221 midterm Flashcards
(77 cards)
1
Q
weather vs climate
A
- weather is a specific location for a specific or short period
- climate is the averaged atmospheric conditions over a long period of time (usually 30 years)
2
Q
anthropogenic vs natural climate change
A
- Climate change may be due to natural internal processes, external forcings, or to persistent anthropogenic changes (human caused)
- ex of anthropogenic causes: deforestation and burning fossil fuel
- ex of natural causes: The sun, volcanic forcing, and climate variability (ENSO)
3
Q
how will climate change in the future?
A
- varying degrees of temperature and precipitation changes across different regions
- more extreme weather events
- sea level will rise
4
Q
some things that determine the climate
A
- Solar radiation
- Atmospheric composition (gases and aerosols)
- Surface characteristics (albedo, roughness, etc)
- Humans can change the climate by affecting 2 or 3
5
Q
examples of long term climate change
A
- ice age
- medieval warming period (800-1200 AD)
6
Q
ice age
A
- 65 million years ago
- The sudden cooling of the earth’s climate is thought to have caused the extinction of 75% of the planet’s plant and animal life
- Not fully understood. Likely causes include: Changes in orbital forcing – the Milankovitch cycles; Atmospheric composition, such CO2 and CH4 concentrations
7
Q
Medieval warming period
A
- The arctic ice expanded, glaciers advanced
- These changes may have been due to variations in: shape of Earth’s orbit, tilt of the axis, or gyration of the rotation axis
8
Q
different types of climate variability
A
- Climate variability- deals with smaller scale
- Climate change- downward trend away from normal
- Periodic change- ex: seasons; see patterns
- Abrupt change- sudden change; ex: volcanic eruption
9
Q
the 5 climate characteristics
A
- Cryosphere (ice)
- Hydrosphere (water)
- Lithosphere (layers of Earth)
- Atmosphere (air)
- Biosphere (life)
10
Q
how climate change can change these characteristics
A
- cryosphere- melting snow and ice
- hydrosphere- Rising sea levels due to melting glaciers and ice sheets
- lithosphere- increased weathering and erosion caused by changes in precipitation patterns
- atmosphere- increases GHG emissions
- biosphere- changes distribution and abundance of species (deforestation)
11
Q
Intergovernmental Panel on Climate Change (IPCC)
A
- United Nations-led group of scientists that assesses climate change and provides policy recommendations
- 3000 scientists from more than 150 nations
12
Q
Different assessment reports for IPCC and what happened at them
A
- First Assessment Report (FAR), 1990- predicted pace of global warming
- Second Assessment Report (SAR), 1995- Obvious human influence on climate change
- Third Assessment Report (TAR), 2001- human activities are responsible for global warming
- Fourth Assessment Report (AR4), 2007-Global temperatures, sea levels, and snow and ice melting are all increasing
- Fifth Assessment Report (AR5)- climate change has widespread impacts
13
Q
climate change vs global warming
A
- Climate changs is the statistically significant variation in either the mean state of the climate or in its variability, persisting for an extended period
- Climate change may be due to natural internal processes, external forcings, or to persistent anthropogenic changes (human caused)
- Global warming talks about the current increase in the average temperature overtime in the Earth’s atmosphere and oceans
- Global warming Implies that humans are the cause of it (called “anthropogenic climate change”)
- global warming is more controversial
14
Q
info about climate past
A
- Tree rings, rock formations, earth material
chemical composition, lake-floor sediment, etc. - These are climate proxies, and each have advantages and disadvantages
15
Q
moisture
A
- Precipitation- water, in liquid or solid form, that falls from the atmosphere and reaches the earth
- Humidity- the amount of water vapor in an air mass at a given time
16
Q
relative humidity
A
- a comparison of how much water vapor is present in the air to how much water vapor would be in the air if the air were saturated
17
Q
pressure and air pressure
A
- The force exerted by the weight of the atmosphere on the Earth’s surface
- The “air pressure” at a given location is highest at sea level and decreases with altitude due to the decreasing amount of air particles at higher altitudes
- Colder air is denser than warm air, and warm air is lighter than cold air
18
Q
high and low pressure systems
A
- Low pressure system cause storms as the air rises and creates clouds
- High pressure systems cause heat waves and droughts, as air sinks and causes clear skies
19
Q
troposphere
A
- Lowest part of the atmosphere
- Where we live
- Tropopause is the boundary between the troposphere and stratosphere
20
Q
three reasons why temperatures vary from place to place
A
