people rely on groundwater?
1/3 (99% of rural U.S. Americans)
What are consequences of over-extracted groundwater in coastal areas?
ocean saltwater intrudes on inland aquifers, causing coastal wells to take saline groundwater instead of freshwater
How can levees worsen flooding?
water accumulates, building up energy and causing overflow
How many dams greater than fifteen meters tall have humans built?
over 45,000, in over 140 mations
What is the biggest dam?
Three Gorges Dam on the Yangtze (186x2.3 km with a 616 km long reservoir)
What is the most common form of irrigation?
flood and furrow, 90% of irrigation, involving flooding fields with water (only 40% actually works on plants)
How many U.S. streams/rivers were reported in poor condition for aquatic life by the EPA in 2013?
55%
How many people are affected by disease from drinking water?
CDC estimates 4-23 million U.S. illnesses per year, U.N. estimates 1000 children killed per day
How long does plastic take to degrade at sea?
500-1000 years
Wastewater
sewage water, water from household appliances, water used in manufacturing/industrial cleaning processes, stormwater runoff
Sludge
solid material removed from purified water, sent to digesting vats, decomposed by microorganisms, then dried and disposed of in landfills/incinerated/used as crop fertilizer
How many marine fish populations are fully or over exploited?
60% fully, 30% over
How many commercially harvested fish were estimated in 2016 by the NOAA to have been captured unintentionally?
11%
How many large-bodied fish/sharks remain, largely due to fishing?
1/10
How many of the world’s oceans were MPAs in 2019
7.6%
How much excess CO2 from humans have the oceans soaked up?
about 1/3
What availability of carbonate ions is needed for reefs and shells to continue growing?
over 200 micromoles per kilogram
What is the composition of the atmosphere?
78% nitrogen, 21% oxygen, 1% argon and other gases
What is the concentration of water vapor in the atmosphere?
varies from 0% to 4%
Why does the stratosphere warm with altitude?
ozone and oxygen absorb ultraviolet radiation
What are the layers of the atmosphere?
Troposphere (avg. 11 km high, 3/4 of the atmosphere’s mass), [tropopause], stratosphere, mesosphere (extends to 500 km, temperature decreases with altitude, meteors burn up on entry), exosphere
How much solar energy is absorbed by the Earth’s atmosphere and surface?
70%, the rest reflected into space
How do temperature and humidity vary with altitude?
warmer/moister near the surface
How many people are estimated by the WHO to die early from pollution-related health issues?
4.2 million
Is ozone a primary or secondary pollutant?
secondary
How do residence times differentiate pollutants in their impact?
short residence times have localized, short-term impacts; long residence times have global, long-term impacts
What is the primary source of carbon monoxide?
vehicles/engines
What is the primary source of sulfur dioxide?
coal combustion for electricity/industry (which returns to the Earth in acid deposition as sulfur trioxide [SO3] or sulfuric acid [S2SO4])
What is the primary source of nitrogen oxide in the U.S.?
reaction of nitrogen and oxygen at high temperatures during vehicle combustion
Where do VOCs come from?
solvents, industrial processes, household chemicals, paints, plastics, consumer items
Where do most PM10 particles (10 microns in diameter) come from?
road dust
Where do most PM2.5 particles (2.5 microns in diameter) come from?
combustion
Name the criteria pollutants
carbon monoxide, sulfur dioxide, particulate matter, lead, nitrogen dioxide, tropospheric ozone (which most frequently exceeds EPA standards)
Where was the world’s worst industrial smog event, and how many died?
London, England (1952) due to a high-pressure system, killing 4000 people
What are the biggest contributors to air pollution?
carbon dioxide/greenhouse gases
What effect do chlorofluorocarbons have on the stratosphere?
linger for at least a century; one free chlorine atom can catalyze 100,000 ozone molecules
When is the ozone hole expected to recover?
2060 (many CFCs emitted to the troposphere have not yet reached the stratosphere)
How does acid deposition hurt plants?
replace calcium/magnesium/potassium ions in topsoil which can make them inaccessible to plant roots and convert aluminum/zinc/mercury/copper to soluble forms which can damage roots
How does acid deposition affect fish?
kills them by affecting their gills, salt balance, water balance, breathing, and circulation
What is the primary pollutant that poses an indoor health risk?
cigarette smoke
What type of radiation is emitted from the surface after solar radiation is absorbed?
infrared radiation, which has longer wavelengths than visible light
Which types of gases tend to absorb infrared?
atmospheric gases with three or more atoms per molecule (like greenhouse gases)
What is the most abundant greenhouse gas from human activity?
carbon dioxide
How have atmospheric concentrations of carbon dioxide changed since the late 1700s?
278 ppm to 400 ppm (higher than in 20 million years)
How much radiative forcing does Earth naturally receive/give off?
340 W/m^2, and now receives 2.3 W/m^2 more due to climate change
Glaciation
global surface temperatures drop and ice sheets expand from the poles
What do IPCC Assessment Reports cover?
summarize trends in climate/ice, predict future trends, address impacts and strategies
What do U.S. Global Change Research Program Climate Assessments cover?
coordinate federal climate research
How much have average surface temperatures changed in the last century?
+1.1 degree Celsius
How has precipitation changed and why?
+2% because a warmer atmosphere speeds evaporation
How has the frequency of extreme weather events changed since 1970?
tripled
Polar vortex
massive low-pressure system, in which cold air swirls around and can be released by the weakening of the jet stream
How much excess global warming energy have the oceans absorbed and what affect does this have on weather events?
90%, stronger hurricanes
How many people live in regions that use mountain meltwater (like from glaciers)?
1/6
How much have average sea levels risen in the last 140 years?
26 cm
How much would the sea rise if all ice melted?
65 m
List examples of mitigation
improve energy efficiency, switch to clean/renewable sources, preserve/restore forests, recover landfill gas, promote sustainable farm practices
List examples of adaptation
install pump systems, erect seawalls, restrict coastal development, adjust farming practices, modify water management practices
How are U.S. CO2 emissions distributed?
over 35% transportation, 35% electricity
How much of global CO2 emissions come from agriculture?
14.5%
Project Drawdown
76 strategies proposed by Paul Hawken in 2014 to bring about the point where atmospheric gases peak and decline; this could, in 30 years, pull 1.0-6.0 trillion tons of greenhouse gases out of the air and save $16-29 trillion
Paris Agreement
nations agreed to limit global temperature increase to 2.0 degrees C and keep the increase below 1.5 degrees C compared with pre-industrial levels; effective because each nation brought their own strategies for reducing emissions
