ES-200 Test 1 Material
3 isotopes of hydrogen
Duterium identified as "D" or "2D"
Evidence of Ice Ages
Evidence for advance of glaciers over North America and Eurasia discovered in the 1800s by Louis Agassiz - By analogy with features seen near modern glaciers in the Alps Boulders (erratics) moved far from their source bedrock Glacial striations gouged from rock Deep-sea core evidence for glacial cycles - glaciers melt sea level gets higher glaciers advance sea level lower - 18O in carbonate sediments (from hard shells of marine organisms)
Describe the charts on Slide 29 Aug 23 ppt
Figure SPM.1 | The complex relationship between the observations (panel a, yellow background) and the emissions (panel d, light blue background) is addressed in Section 1.2 and Topic 1. Observations and other indicators of a changing global climate system. Observations: (a) Annually and globally averaged combined land and ocean surface temperature anomalies relative to the average over the period 1986 to 2005. Colours indicate different data sets. (d) Global anthropogenic CO2 emissions from forestry and other land use as well as from burning of fossil fuel, cement production and flaring.
Projects for sea level rise
Following assessment statements apply to climate warming of the type projected for the 21st century by prototype IPCC mid-range warming scenarios, ...RCP4.5. Sea level rise will happen and should be causing higher storm surge levels for hurricanes that do occur, all else assumed equal.
How to make the historical record
Gather temperature observations from weather stations all over the world Calculate daily average for each day & station as (daily high + daily low)/2 Calculate the temperature anomaly for that station (difference from a baseline average) Average the temperature anomalies from all stations within a region of a given area Average the temperature anomalies from regions of equal area over the whole globe
Urbanization
Globally small footprint (1% land area), but rapidly increasing General term, "built up area" Density of structures and impervious surface greatly influence impacts on the environment Impacts climate Generation of pollution
How old is the earth believed to be?
4.5 billion years old
To keep CO2 concentrations in air at ___ ppm or less we need to change energy sources from coal to natural gas, and to decrease use of petroleum by using electric cars. Climate change impacts in NC will be felt gradually in the form of more intense hurricanes (categories 4 and 5) with up to ___ more rainfall. ___of the Outer Banks will increase. Inland flooding will also increase, and power outages will become more frequent and last longer.
550; 10%; erosion
What does IPCC stand for? And what do they do?
IPCC - Intergovernmental Panel on Climate Change Is the leading international body for the assessment of climate change. Established by the UN adn the WMO (World Meteorological Organization in 1988 to provide the policy makers with scientific data on climate change and its potential environmental and socio-economic impacts. does not conduct any reserach
What does imbalance imply?
Imbalance implies Earth's temperature hasn't "caught up" with increased levels of greenhouse gases - Year in & year out we throw more & more greenhouse "blankets" on the planet and increase IR absorbed and re-emitted to earth. - Even if we stop adding blankets, Earth's temperature keeps rising until Incoming radiation equal outgoing radiation.
what is nitrous oxide?
Laughing gas, now used as anesthetic, in past used to get high. Comments: N2O concentrations expected to rise as fertilizer usage increases. N2O will become third in greenhouse gas concentration, following methane, as halocarbons are phased out. Reducing the N2O concentration in atmosphere will be difficult. Major consumers of N fertilizer also grow rice which should release N2O. Major N consumer countries (China and India) have about 36% of World's population (7.6 billion).
methane is produced when ...
organic matter is eaten when no oxygen is present
What forms is carbon stored as in the ocean?
organic matter, shells, and dissolved C ions (C ions are used to build shells)
___ is the fuel that is used for the most energy. Most petroleum is used for transportation. About ___ of the energy in petroleum is wasted. Coal is still the fuel used to generate the most electricity. Natural gas is a close second. Note that ___ of the energy used to produce electricity is lost. The energy from nuclear power that is used to generate electricity is about the same as for natural gas
petroleum; 79%; 66%
Native Ecosystem Balances
Native ecosystem prioro to land use, was forested and grasland ecosystems. Balance between plant net primary production (NPP) (input) and microbial mineralization (output) Generally sinks of amospheric CO2 - inputs > outputs - globally ~2.5x more carbon stored in soils than vegetation
Does urban heat island explain global temperature rise?
No - Nearly identical global trends obtained with heat island correction; using only rural stations - Largest warming trends not in highly populated regions
Evidence of Early Eocene warm period - 55Ma
Temperature: Fossils 16-25 °F warmer globally High CO2: 2.5-5 times more CO2 than today Ellesmere Island like Southeast US cypress swamps
Why not just average all the station temperatures?
Temperatures in most developed countries would be way over-represented
Kyoto Protocol
The Kyoto Protocol to the United Nations Framework Convention on Climate Change (UNFCCC) was adopted in 1997 in Kyoto, Japan, at the Third Session of the Conference of the Parties (COP) to the UNFCCC. It contains legally binding commitments, in addition to those included in the UNFCCC. Countries included in Annex B of the Protocol (most Organisation for Economic Cooperation and Development countries and countries with economies in transition) agreed to reduce their anthropogenic greenhouse gas emissions (carbon dioxide, methane, nitrous oxide, hydrofluorocarbons, perfluorocarbons, and sulphur hexafluoride) by at least 5% below 1990 levels in the commitment period 2008-2012. The Kyoto Protocol entered into force on 16 February 2005.
insolation
The amount of solar radiation reaching the Earth by latitude and by season measured in W m-2. Usually insolation refers to the radiation arriving at the top of the atmosphere. Sometimes it is specified as referring to the radiation arriving at the Earth's surface. See also Total Solar Irradiance.