- The sun-we have uneven heating of the surface of the Earth from the sun
- Insolation- the amount of incoming solar radiation
- Depends on the intensity and duration of radiation from the sun, which is determined by angle of sun’s rays and number of daylight hours - Temperature are heavily moderated by large bodies of water
- Some earth surface materials (like water) store solar energy more efficiently than others
21
Q
three ways that precipitation can occur
A
- Convectional- results from rising, moist air that cools
- Orographic- warm, moist air is forced to rise over hills or mountains and condensed and cools
- Rain shadow effect- dry on one side of mountain, rainy on the other - Cyclonic- precipitation that occurs as a result of cool and warm air masses meeting
- Air mass- big chunk of air that has some type of temperature property
- Front- refers to the zone that separates the two air masses
22
Q
jet streams
A
- belts of the strongest flow of upper air winds
- Flow from west to east in an undulating path
- They guide the movement of weather systems
23
Q
hadley cell
A
- low-latitude overturning circulations that have air rising at the equator and air sinking at roughly 30° latitude
24
Q
biome
A
- a group of land ecosystems with similar climates and organisms
- There are 6 major land biomes and 2 water biomes
25
The 6 land biomes and 2 water biomes
- water: freshwater and marine ecosystems
- land: rainforests, deserts, grasslands, deciduous forests, boreal forests, tundra
26
Climate regions and the categories
- Main climate type: ex: polar, tropical
- Something more specific dealing with weather:ex: desert, fully humid
- Something dealing with season: ex: warm summer, cool summer
27
In the summer, which hemisphere recieves more direct sunlight?
- The southern hemisphere
28
Keeling curve
- A graph that shows us the concentration of carbon dioxide in parts per million
- Observed in Mauna Loa, Hawaii, where the Earth's air is sampled
- concentration rises throughout the year, but then decreased in September
- This is because in the fall, plants decay and decompose, releasing CO2
- the entire curve has been increasing exponentially
29
radiation
- Can be absorbed, emitted by all matter, depending on temperature and “emissivity” of the material
- All objects warmer than 0 Kelvin emit radiation, depending on their
temperature
30
Albedo
- how reflective a surface is
- Earth's albedo is reflected by clouds, aerosols, and the surface
- Ex: snow and ice have a high albedo and water has a lower one, absorbs more of the sun’s energy
- High allbedo surfaces bounce sunlight back
31
Ice-albedo positive feedback
- cooling (e.g., due to orbital forcing) produces more ice and snow cover, which further cools the Earth; while warming reduces the ice and snow cover, which further enhances the warming
- CO2 and CH4 levels fell at the start of ice ages and rose during the retreat of ice sheets
- accelerated the formation and melting of the snowball
32
Outgoing longwave radiation
- The amount of heat that Earth emits into space balance of ingoing and outgoing energy
33
latent heat
- Deals with extra heat during the change of water phases
34
heat transfer
- heat transfers in air and ocean, which balances the surplus of energy in the tropics and the deficit of energy at the poles
35
The Diurnal Variation
- The sun setting and rising causes variations in the Earth’s properties throughout the day (temperature, Sunlight, magnetic field)
- This has a lot of radiative driving
- The solar part goes from 0 to a large number, and the longwave part doesn’t change much
36
Two potent compounds in the atmosphere
- carbon dioxide (9-26%) and water vapor (36-72%)
37
short-term organic carbon cycle
- involves processes that operate on a daily to seasonal time scale, such as respiration and photosynthesis by plants and algae
38
Phytoplankton
- natural way we get CO2 in atmosphere
- Take in carbon and when they die, they sink to the bottom of the ocean
39
biological pump
- the process by which CO2 is removed and transferred from the surface of the ocean to deeper parts
40
upwelling
- when deep and cold water brings nutrients back into the surface
41
The global ocean conveyor belt
- shows how heat is transferred across the ocean throughout the globe
- Transfers heat and oxygen rich water
- Colder water holds more gas that warm water
- Higher atmospheric CO2 levels -> higher surface temperature->higher weathering rates->higher consumption of CO2
42
ocean acidification
- A decrease in ocean pH over decades or more that is caused primarily by uptake of CO2 from the atmosphere
- Because human activities are releasing CO2 into the atmosphere very quickly, the ocean is taking up CO2 faster today than it has in the past
- This is causing global ocean chemistry to change more quickly than ocean systems can handle
43
Anthropogenic fluxes
