Enviro Ch 15 Climate Change
How much solar energy reaches the earth's surface
-1/2 -some of this energy is reflected by bright surfaces (snow and ice) -rest is absorbed by earth's surface and water
Of the solar energy that reaches the outer atmosphere...
-1/4 is reflected by clouds and atmospheric gases -1/4 is absorbed by CO2, water vapor, ozone, methane, and other gases
Kyoto Protocol
-1997 meeting where countries voluntarily set their own targets for reducing emissions of CO2, CH4, N2O, and fluorine gases -not successful in reducing overall global emissions -many countries (esp europe) met or exceeded argent reduction of 5-10% below 1990 emissions by 2012 -poor nations like India and China ere exempt so that they could expand Econ and improve living standards -US declined to sign agreement
Sir Nicholas Stern
-2006: announced that if we don't act soon, climate change will cost 5% of global GDP each year; damage could equal 20% of annual global Econ -2009: reducing GHG emissions now would cost only 1% of annual global GDP; energy production would have to be 80% decarbonized by 2050 to stabilize global climate -many could become refugees
Methane (CH4)
-2nd most important greenhouse gas -accumulates faster than CO2 -produced when plant matter decays in oxygen-free conditions (when oxygen is abundant, much CO2 is produced) -released from natural gas wells -rice paddies, ruminant animals (cows burping)
Nitrous Oxide (N20)
-8% of greenhouse gases -agriculture, plant decay, vehicle engines, denitrification,
How has Germany reduced GHG emissions?
-80% renewable energy by 2020 -switch from coal to wind, solar, and gas
From ices cores, we know that
-CO2 cons have varied 180-330 ppm in past 800,000 years -world climate can change abruptly
How do scientists respond to this? "The climate has changed before, so this is nothing new"
-CO2 level is 400 ppm -past records show that before it was 180-300 ppm
When is sun most intense
-Dec-Jan: south of equator -June-July: north of equator -whenever sun shines most directly, evaporation and convection currents (and rain and thunderstorms) are strong
Troposphere
-Heated by the warmed earth surface; convection cells result as warmed air rises -layer of air adjacent to earth's surface -air is in constant motion and redistributes heat and moisture around the globe -air absorbs energy from sun-warmed earth's surface, and from moisture evaporating from oceans -convection currents -depth is 18 km over equator (heating and convection are intense) to 8 km over poles (air is cold and dense) -contains 75% of total mass of atmosphere
Most solar energy is...
-Intense, high energy light with short wavelengths near the ultraviolet and visible spectrum -short wavelengths pass easily though the atmosphere -some energy reflected back due to albedo -rest of energy is absorbed and converted to heat (lower intensity, longer wavelength radiation) -> CO2 and water vapor absorb this ad rerelease it in lower atmosphere -> this heats up lower atmosphere (w/out it, earth would be 18 celsius colder and no liquid water)
Atmosphere
-Layered, with more massive molecules near the ground surface -retains solar heat, protects us from deadly radiation from space, distributes water -made up of gas molecules
Water has a...
-Low albedo and is efficient at absorbing energy and storing it as heat -increasing open water poles worry climatologists
How do scientists respond to this? "A comfortable lifestyle equines high CO2 output"
-Northern Europeans produce less than half of CO2 than North Americans, and their have higher standards of living
Ozone (O3)
-Pollutant near earth's surface -in stratosphere, it absorbs wavelengths of ultraviolet solar radiation (UV-B) -protects life on earth's surface
Warm front
-advancing air mass is warmer than surrounding air -advancing warmer font slides up over cooler air masses (warm air is less dense than cold), making a long, wedge shaped profile with clouds and precipitation -highest layers of clouds are called wispy cirrus (mare's tail) and are made of ice crystals -warm front can bring drizzle and cloudy skies
Freon
-air pollutant that was used in refrigerators and bromine compounds and used as in pesticides -deplete stratospheric ozone (esp. Antartica) -let UV radiation reach earth's surface
How do scientists respond to this? "There is no alternative to current energy systems"
-alternative energy and conservation can reduce our fossil fuel consumption to safe levels -new wind and solar electricity is cheaper than new oil or gas-burning power plants -also created new markets and jobs
Why does air bend in diff directions in n and s hemisohere
-art rotates in eastward directions as winds move above the surface
How has New Zealand reduced GHG emissions?