Greenhouse effect
The clear atmosphere is mostly transparent to visible light Some gases (greenhouse gases) absorb infrared radiation and re-emit it: Water vapor (H2O) Carbon dioxide (CO2) Methane (CH4) Nitrous oxide (N2O)
The eruption of mount tambora
The eruption caused global climate anomalies in the following years, while 1816 became known as the "year without a summer" due to the impact on North American and European weather. In the Northern Hemisphere, crops failed and livestock died, resulting in the worst famine of the century. The year 1816 is known as the Year Without a Summer (also the Poverty Year and Eighteen Hundred and Froze To Death)[1] because of severe climate abnormalities that caused average global temperatures to decrease by 0.4-0.7 °C (0.7-1.3 °F).[2] This resulted in major food shortages across the Northern Hemisphere.[3] Evidence suggests that the anomaly was predominantly a volcanic winter event caused by the massive 1815 eruption of Mount Tambora in the Dutch East Indies (the largest eruption in at least 1,300 years after the extreme weather events of 535-536), perhaps exacerbated by the 1814 eruption of Mayon in the Philippines. North America[edit] In the spring and summer of 1816, a persistent "dry fog" was observed in parts of the eastern United States. The fog reddened and dimmed the sunlight, such that sunspots were visible to the naked eye. Neither wind nor rainfall dispersed the "fog". It has been characterized as a "stratospheric sulfate aerosol veil".[7] The weather was not in itself a hardship for those accustomed to long winters. The real problem lay in the weather's effect on crops and thus on the supply of food and firewood. At higher elevations, where farming was problematic in good years, the cooler climate did not quite support agriculture. In May 1816,[1] frost killed off most crops in the higher elevations of Massachusetts, New Hampshire, and Vermont, as well as upstate New York. On June 6, snow fell in Albany, New York, and Dennysville, Maine.[8] In Cape May, New Jersey, frost was reported five nights in a row in late June, causing extensive crop damage.[9] Many commented on the phenomenon. Sarah Snell Bryant, of Cummington, Massachusetts, wrote in her diary, "Weather backward."[10] At the Church Family of Shakers near New Lebanon, New York, Nicholas Bennet wrote in May 1816, "all was froze" and the hills were "barren like winter". Temperatures went below freezing almost every day in May. The ground froze on June 9. On June 12, the Shakers had to replant crops destroyed by the cold. On July 7, it was so cold, everything had stopped growing. The Berkshire Hills had frost again on August 23, as did much of the upper northeast.[11] A Massachusetts historian summed up the disaster: Severe frosts occurred every month; June 7th and 8th snow fell, and it was so cold that crops were cut down, even freezing the roots .... In the early Autumn when corn was in the milk it was so thoroughly frozen that it never ripened and was scarcely worth harvesting. Breadstuffs were scarce and prices high and the poorer class of people were often in straits for want of food. It must be remembered that the granaries of the great west had not then been opened to us by railroad communication, and people were obliged to rely upon their own resources or upon others in their immediate locality.[12]
growing season
The number of days between the date of the last frost in the spring and the first frost in the fall. This is the part of the year when the weather conditions in a region, temperatuer and rainfall, permit plant growth. In NC, the growing season gets shorter when going from the coast to mountains. It begins from March 1 to May 15 and ends between September 1 and November 30
weather
The state of the atmosphere at a particular place and time as regards temperature, cloudiness, relative humidity, sunshine, wind, rain, etc.
What is the climate classification is used in the US and what are the different climate types in the US?
Trewartha climate type; rainforest, savanna, steppe, desert, mediterranean, humid subtropical, oceanic, continental, boreal, tundra, ice-cap
How does temperature change with height through the different layers of the atmosphere?
Troposphere cools with height but stratosphere warms with height, because reflecting of solar energy by troposphere clouds back into stratosphere
How nuclear power works?
Uranium isotope 235 (235U, 0.7% of U in nature) is fissionable - When struck by neutron splits into Krypton and Barium (radioactive isotopes) releasing energy and 2 to 3 neutrons - a chain reaction - Neutrons must be slowed to be absorbed (a moderator is needed) - Control rods limit pace of reaction (not a nuclear bomb) Water under pressure (e.g. Harris plant in Wake County) takes heat from fuel rods; generates steam. Electricity from steam turbines.
Findings from teh global temperature record
Warming: an increase (over land) of about 1.5 °C since 1900 1.5 °C = 1.8 x 1.5 =2.7 °F Noisy! Year to year fluctuations of about 0.1 °C Warming between 1900 and mid 20th century, roughly flat from 1940 to 1970, warming since 1970 with slight pause 2002-2012 Six warmest years in record since 2000
Climate sensitivity and uncertainty: Why is uncertainty so large (1.5 to 4.5 °C)?
Why is uncertainty so large (1.5 to 4.5 °C)? - Feedbacks Why is the range so large? - Forcing agents act on different time scales - Uncertain feedbacks: clouds - Uncertain past radiative forcing: aerosols
Climate variables can include:
air temperature, precipitation, air pressure, relative humidity, and wind speed and direction.
Matter
any substance that has mass and takes up space by having volume. generally includes atoms and anything made up of these
What regions of the world have warmed the most?
arctic, northern hemisphere land, and antarctic Peninsula
Isotopes
are elements with the same number of protons, but different numbers of neutrons Ex: 16O and 18O - numbers refer to atomic mass atoms used for dating top number in image is the atomic mass (# of nucleons) bottom number in image is the number of protons (# of protons = # of electrons
How does Earth lose energy?
as infrared radiation (IR or heat) Electromagnetic radiation with wavelengths too long to be visible to the human eye, but we feel it as heat.
chemical element is formed from:
atoms that have the same number of protons in their nucleus (that is, the same atomic number)
ions and two types
atoms with an electrical charge cation (+) - loses an electron anion (-) - gains an electron
Land use change over history
forested/grassland -> major land clearing for agriculture leads to Agrarian societies ("Agricultural revolution") -> Industrial Revolution leads to farm abandonment -> today the majority of global population lives in cities (major land use pressure)
Where does Earth's energy come from?
from the sun as sunlight (aka visible radiation)
What processes are causing CO2 to increase in the atmosphere?
fuels release CO2 when burned when cement is made population growth
Humans are the ____ cause of erosion
primary It is occurring at unnaturally high rates The US loses 5 tons of soil for ever ton of grain harvested Degradation of topsoil and decreased crop yields as population increases
What's the GWP of methane and carbon dioxide?
methane is 84 carbon dioxide is 1
what is the atomic mass?
number of protons plus the number of neutrons
land + ocean temperatures
ocean surface tmperatures form ships before 1980, from satellites after`
Every atom is made up of 3 kinds of smaller particles, called: (describe each one)
protons - positively charged neutrons - no charge electrons - negative charge
nucleas
protons and neutrons are heavier, and make up the nucleus. are surreounded by a cloud of electrons, which are very light in weight and are attracted to the positive charge of the nucleus.
Does deforestlantion/land use release of absorb CO2?
release
erosion
removal of material from one place to another (by wind or water; a problem when it happens faster than soil formation)
What causes sea level to change?
thermal expansion, which is: - water expands on warming: increase in heat energy leads to an increase in the distance between molecules - decrease in heat energy leads to decreasing distance between molecules - ice on land melts and water returns to ocean
sustainably
thriving now while ensuring future generations can thrive
Proxies include:
tree rings, pollen, oxygen isotopes, and stomata in fossil plants
What caused glaciers to form?
variations in earth's orbit Variations caused changes in the distribution of solar heating with latitude & season Milutin Milankovitch's (Serbian) theory: summer sunlight in high Northern latitudes matters Weak sunlight lets snow last over summer - builds up and changes into ice Winter sunlight doesn't matter - always cold enough for snow to stick These cycles partially explain why glaciers advance and melt periodically. Three orbital/rotational changes occur: eccentricity, precession, and tilt
What is Stefan-Boltzmann's law? Equation?
warmer bodies give off more energy (W/m^2) than cooler bodies Energy emitted (Flux)= σ x T4 Where σ is about 6 x 10-8 (Wm-2 K-4) and T is temperature in K
What is Wien's law? Equation?
warmer bodies give off radiation at shorter wavelengths than cooler bodies λ(μm) = 2900/T λ(μm) is wavelength of the light that is emitted the most (peak wavelength). T is temperature in Kelvin (K). oC = K - 273.
Positive feedback for climate:
water vapor feedback A warmer atmosphere "holds" more water vapor Water vapor is a GHG Rising T - stronger greenhouse - T rises more snow and ice albedo feedback Less snow & ice in a warmer climate Snow & ice reflect sunlight (high albedo) Rising T - less snow & ice - more sunlight absorbed - T rises more Potential "downstream" effects on ecosystems
Greenhouse gasses
water vapor, nitrous oxide, methane, carbon dioxide
Oxygen isotopes in shells come from _____ and _____ gas
water; CO2
what is the relationship between temperature and wavelength of light?
we can estimate temperature of bodies form the wavelength of light (or color) that they emit. increase in temperature is a decrease in wavelength as seen from Wien's law
methane sources
wetlands, fossil fuel burning, biomass burning, ruminants (cattle, sheep, antelope, deer, giraffes, etc. require nutrients from plan-based food by fermenting it anaerobically in their stomachs) , landfills, rice paddies, and termites
how is nitrous oxide produced?
when organic matter is eaten with NO3 when NO oxygen is around
Celsius
(C) water freezes at 0 C
Fahrenheit
(F) water freezes at 32 F
C =
(F-32)/1.8
Kelvin
(K) water freezes at 273
what are oxygen, hydrogen, and carbon isotopes used for?
- 16O, 18O past temperatures in ocean water - 1H, 2H past temperatures in ice - 12C, 14C dating, up to 50k years
Isotopes of Carbon
- Carbon-12: atomic weight = 12, isotope mass = 12 u, abundance: 98.89% - Carbon-13: atomic weight = 13, atomic mass = 13.00335 u, abundance = 1.109% - Carbon-14: atomic weight = 14, isotope mass = 14.003241 u, abundance = 1 part per trillion, half-life = 5730 +- 40 Years, used for carbon dating
What are the different states of matter and describe the process to get from one state to another.
- Gases, Liquids, and Solids - condensation: gas to liquid - evaporation: liquid to gas - sublimation: solid to gas - deposition: gas to solid - freezing: liquid to solid - melting: solid to liquid
Geological Time Scale
- Holocene includes last 12k years (after ice age ended and includes today. - Pleistocene is the ice age - only care about Holocene and Pleistocene (image on ppt includes up to Jurassic) - note the era, period, and epoch
Examples of IPCC Findings:
- Human influence on the climate system is clear, and recent anthropogenic emissions of greenhouse gases are the highest in history. Recent climate changes have had widespread impacts on human and natural systems. - Warming of the climate system is unequivocal, and since the 1950s, many of the observed changes are unprecedented over decades to millennia. The atmosphere and ocean have warmed, the amounts of snow and ice have diminished, and sea level has risen.
How does the 18O/16O ratio change in shells?
- when the organisms die, shells sink to form sediment - 18O/16O ratio of shell related to surface ocean surface temperature - warm period: 18/16 ratio is smaller in sample, low 18/16 ratio - cold period: 18/16 ratio is larger in sample, high 18/16 ratio
The Rain Shadow Effect
1. (bottom left, by the ocean) Moist, warm air blows onshore 2. (above clouds) As air rises over mountains, it cools, causing moisture to condense and fall as precipitation 3. (right side of mountain) dry air decends & warms, promoting evaporation - right side of mountain is called dry leeward slope - left side of mountain is the rainy windward slope - Ex: Asheville is in the rain shadow of air coming up from the Gulf and dumping its rain in Transylvania county. 100 inches of rain falls on the "windward" side of the Appalachians, but only 32 inches falls on the leeward slope and basin where Asheville is.
What happens when an anion meets a cation?
1. Anions have a negative charge (-): e.g. Chlorine: Cl- 2. Cations have a positive charge (+): e.g. Sodium: Na+ 3. When they meet, they combine to become a molecule. A simple compound is: NaCl (sodium chloride = salt).
isotopes of oxygen and what they're used for
16O: "Light Oxygen", 99.7% of all oxygen 18O: "Heavy Oxygen", .2% of all oxygen, amounts are so small that concentrations of it can't be used by themselves to estimate temperature; however, the ratio of the concentration of 18O to 16O can be used reliably to estimate temperature Two ratios must be evaluated: (18O/16O) of the sample- of water or a shell; (18O/16O) of a standard whose relationship to temperature is known
Increases in carbon dioxide, methane, nitrous oxide, and halocarbon gases have caused global temperatures to rise by about 1 oC since ____. Carbon dioxide accounts for about ___ of this rise. Methane and halocarbons each account for about ___ of the increase. Nitrous oxides account for only __ of the temperature rise.