-carbon neutral by 2025 -wind and geothermal energy carbon capture on farms
Financial strategies
-carbon taxes and markers for trading carbon emission credits -this has reduced consumption and fund renewable energy -cap and trade for carbon
Volcanic emissions added what to the atmosphere
-carbon, nitrogen, oxygen, sulfur, and other elements
Gulf Stream
-carries warm salty Caribbean water north past Canada to Northern Europe -keeps Europe much warmer than it should be for its latitude -as water passes Iceland and Scandinavia, water cools and evaporates, becomes more dense, sinks down-> crates a strong, deep, southward currents (ocean conveyor system)
How can we reduce methane emissions
-changing flooding schedules and fertilization techniques -reduce gas pipeline leaks -eat less beef
Ice cores
-contain CO2 and oxygen isotopes used to reconstruct past temps and atmospheric composition -small amounts of air is trapped in snow layers when it snows and air bubbled remain (sample of atmosphere of when it was sealed off)
Coriolis effect
-describes the apparent curving of winds -merry go round example
Milankovitch cycles
-drive long term climate changes -influence how close the earth is to the sun and control how much of the sun's energy we receive
What creates seasons
-earth orbits sun, tilt of axis makes seasons
El Niño southern oscillation (ENSO)
-el niño + La Niña -core is a pool of warm surface water in Pacific Ocean that goes between Indonesia and s. America -trade winds usually push down ocean surface surrender westward -> air heated-> air rises making strong convection cells -> rains in tropical rainforests in n. Australia an s.e. Asia -trade winds help move ocean currents West -every 3-5 years, convection currents weaken and warm water goes to Peru and CA
How do scientists respond to this? "Alternative energy requires subsidies"
-fossil fuels receive more subsidies in tax incentive than alternatives do ($550 billion vs $120 billion) -shifting to wind, solar, and conservation is more economical and profitable
How do scientists respond to this? "Climate scientists have gaps in their knowledge and have made errors in the past"
-gaps and uncertainties in climate data are minute compared to evident trends -no fraud data
Surfaces that reflect energy...
-have a high albedo (reflectivity) -appear bright cause they reflect energy
Polar cells and Ferrell cells
-have less intense hearing and less vigorous circulation than the equatorial Hadley cells
Thermosphere
-heated layer that begins at 80 km -highly ionized gases -hated by a steady flow of high energy solar and cosmic radiation -intense pulses of high energy radiation cause electrically charged particles (ions) to glow (northern and southern lights)
When does air rise?
-in convection currents where solar heating in intense (like the equator) -when two air masses collide and one must rise over the other -when it encounters mountains -when the air is moist, condensation and rainfall is likely as air I'd lifeted
How can we cut a gigaton from the 7 to achieve stabilization?
-increase fuel econ in cars from 30 to 60 mpg -reduce reliance on cars (more public transit) and cut driving average from 10,000 mi to 5000 or year -better insulation and efficient appliances in houses and buildings -increased efficiency in coal power plants -capturing and storing carbon a tower plants, improving plant operation, slashing reliance on coal -alternative energy, no deforestation, reduce soil loss
Carbon capture and injection
-inject CO2 under sea floor increases pressure on oil reservoirs and enhances oil recovery -saves $ cause companies would have to pay $50 per ton tax on its emissions
Pacala and Socolow
-introduced wedge analysis -efficient vehicles, buildings, power plants, alternative fuels can solve problems -3 major trajectories in carbon emissions
How do scientists respond to this? "Reducing climate change requires abandoning our current way of life"
-it requires using diff energy -use wind, solar, natural gas instead of coal -reducing coal will also reduced financial costs of pollution damage to health vegetation
Paris Climate Agreement 2015
-keep global average temp increase below 2 Celsius (preferably 1.5 Celsius) -zero carbon emissions is a global goal (avoid worsening climate effects) -each participating country establishes voluntary emission reduction goals (goals must be publicly visible) -plan must be revised every 5 years -climate finance: advanced economies donate $100 billion per year to "green carbon fund" to support low-carbon development in emerging Economies -195 countries
The earth's earliest atmosphere was made up of...
-lightweight hydrogen and helium (which overtime diffused into space)
Surfaces that absorb energy...
-low albedo and appear dark -black soil, pavement, open water -heat absorbing surface, evaporate water, provide energy for photosynthesis in plants
Absorbed energy is gradually reemitted as...
-lower quality heat energy (complies with second law of thermodynamics)
Aerosols
-minute particles and liquid droplets that are suspended in the air -atmospheric aerosols are important in capturing, distributing, or reflecting energy
ENSO and climate change
-more droughts and floods due to more climate change -pool of warm water is warming and expanding Contrast: -increased clouds -> more albedo -convection currents made by storm can pump heat into stratosphere -cooling effect
Monsoons
-most regular seasonal rains -in India and Bangladesh, monsoon rains come when seasonal winds blow hot, mid air from Indian Ocean -hot land surface makes strong convention currents that lift this air-> heavy rains -when rising air reaches Himalayas, it rises more-> more rainfall
Incoming solar radiation (insulation) is much stronger...
-near the equator than at high latitudes -energy isn't evenly distributed
End of atmosphere
-no boundary marks the end -density of gas molecules decreases with distance from the earth until it becomes indistinguishable
The Coriolis effect produces...
-on global scale: predictable weather patterns and currents -on regional scale: produces "cyclonic" winds
Observatory in Maura Kea in Hawaii
-one of the first places to show human impacts on CO2 -1957 -CO2 conc were increasing about 0.5 per year -Charles David Keeling's graph
How do scientists respond to this? "We had cool temps and snowstorms last year, not heat and drought"
-regional diff in temp and precipitation trends are predicted by climate models -US is expected to see wetter, warmer winters and drier, hotter summers
Greenhouse effect
-retention of long wave terrestrial energy in the atmosphere -atmosphere lets sunlight travel through while trapping heat inside -needed for life on earth
Weather
-seen in lowest 10-12 km of atmosphere -short-lived and local patterns of temp and moisture that result from this circulation
Intergovernmental Panel on Climate Change (IPCC)
-since 1998, it has brought together scientists and gov. reps. from 130 countries to review scientific evidence on the chases and effects of climate change -finding that there is a 90% probability that climate change is caused from human activities -some changes were 99% likely to be anthropogenic (human-caused)
Peat
-soggy, semidecayed plant matter accumulated overtime across the tundra in Canada and Siberia -as if thaws and dries, it oxidizes and decays (release CH4 and CO2)
How do scientists respond to this? "Natural changed such as solar variation can explain observed warming"
-solar input fluctuates, but the changes are slight -these and other natural changes don't coincide with the direction of changes in temp or warming
Fourth IPCC report
-stated that preventing CO2 doubling and stabilizing the world climate would cost 0.12% of annual global GDP per year -compare this with Stern
Tornadoes
-swirling funnel clouds that form over land -cyclonic storm -generate on American Great Plains by giant supercell frontal systems where strong, dry air cold fronts from Canada collide with warm, humid air moving north from Gulf of Mexico
Since ice shelves float...
-they don't make sea level rise -BUT ice melting ice caps and glaciers contribute 1 mm per year to sea level rise
Condensation nuclei
-tiny particles of smoke dust, sea salts, spores, and volcanic ash -form a surface on which water molecules can begin to coalesce -without them, even supercooled vapor can remain in gaseous form
Jet streams
-top of troposphere -hurricane-force winds that circle earth -these winds follow a path approximately where the vertical convection currents (Hadley and Ferrell cells) meet -affect weather patterns -deeply wavy curvy jet-streams can bring cold polar temp far south (colder period than normal) -warming climate may lead to waiver jet streams
Greenhouse gases
-trace gases that capture the long-wavelength heat energy from the earth's surface -water vapor is most abundant -CO2, CH4 (methane), N2O (nitrous oxide), fluorine gases
Stratosphere
-troposphere to 50 km -more dilute than troposphere, but similar composition, but almost has 0 water vapor and 1000x more ozone (O3) -calm because warm layers lie above cool layers (little mixing)
How has Britain reduced GHG emissions?
-vow to reduce by 60% by 2050 -substitute natural gas for coal (energy efficiency in home and industry) -raise gasoline tax -decarbonize Britain -revenue neutral carbon levy
Pacific Decadel Oscillation (PDO)
-warm water that moves back and forth across N. pacific every 39 years -1977-1997: surface water temp in middle and western n. Pacific Ocean were cooler (water in w. US were warmer) -much salmon in alaska -1997: water got cooler and salmon returned to normal
Ultraviolet solar radiation (UV-B)
-warms upper stratosphere, so temp increases with elevation -damages living tissues, causes skin cancer, genetic mutations, crop failures
Cold front
-when cooler air pushes away warmer air -cold air of cold front hugs the ground and pushes under the lighter, warmer air as it advances -as warmer air goes up, it cools, and its water vapor condenses to water droplets or ice crystals -air masses near ground move slow cause of friction and turbulence near ground surface (upper layers of moving air move ahead of lower layers) -DNA form strong convective currents as their push warmer air up-> strong winds and thunderstorms
Where does high pressure occur?