1750; 63%; 15%; 7%
Record of temperature measurements only go back about ____ years. For information older than this we have to use ________ (________) for temperature measurements
200; "Proxies" (substitutes)
CO2 Absorbing and Re-emitting infrared radiation
Absorption of energy causes molecule to wiggle and stretch. Wiggling stops when energy is released Molecules of carbon dioxide (CO2) can absorb energy from infrared (IR) radiation. This animation shows a molecule of CO2 absorbing an incoming infrared photon (yellow arrows). The energy from the photon causes the CO2 molecule to vibrate. Shortly thereafter, the molecule gives up this extra energy by emitting another infrared photon. Once the extra energy has been removed by the emitted photon, the carbon dioxide stops vibrating. This ability to absorb and re-emit infrared energy is what makes CO2an effective heat-trapping greenhouse gas. Not all gas molecules are able to absorb IR radiation. For example, nitrogen (N2) and oxygen (O2), which make up more than 90% of Earth's atmosphere, do not absorb infrared photons. CO2 molecules can vibrate in ways that simpler nitrogen and oxygen molecules cannot, which allows CO2 molecules to capture the IR photons. Greenhouse gases and the greenhouse effect play an important role in Earth's climate. Without greenhouse gases, our planet would be a frozen ball of ice. In recent years, however, excess emissions of carbon dioxide and other greenhouse gases from human activities (mostly burning fossil fuels) have begun to warm Earth's climate at a problematic rate. Other significant greenhouse gases include water vapor (H2O), methane (CH4), nitrous oxide (N2O) and ozone (O3).
List symbols for Aluminum, Carbon, Calcium, Chlorine, Hydrogen, Potassium, Magnesium, Nitrogen, Sodium, Oxygen, Phosphorus, Sulfur, and Silicon:
Al, C, Ca, Cl, H, K, Mg, N, Na, O, P, S, Si
What is climate forcing?
An imposed change to Earth's radiative energy budget -Changes energy flows -"Force" climate system to change/respond -At TOA or at Earth's surface -Climate sensitivity (magnitude of response) drives uncertainty in predicted climate change effects -Measured in W/m2
What is Global Warming Potential?
An index (no units) based on .......measuring the radiative forcing over time following a pulse ... of ....greenhouse gas in the present day atmosphere, compared to that of carbon dioxide. The GWP represents the combined effect of the time these gases remain in the atmosphere and their relative effectiveness in causing radiative forcing [absorbing energy]..
For temperate rain forests of North America, area must have:
Annual precipitation over 140 cm (55 in), and mean annual temperature between 4 and 12 C (39 and 54 F)
Is Yucca Mountain safe?
Arid region, but there is ground water flow through the site. Seismic activity & volcanic risk Climate change (a million years is a long time) Politics -Obama administration withdrew support at request of Sen. Harry Reid (NV, then Senate majority leader) - Nevada does not want the site - Trump administration wants to restart project, $120M in proposed 2018 budget Law: Other states with wastes stored at nuclear plants suing to open Yucca Mountain
How do you develop some simple energy balance models?
Assume that Energy Inflows must equal Energy Outflows Adjustment to changes will be immediate Begin with one input, and add more to build increasingly complex models. Test model by how close it comes to matching observation that earth's average temperature is 15 C. 1) Develop equations that represent processes (e.g., flows) in the climate system. 2) Solve the equations on a computer by grid segments which represent a latitude-longitude-height for atmospheric and oceanic models. 3) Building and implementing conceptual models (parameterizations) for those processes that cannot be represented explicitly, because the processes are too complex (biochemical processes in vegetation) or because a process occurs at a given spot at a given time which can't be known in advance (volcanic eruption). 4) Compare predictions to observations 5) Adjust model components to bring predictions closer to observations.
Sun's energy reaching Earth
At the top of the atmosphere, where the Sun shines directly down (at equator), the Sun transfers energy at the rate of 1360 W/m2. Think of a burning 1360 watt bulb arranged at every square meter at the top of the atmosphere. That's enough energy per square meter to bring a liter of water from freezing to boiling in just 5 minutes. The 1360 W/m2 figure is correct only over the tropics. Averaged over the whole top of the atmosphere (a spinning sphere), the figure is closer to 340 W/m2. That's a 340 watt bulb continuously burning for every square meter. It is enough energy per square meter to bring a liter of water from freezing to boiling in 20 minutes.
Major Types of Climate Models: (Provide Model Type, Abbreviation, Usage, and Comments)
Atmosphere-Ocean General Circuilation Models - Abbrev: AOGCM - Usage: Study the dynamics of the atmosphere, ocean, land and sea ice on climate, and for making projections based on future greenhouse gas and aerosol forcing. - Comments: Older models, but still used for seasonal or decadal climate prediction where biogeochemical feedbacks not critical Earth System Models: - Abbrev: ESM - Usage: Various biogeochemical cycles including the carbon cycle, sulphur cycle, and ozone. Best models for simulating past and future responses of the climate system to external forcings - Comments: current stat of the art models that expand on teh AOGCMs Earth System Models of Intermediate COmplexity: - Abbrev: EMIC - Usage: Simplified versions of ESMs, used to understand climate feedbacks over time scales of thousands of years - Comments: may include components not in ESMs
Does CO2 drive climate or does climate drive CO2?
Both! Over millennia, lower global temperatures cause lower CO2 & visa versa How? We don't know! - During glacials, colder water holds more CO2 in ocean - But fast CO2 rise during warming periods is still unexplained
K =
C +273
Common Anions
Carbonate (CO32-) Chloride (Cl-) Nitrate (NO3-) Sulfate (SO42-) Phosphate (PO43-)
How much warming/cooling will occur due to climate forcings?
Change in temperature (∆T) = Radiative forcing X Climate sensitivity (0.8) Often given as ∆T for doubling CO2 Nominal values of 1.5 to 4.5 °C (2.7 to 8.1 °F)
What are agents of climate forcing?