-where convection currents sink -where air sinks after flowing over mountains
Cyclonic winds
-wind movements controlled by the earth's spin -spiral clockwise out of an area of high pressure (sinking air) in the N. hemisohere -spiral counterclockwise into low pressure zone cause air is moving up
Over the last century, the average floral temp has climbed up how much
0.9 Celsius
Pacala and Socolow's 3 major trajectories in carbon emissions
1) "buisness as usual" (current pattern of CO2): tripling of CO2 by 2100, temp increase of 5 Celsius, sea level rise of 0.5-1 m 2) "stabilization scenario" (prevent further increases in CO2 emissions): double CO2 in atmosphere by 2100, temp increase of 2-3 Celsius, sea level rises 29-50 cm 3) declining CO2 emissions could result from new energy sources and better land management
Keeling's graph showed some patterns
1) annual variation in CO2 concentrations: every May, CO2 levels drop slightly as plant growth captures CO2 in photosynthesis; during winter, levels rise again as respiration releases CO2 2) CO2 levels are rising more than 2 ppm each year
Greatest sources of CO2 ranked
1) burning fossil fuels 2) deforestation 3) cement production
Three arguments on why climate change is caused by humans
1) climate change corresponds to changes in human activities (human pop growth, fossil fuel consumption) 2) current rates of change are higher (look at ice cores, etc)
The stern review recommends 4 key elements for combating climate change
1) emissions trading to promote cost-effective emissions reductions 2) technology sharing that would double research investment in clean-energy tech and accelerate the spread of that tech to developing countries 3) reduction of deforestation (quick and highly cost-effective war to reduce emissions) 4) helping poorer countries by honoring pledges for development assistance to adapt to climate change
Effects of climate change
1) summer heat waves-> forest fires; precipitation-> more storms and flooding and less rainfall in other places 2) droughts expanded (killing people, agriculture, trees) 3) regions near the poles have warmed faster than rest of world (permafrost melting, city damage, beetle infestations, hectares of pine and spruce dying) 4) arctic sea is half as thick than 30 and area decreased 1 mil km^2 (polar bears need ice to hunt seals) 5) ice shelves in Antarctic peninsula are breaking up and disappearing (penguin pop declining) 6) glaciers disappearing 7) sea level rising (15-20 cm in past century) (thermal expansion of sea water and melting glaciers) 8) animals are breeding earlier and movie to new land 9) coral reefs are bleaching 10) ocean reefs are absorbing CO2 and storing heat (postpone impacts of GHG emission-slowing global warming) (CO2 acidifying ocean)
How much of the world's population now live in areas that would be flooded if all of Greenland's ice were to melt?
1/3
Climate data show that the past...
30 years were the warmest period in 1300 years
How much does carbon dioxide contribute to human caused climate impacts
75%
Silver bullet
A technology that will fix the problem all at once -many politicians hope for one -ex) nuclear fusion, space based solar energy, etc.
Where air rises in convection cell currents...
Air pressure at the surface is low
Where air is sinking...
Air pressure is high
The northern and southern lights are also called
Aurora borealis and aurora australis
Front
Boundary between two air masses of diff temp and density
Wedge analysis
Breaking down a large problem into smaller, bite-sized pieces -calculate the contribution of each edge, add them up, see the magnitude of their collective effect, and decided whether it's worth moving forward
La Niña
Brings hot, dry weather to CA and midwestern states
Gyres
Carry water broth and south, redistributing heat from low latitudes to high latitudes
In northern hemisphere, wind bends...
Clockwise (right)
Anytime air is rising...
Clouds, rain, or snow may from
In southern hemisphere, wind bends...
Counterclockwise (left)
The atmosphere has four distinct zones of contrasting temp, which result from...
Differences in absorption of solar energy -troposphere, stratosphere, mesosphere, thermosphere
Keeling curve
Documents changing CO2 concentrations
Weather after the cold front passes is...
Dry, clear, invigorating
Sun shine at equator, mid-latitudes, and poles
Equator: sunshines straight overhead, solar heating and water evaporation is intense Mid-latitudes: angle of sun is lower, heating is less intense Poles: sun shines low on the horizon much of the year and little heat is available for warming the ground to evaporating water
In cold years, water molecules with slightly lighter oxygen atoms...
Evaporate more easily than water with heavier isotopes
Incoming solar energy can also...
Evaporate water -each gram of evaporating water absorbs 580 calories of energy as it transforms from liquid to gas (latent heat) -rising air cools with altitude and water vapor condenses to liquid droplets; as it condenses, each gram of water releases 580 calories of heat -moving water vapor men's that latent heat can warm and accelerate rising air currents in diff locations
Solar energy absorbed by the ground...