Climate Forcing Agents: factors (natural and anthropogenic) that can change the Earth's climate (e.g. temperature and moisture) 1) incoming solar radiation: The sun has an 11-year sun spot cycle, which causes about 0.1% of the variation in the sun's output 2) Reflectivity (albedo): Change in cloud cover, glaciers, deserts, vegetation, aerosols (fog, dust, steam, smoke, air pollutants, soot) more reflection: promotes cooling less reflection: promotes warming magnitude of effect: doubling CO2: 4 W/m^2 (warming 3) Greenhouse gases (e.g., CO2, N2O, and CH4, H2O): IR absorption and re-radiation
Why is climate sensitivity so complicated? What are Feedback Loops?
Climate feedback is an internal climate process that amplifies or dampens the climate response to a specific forcing Positive Feedback Loop (Amplifies) Response to perturbation pushes system in same direction as the perturbation itself A produces more of B which in turn produces more of A Negative Feedback Loop (Dampens) Response to perturbation pushes system in opposite direction as the perturbation itself A produces more of B which in turn produces less of A Major driver of uncertainty
What are climate models? (Key points)
Climate models are attempts to represent Earth's climate system, so that we can better understand how it works, since can't conduct whole-earth experiments. Climate models are grounded in physics, chemistry, and biology Climate models are tested against observations in the real world. Even fairly simple climate models, like energy balance models, can help us understand and represent important processes in the Earth's climate system. Comparing model output to observations helps check how well the models represent Earth's climate system. Climate models have done pretty well modeling global temperatures. In some cases, models have underestimated actual rates of change in the climate system, notably with sea ice and sea level rise. Model projections of future temperatures show high latitudes and land continuing to warm faster than low latitudes and ocean. To model into the future, climate models need to have information about possible emission scenarios. The RCPs start by defining endpoints for radiative forcing at a future time, then define representative emissions pathways to get to those endpoints. These scenario examples give us information about what the future might hold depending on our choices.
Earth's deep-time climate history: cold, warm, varying (what time period?)
Cold: snowball Earth (610 Ma*) Warm: Eocene thermal maximum (55 Ma) Varying: Pleistocene glacials (starting 2.6 Ma) (Ma = millions of years ago)
Global Warming Potentials
Compares ability of different gases to absorb radiation in the present atmosphere, compared to that of CO2. Gases are added in the same amounts as CO2 for testing. Because current CO2 concentrations are high, adding additional CO2 has relatively little impact on its radiative forcing. Gases with high GWP also are present in relatively low concentrations limiting their effectiveness. GWP may be the reason for statements like: methane "is 84x more potent a greenhouse gas" than CO2. It may be, but since there isn't much methane in the atmosphere its impact on temperature is less than what GWP might imply.
Two types of solar:
Concentrated solar power (CSP) - Uses mirrors to concentrate heat to warm fluid to drive a turbine Solar voltaics (PV) - Solar cells
What are convection cells?
Convection cells circulate air, moisture, and heat around the globe. Jet streams develop where cells meet, and surface winds result from convection. Convection cells expand and shift seasonally.
CO2 produced in soil when 3 things are present:
Dead organic matter oxygen in air bacteria CO2 produced when organic matter is eaten when oxygen is present
CO2 from land use changes
Deforestation and "prairie busting" for agriculture Leading human source of CO2 emissions before 1950 Declining in relative & absolute magnitude Competition between tropical deforestation & afforestation elsewhere Ex: Tropical Deforestation in Indonesia for oil palm plantations
What's an anomaly?
Difference between the temperature at a station on a given date and the 1951-1980 average of temperatures at the same station on the same day of the year Anomaly: measurement on given date minus an average Why take anomalies? - Temperatures at the stations in a region may not be representative of the temperatures in a whole region, but the changes over time at that station are likely to track the changes throughout the region - Taking anomalies lets us compare temperature changes in different seasons
Energy Balance Model 4
Greenhouse gases absorb all radiation from surface, and emit one half upward and one half downward. For earth to be in energy balance, the amount of emission to space must equal amount of solar radiation absorbed, or 238 Wm-2. Because the upward and downward emissions are the same, then the earth's surface must emit an amount equal to the net solar radiation absorbed plus the radiation emitted downward by GHGs. This is 238 + 238 W/m2 or 476 W/m2.
How will sea level rise and hurricanes affect outer banks?
Higher sea levels will make damage from hurricane storm surges worse. Erosion rates of Outer Banks may increase.
Alternative Energies Pros & Cons: Hydroelectric, Nuclear, Wind, Solar, Biomass
Hydroelectric - Pro: clean, mature technology - Con: limited availability for new sites in U.S. Nuclear - Pro: operated (mostly) safely; improved technologies possible - Con: risks of accidents; low public acceptance; waste disposal issue Wind - Pro: clean: has emerged as reliable contributor at competitive cost - Con: intermittency; aesthetic objections; impacts on birds & bats Solar - Pro: clean; appealing for low-latitudes - Con: intermittency; cost Biomass - Pro: can be carbon neutral - Con: landscape impact; competition with food-crop cultivation; pollution from combustion
Common cations
Hydrogen (H+) Ammonium (NH4+) Potassium (K+) Magnesium (Mg2+) Calcium (Ca2+)
Urban Areas and Climate
Impervious surfaces cap soils Removal of topsoil prior to construction Mineralization without plant inputs Many soil impacts, unknown! Generally not favorable for plant growth No rooting, soil compaction, pollution (atmospheric, soil, water) NOx + VOC + Sunlight = Ozone Capping = net loss of area for photosynthesis and CO2 removal
climate sensitivity
In IPCC reports, equilibrium climate sensitivity (units: °C) refers to the equilibrium (steady state) change in the annual global mean surface temperature following a doubling of the atmospheric equivalent carbon dioxide concentration. Owing to computational constraints, the equilibrium climate sensitivity in a climate model is sometimes estimated by running an atmospheric general circulation model coupled to a mixed-layer ocean model, because equilibrium climate sensitivity is largely determined by atmospheric processes. Efficient models can be run to equilibrium with a dynamic ocean. The climate sensitivity parameter (units: °C (W m-2) -1) refers to the equilibrium change in the annual global mean surface temperature following a unit change in radiative forcing. The effective climate sensitivity (units: °C) is an estimate of the global mean surface temperature response to doubled carbon dioxide concentration that is evaluated from model output or observations for evolving non-equilibrium conditions. It is a measure of the strengths of the climate feedbacks at a particular time and may vary with forcing history and climate state, and therefore may differ from equilibrium climate sensitivity. The transient climate response (units: °C) is the change in the global mean surface temperature, averaged over a 20-year period, centred at the time of atmospheric carbon dioxide doubling, in a climate model simulation in which CO2 increases at 1% yr-1. It is a measure of the strength and rapidity of the surface temperature response to greenhouse gas forcing
What is a proxy?