Eventually re-radiates as long wave infrared energy, and this energy warm the lowest layers of airs
Atmospheric circulation redistributes...
Heat and moisture
Atmospheric circulation carried a great deal of...
Heat and moisture from warm humid places to colder, drier places
The composition of the atmosphere influences...
How much heat energy is stored
In warm, low-latitude Atlantic, cyclonic storms are called...
Hurricanes
If we don't reduce our carbon output in the next few years, we will lose...
Ice caps and permafrost -increase of 5-7 celsius within the next cent -rising sea levels of 1 m or more by 2100
Climate
Long-term patterns of temp and precipitation
Ferrell cells
Mid-latitude cells
Water vapor concentrations vary from...
Near 0 to 4 percent -depends on air temp and available moisture
Where is circulation more vigorous
Near the equator than at high latitudes cause of the more intense heating from sun
Clean, dry air is made of
Nitrogen and oxygen
Which regions are warming most rapidly
Polar regions and continental interiors
Greater air temp differences can cause more...
Powerful storms -why most tornadoes occur in spring (arctic cold fronts reach far south to warming plains)
Main reason for variable climate
Region of most intense solar heating evaporation change during year -earth's axis of rotation is at an angle
Deforestation
Releases carbon stored in standing trees and organic material in the exposed soil oxidizes and decays, producing more CO2 and CH4
If water vapor is abundant, rising and cooling air...
Releases latent heat energy
How has Denmark reduced GHG emissions?
-40% of energy from windmills -"no regrets" policy (even if climate isn't stabilized, many of these steps save money, conserve resources) -use nuclear power (doesn't produce GHG)
Developing regions are helping by...
-India and Bangladesh are in in "green bonds" that support renewable energy and make many new jobs
Mesosphere
-above stratosphere -temp diminishes -middle layer
Why do we still debate climate change evidence?
-change might be threatening (rather ignore) -lack of info
Coral reef bleaching
-coral reefs are dying as they lose their photosynthetic algae -coral reefs house many sea organisms
El Niño
-example of ocean-atmosphere oscillation -coastal waters become very cool
Where does air sink?
-high pressure and clear, dry conditions
Cyclonic storms
-swirl in a direction dictated by Coriolis efffect (clockwise in n, counterclockwise is s)
How do scientists respond to this? "Temperature changes are leveling off"
-temp tends to vary, but over decades, surface air temp and sea levels are rising
IPCC predictions
-warning of 1-6 Celsius by 2100 -"best estimate": 2-4 Celsius
Elliptical orbit, axis of rotation, axis wobbling cycles
E: 100,000 years A.R.: 40,000 years A.W.: 26,000 years
Hadley cells
Equatorial convection cells (one north and one south of equator)
Warmed air...
Expands, becomes less dense than the cooler air, and rises -the warm air cools and sinks-> convection cell
Positive feedback loop
Melting leads to further melting (dramatic consequences)
Precipitation happens when
Moisture cools and condenses
Svante Arrhenius
Predicted in 1895 that CO2 released by coal burning would cause global warming
How can we achieve stabilization?
Reduce annual carbon emissions by 7 billion tons (or 7 gigatons) per year within 50 years (or seven 1 gigaton slices)
3 important types of precipitations
Seasonal rain, frontal weather, and cyclonic storms
Tropopause
The boundary where mixing ends and air is no longer warmer than its surroundings (ceases to rise)
Pressure differences are an important cause of...
Wind -air moves from high pressure centers to low pressure areas (movement wind)
Ocean currents were once thought to be...
Unchanging, but oceanographers now think that they can change overtime -11,000 years ago, earth was warming at end of Pleistocene ice ages and Lake Agassiz contained lots of freshwater -drainage of this lake to the east was clocked by ice covering (ice dam gave way and water wen down and out into North Atlantic) -layered on top of ocean and prevented the sinking of cold, deep, dense seawater-> stopped oceanic conveyor baker and made planet go back into ice age
Weather patterns are influenced by...
Uneven solar heating on the earth's surface (spinning of earth)
Convection currents
Warmed air circulates in vertical and horizontal currents, which occur when warm low-density air rises above a cooler, denser layer -redistribute heat and moisture around the globe -troposphere
In the northern hemisphere, pressure centers move from
West to east
Surface ocean currents result from...
Wind pushing on the ocean surface and Coriolis effect -as surface water moves, deep water wells up to replace it (creating deeper ocean currents) -differences in water density (temp and saltiness) drive ocean circulation