Is something measured that can be related to the temperature under which it formed.
Chemistry:
Is the branch of science concerned with the atoms of which matter is composed, their properties and reactions, and hte use of such reactions to form new substances.
4 key facts about electromagnetic radiation (light, heat):
It travels through the vacuum of space Everything gives off electromagnetic radiation all the time if temp. > 0 K Warmer bodies give off radiation at shorter wavelengths than cooler bodies Warmer bodies emit more energy (more Wm -2)than cooler bodies
Earth Temperature at the Mesozoic - Cenozoic boundary (~65 million years ago). This is also called the _-_ boundary (now called "________-_______"), at which the dinosaurs became extinct.
K-T; Cretaceous-Paleogene
Describe/Evaluate Climate Sensitivity
Magnitude of climate response to a forcing Commonly expressed in terms of the global mean temperature change that would be expected after a time sufficiently long for both the atmosphere and ocean to come to equilibrium with the change in climate forcing (typically the doubling of atm CO2). Timescales are important: Decades to centuries - Oceans store large amounts of heat that may take some time to come into equilibrium before atmosphere warms If there were no climate feedbacks, the response of Earth's mean temperature to a forcing of 4 W/m2 (the forcing for a doubled atmospheric CO2) would be an increase of about 1.2°C (about 2.2°F). However, the total climate change is affected not only by the immediate direct forcing, but also by climate "feedbacks" that come into play in response to the forcing.
Terrestrial to atmosphere interactions: law of conservation of matter: major players
Major players: Plants (photosynthesis) Microbes (mineralization, CH4, denitrification) Humans (land use change interrupts ecosystem balance) Terrestrial zone of interaction = critical zone Soil!
Climate Change Feedbacks
Microbial process depend on temperature More efficient at higher temps. Increasing temperatures, greater fluxes of CO2, N2O, CH4
At the ________-________ boundary, ~5.3 million years ago
Miocene - Pliocene
How do you measure sensitivity?
Models can't give us a precise number But, Change in temperature (∆T) = Radiative forcing X Climate sensitivity So if we know ∆T & the Radiative forcing, we can better predict climate change...
Climate Change Impacts on Agriculture
More extreme heat More drought - Heat & drought are correlated - Crop plants are vulnerable to extreme heat alone - Drought & heat demand more irrigation Aquifer depletion More irregular rain - longer dry periods with more intense rainfall - Increased soil loss to erosion
Is Earth today in energy balance?
No, more incoming solar radiation received Excess is only about 1 Wm^-2
Effect on Hurricane numbers and rainfall from climate change:
Numbers of yearly hurricanes may remain the same or decrease slightly. Hurricane rainfall rates will likely increase in the future due to warming. Modeling studies on average project an increase on the order of 10-15% for rainfall rates averaged within about 100 km of the storm for a 2 oC global warming scenario. Severity of floods should increase as a result Hurricane intensities globally will likely increase on average (by 1 to 10% according to model projections for a 2 oC global warming). Hurricanes of Category 4 and 5 levels will likely increase.
Climate MOdel Intercomparison Project (CMIP5)
Over 100 climate models have been developed from research groups around the world No one model is considered better than any other in predicting future climate changes. CMIP5 will get modeling groups (50+) to run the same experiments with their models, and compare results. Results can be averaged over time, and compared to observations. Grouped results produce a "multimodel ensemble" Examples of CMIP5 Experiments (out of 50+): -Past 1.5 Centuries (1850-2005) - Model used: AOGCM and ESM or MIC; major purpose: model evaluation
Additional considerations to forest/grassland conversion to agriculture
Primarily comes from agricultural/urban areas ~300x more global warming potential than CO2 Anthropogenic N fertilization Excess N (water pollution) Denitrification (anaerobic) 2 NO3− + 10 e− + 12 H+ → N2 + 6 H2O Incomplete product = N20
Additional considerations to forest/grassland conversion to agriculture: Methane
Production in anoxic (anaerobic) conditions CO2 + 4 H2 → CH4 + 2 H2O 25x more warming potential than CO2 Agriculture: Enteric fermentation (primarily cattle, rumen) Manure management Capped landfills with organic waste Other anthropogenic sources?
What is Radiative Forcing?
Radiative forcing is a measure of the influence [strength] a factor has in altering the balance of incoming and outgoing energy in the Earth-atmosphere system, and is an index of the importance of the factor as a potential climate forcing mechanism. Radiative forcing values show changes relative to pre-industrial conditions defined at 1750 and are expressed in Watts per square meter (W/m2).
radiative forcing
Radiative forcing is: the change in the net, downward minus upward, radiative flux (W m-2) at the ....top of atmosphere caused by a change ...., for example, ...in the concentration of carbon dioxide .... For the purposes the IPCC reports, radiative forcing is further defined as the change relative to the year 1750 and, unless otherwise noted, refers to a global and annual average value
Climate Type Descriptions (symbol and description) of a Rainforest, Desert, Steppe (prairie), and Boreal:
Rainforest - Ar - Tropical climate, winterless and frost-free, no more than 2 dry months (<60mm), so high precipitation; Desert - BW - Low recipitation, determined by formula using average annual temperature, and precipitation; Steppe - BS - More precipitation than desert, but less than twice as much, defined by formula; Boreal - E - Cold, 1-3 months have average temp. of 10 C (50 F) or above
Where does global temperature uncertainty come from?
Range of projected year 2100 temperature: 5 °C (9 °F) Uncertainty comes from projections of emissions (RCP*s) Uncertainty comes from how much radiative forcing results from emissions Uncertainty comes from range of model sensitivities to radiative forcing RCP (Representative Concentration Pathway): different scenarios for industrial/energy development & climate change mitigation policies Uncertainty (big) comes from mitigation pathway - what will we choose to do? Uncertainty within a pathway comes from chemistry & interactions with climate projections of global temperature need projected forcing
Representative Concentration Pathways (RCPs)
Scenarios that include time series of emissions and concentrations of the full suite of greenhouse gases and aerosols and chemically active gases, as well as land use/land cover (Moss et al., 2008). The word representative signifies that each RCP provides only one of many possible scenarios that would lead to the specific radiative forcing characteristics. The term pathway emphasizes that not only the long-term concentration levels are of interest, but also the trajectory taken over time to reach that outcome. (Moss et al., 2010). RCPs usually refer to the portion of the concentration pathway extending up to 2100, for which Integrated Assessment Models produced corresponding emission scenarios. Extended Concentration Pathways (ECPs) describe extensions of the RCPs from 2100 to 2500 that were calculated using simple rules generated by stakeholder consultations, and do not represent fully consistent scenarios. Four RCPs produced from Integrated Assessment Models were selected from the published literature and are used in the present IPCC Assessment as a basis for the climate predictions and projections presented in Chapters 11 to 14: RCP2.6 One pathway where radiative forcing peaks at approximately 3 W m-2 before 2100 and then declines (the corresponding ECP assuming constant emissions after 2100) RCP4.5 and RCP6.0 Two intermediate stabilization pathways in which radiative forcing is stabilized at approximately 4.5 W m-2 and 6.0 W m-2 after 2100 (the corresponding ECPs assuming constant concentrations after 2150 RCP8.5 One high pathway for which radiative forcing reaches greater than 8.5 W m-2 by 2100 and continues to rise for some amount of time (the corresponding ECP assuming constant emissions after 2100 and constant concentrations after 2250)
Sea Ice Change from sept. 1980 to 2012
Sea ice change from September 1980 to September 2012. Melting ice produces positive feedbacks with greater heat absorption and later freezing in the fall.
Energy Balance Model 1:
Simplest Case: No sun shining on earth Earth's temperature is 32 K (-241 C): Dark and cold The earth is warmed by heat produced by radioactive decay occurring in Earth's interior and residual heat leftover from when Earth formed. At 32 K, Earth emits 0.06 W/m2 to be in energy equilibrium *more factors are accounted for as model 2, 3, 4, and etc are produced (Ex: model 2: sun shines, model 3: sun shines and reflection added, model 4: sun shines and reflection added and greenhouse gasses added, and etc)
What is the waste problem from nuclear power?
Spent fuel rods (depleted in 235U) stay dangerously radioactive for thousands of years - Now: on-site at power plants: space is limited; security/safety concerns Plan (Congress: 1987) is to move spent fuel to nuclear waste repository - Yucca Mountain, Nevada, selected - Supposed to open in 1998 - still not open - Supposed to protect public from radioactivity for a million years - Waste in casks in tunnels well above water table
Energy Balance Model Equation
Stefan-Boltzman Equation Energy Flux (W/m2) = σ x T4 σ = constant = 5.67 x 10-8 W m-2 K-4 T = temperature in K oC = K - 273 amount of radiation emitted by a body depends on its tempeterature
Latent heat flux
The turbulent flux of heat from the Earth's surface to the atmosphere that is associated with evaporation or condensation of water vapour at the surface; a component of the surface energy budget.
What can we do to prevent erosion rates?
beach nourishment: Move sand from off-shore (underwater) source onto beach Must do every 7-10 years Expensive, but only way to preserve the beach. 30 projects completed along coast since 1939 Total Length of Beach Restored: 500,116 ft. (95 miles) Total cost: $790,185,233 Average cost/ft: $1,580/ft Range in Cost: $356/ft to $5,261/ft Average number of events/beach: 10 Carolina Beach renourished 38 times since 1955 , structures, relocation
How do we know rising CO2 comes from fossil fuels?
because of the Suess effect! which says: 14C is radioactive carbon - Forms in atmosphere - Decays: 5,730 year ½-life Fossil fuel C buried for millions of years, has no 14C Fossil fuel C dilutes 14C in the atmosphere, expect 14C concentration to go down
Why doe sthe sun emit visible light, but the earth does not?
because the sun is hotter than the earth
stomata in fossil plants
carbon dioxide enters the stomata, while water and oxygen (O2) exit through the stomata. more stomata = cooler temperature can look back 400 million years
what are halocarbons
chemcials that thin the ozone layer Halocarbons --Fire retardants (fire extinguishers) --Soil fumigant/pesticide --Solvents --Foam blown-in insulation Chlorofluorocarbons (CFCs) --Coolant/refrigerant/air conditioner --Aerosol or propellant --Foam-blowing plastics (Styrofoam) --Solvent/cleaners Halocarbons are: Man-made gases Composed of atoms of carbon, chlorine, fluorine, bromine, and hydrogen. Have the third highest radiative forcing after carbon dioxide and methane. Includes Freons as well as gases labeled as: CFC-12, HCFC-22, SF6, HFC-125 Lifespan in atmosphere: 1 to 50,000 yr Halocarbons decompose in stratosphere to release Chlorine (Cl). This destroys the ozone which absorbs ultraviolet radiation. Montreal Protocol (1987) regulated emission of halocarbons, and their concentrations are decreasing. Hydrofluorocarbons (HFCs) replaced halocarbons and have less impact on ozone. HFCs are also strong greenhouse gases and they are being phased out too.
less clear feedback for climate:
clouds and water Water also influences cloud formation More cloud cover or less cloud cover in a warmer climate? (uncertain) Do clouds warm or cool? (Both) Climate models don't do clouds well
what are levees?
constructed mounds along channel that keep flood waters off flood plain
Agriculture:
conversion from native forest/grasslands to cropland/rangeland: Substantial initial losses of stored carbon Deforestation outpacing afforestation (net loss) Currently second largest CO2 source to atmosphere Coupled issues with erosion, decreased NPP, ever increasing global population Historically large losses of stored carbon Plant carbon lost via combustion and/or mineralization Estimated 30->60% stored soil carbon loss Needed to feed ever growing population 7.6 billion today, 9.5 billion by 2050 Today, ~34-37% of land cover = agriculture
Oxygen Isotope Ratios Reported (called Delta)
delta18O = ((18O/16O)sample - (18O/16O)standard)/(18O/16O)standard x 1000 standard = Standard Mean Ocean Water (SMOW) Standard uses SMOW = 2 per thousand or mille VSMOW2 may be the newer one As 18O increases in sample, the delta becomes more positive
tree rings
each year has 2 rings thick light brown ring is spring/early summer growth dark thin ring is late summer/fall growth dry season has narrower rings rainy season has thicker rings dark spots are scars from forest fires middle ring is the first year of growth
Figure 2.10: The frost-free season length, defined as the period between the last occurrence of 32°F in the spring and the first occurrence of 32°F in the fall, has increased in each U.S. region during 1991-2012 relative to 1901-1960. Increases in frost-free season length correspond to similar increases in _________ __________ length. (Figure source: NOAA NCDC / CICS-NC). (Figure on slide 21 ppt Aug-31)
growing season
What caused the glaciers to grow periodically?
he extent of the Cordilleran and Laurentide Ice Sheets near the peak of the Wisconsin Glaciation, around 15 ka. [redrawn by SE based on a map at: https://www.ncdc.noaa.gov/paleo/glaciation.html]
To keep CO2 concentrations low, need to use low-carbon-intensity fuel sources like...
hydro, ocean, wind, nuclear, biomass, solar CSP, Geotherm, Solar PV
glacier
is a long-lasting body of ice (decades or more) that is large enough (at least tens of metres thick and at least hundreds of metres in extent) to move under its own weight. Glaciers form by accumulation of snow. Glaciers store the most of the fresh water on Earth (~69% of all fresh water), and they are highly sensitive to changes in climate. About 10% of Earth's land surface is currently covered with glacial ice, and although the vast majority of that is in Antarctica and Greenland, there are many glaciers in Canada, especially in the mountainous parts of B.C., Alberta, and Yukon and in the far north (Figure 16.1). At various times during the past million years, glacial ice has been much more extensive, covering at least 30% of the land surface at times. Glaciers represent the largest repository of fresh water on Earth (~69% of all fresh water), and they are highly sensitive to changes in climate. In the current warming climate, glaciers are melting rapidly worldwide, and although some of the larger glacial masses will last for centuries more, many smaller glaciers, including many in western Canada, will be gone within decades, and in some cases, within years. That is more than just a troubling thought for western Canadians because we rely on glacial ice for our water supplies — if not for water to drink, then for water to grow food. Irrigation systems in B.C. and across Alberta and Saskatchewan are replenished by meltwater originating from glaciers in the Coast Range and the Rocky Mountains.
Urban Heat Island
is an urban/metropolitan area that is significantly warmer than its surrounding rural areas due to human activity Reduced albedo - Dark surfaces - Trapping by urban "canyons" Impermeable surfaces - drastically reduced evapotranspiration Increased roughness - reduced wind Heat released from buildings - Winter: leaking heat - Summer: pumped out by AC Cities up to 10 °F warmer
climate
is defined as teh "average weather," or more rigorously, as the mean and variability of temperature adn precipitation overa period of time. The usual period is 30 years, as defined by the World Meteriological Organization (WMO)
atom
is teh smallest unit of ordinary matter that has the properties of a chemical element. every solid, liquid, and gas is composed of neutral or ionized atoms
Radiative Forcing (RF)
is the difference in incoming and outgoing radiation at the top of the Troposphere If an RF is positive, that means that more heat producing radiation is coming in to Earth than is being lost to space. Positive RF's mean the Earth is going to heat up, negative RF's mean it will cool down. An RCP of 8.5 (RF of 8.5 on 2100) will have more greenhouse gases in the atmosphere than an RCP 2.6, and temperatures will be much higher.
soil degradation
loss of soil quality and productivity
Effects of tropical Deforestation
lower albedo, less reflected radiation, more heat, evaporation, mineralization, anaerobic to aerobic conditions
Watt
measure energy over time. A 60 watt light bulb uses 60 joules of energy per second 1 joule per second
1 Watt/m2 of visible light transfers the _____ amount of energy as 1 Watt/m2 of infrared light. If a body's temperature is rising, then the amount of energy coming into it is _____ the amount of energy leaving it. If a body's temperature is falling, then the amount of energy coming into it is _____ the amount of energy leaving it. If a body's temperature is stable, then the amount of energy coming into it is ______ to the amount of energy leaving it.
same; greater than; less than; equal
How can we live sustainably with a changing climate? (a climate that changes on its own)
slow down climate change ("mitigation") and adapt to the changing climate ("adaptation")
Ratios of 18O/16O in ocean water are ___ during warm periods. (____ 16O). Ratios of 18O/16O are _______ during cold periods (Ice Ages) (____ 16O)
small; more Ocean water contains some water molecules with 18O and others with 16O. Water that is evaporated contains more vapor with 16O than 18O, because 18O is heavier and needs more energy to vaporize and lift it out of the ocean. When it rains, the water flows back to the ocean returning the molecules containing 16O, so that the quantities of the two isotopes remains about the same over time. larger;less During cold periods much evaporated water stored in ice as in glaciers. The ice contains primarily water with 16O. This leaves the oceans enriched with water containing 18O. So the ratios of 18O to 16O are high in the ocean water.
Oxygen Isotope-Temperature Curve: The ______ (more _______) the Delta18O the _____ the temperature
smaller; negative; warmer pertains to carbonate shells growing in seawater
teh mass of an atom is determined by:
teh number of protons and neutrons
Normal Rainfall
the average rainfall determined for an area over a 30 year period
For an average spot on Earth's surface, at an average day and time... (describe the flux)
the downward flux of infrared radiation from the atmosphere is greater (by almost 2 x) than the incoming sunlight
Calorie
the heat or energy needed to raise the temperature of 1 gram of water by 1 degree celsius (4.2 joules)
Joule
the heat required to raise hte temperature of 1g of water by .24 C
What determines the atomic number?
the number of protons