- only about half of the human produced CO2 inputs stays in the atmosphere
- The rest is taken up by the oceans and by the terrestrial biosphere
- Oil, gas, and coal have used the most CO2 emissions
44
the methane cycle
- goes in and out of landfills
- Anthropogenic concern
- Burning fossil fuels can release methane
- Burning biomass (forests, organic materials) add methane to the atmosphere
- Permafrosts melting releases methane into the atmosphere
45
the hydrological cycle
- The transportation of water
- Helps re-distribute water and energy on Earth
- Most water on earth is in the ocean
- 2.5% freshwater
- Of all freshwater, most is in glaciers and ice caps, and then groundwater
46
main fluxes of the hydrological cycle
- Surface to the atmosphere: evaporation land and ocean
- The atmosphere to the surface: precipitation land and ocean
- Atmospheric transport: Ocean to land
- Land to ocean runoff
47
infiltration
- flow of water from surface into the grounds (soils)
48
runoff and the two types
- Runoff- lateral movement of water on land
- Surface runoff- the water flow on Earth’s surface
- Only when the soil is saturated or can not absorb water from rain or snow/ice melt fast enough
- Subsurface runoff (or return flow)- the lateral water flow below the Earth’s surface, usually following the terrain under gravity
49
climate variability
- variation of any climate variable over many years (precipitation, temp, trade winds, etc)
- The variations can be from season to season, year to year, decade to decade
- Natural fluctuation from year to year or decade to decade are called inter-annual modes
- examples of inter-annual modes: En Nino southern oscillation (ENSO) and North Atlantic oscillation (NAO)
50
How normal condtions differ from El Nino or La Nina conditions
- trade winds blow westward, pushing warm surface water towards Asia, while cooler water rises from the depths near South America through a process called upwelling
51
La Nina vs El Nino
- La Niña representing cooler-than-average sea surface temperatures in the tropical Pacific Ocean, while El Niño signifies warmer-than-average temperatures in the same region
- During El Nino, warm water goes east and during La Nina, warm water goes west
- El Nino has weak highs and La Nina has high highs
- El Nino leads to warming and La Nina leads to cooling
52
Plate Tectonic theory
- Earth is composed of numerous plates that move independently of one another at varying speeds, over the earth’s surface
- Explains how pangea could have split into the map we know today
- Convection currents drive the plate tectonic movement
53
convection currents
- movement of these causes movement of tectonic plates
- Heat from the core gives rise to these currents
54
plate boundaries
- Plates moving away from each other at divergent boundaries - rising currents of molten material moves upward and spreads laterally to form new crustal material
55
Collisions occur in these 3 ways resulting in subduction:
1. . Oceanic-continental plates
2. Oceanic-oceanic plates
3. Continental-continental plates
56
chemical weathering
- Rocks and minerals break down through chemical reactions
- A negative feedback mechanism
land masses are key in this process
- When rain or snow falls on silicate rock, it reacts and takes the CO2 out of the atmosphere
57
Milankovitch theory
- Describes the collective effects of changes in the Earth’s orbital movements upon its climate
- Milanković mathematically theorized that variations in eccentricity, axial tilt, and precession of the Earth's orbit determined climatic patterns on Earth through orbital forcing
58
eccentricity
- It varies from nearly circular to mildly elliptical due to gravitational influence from Jupiter and Saturn
- It shows an approximate 100,000 year cycle
- This changes the length of the seasons
- Favors glacier Favors inter-glacier
59
Axial tilt (obliquity)
- The angle of the Earth's axial tilt varies, approximately 41,000 years, shifting between a tilt of 22.1° and 24.5° and back again
60
axial precession
- Trend in the direction of Earth's axis of rotation relative to the fixed stars, with a period of roughly 26,000 years
- The wobble of the Earth (spinning a top)
- How close or far the earth is to the sun at different times of the year
- Impacts how warm or cold it is in the summer and winter
61
Last Glacial Maximum (LGM)
- A period in Earth's climate history when ice sheets were at their maximum extension
- During this time, vast ice sheets covered much of North America, northern Europe and Asia
62
Holocene
- A period from 11,500yr B.P. to present,
characterized by relatively stable warm climate
63
sunspot activity
- A spot or patch appearing from time to time on the sun's surface
- Can fluctuate year to year, and change all the time
64
volcanic eruptions
- They injecting sulfur-containing gases into the stratosphere, leading to the formation of liquid sulfate aerosols
- These aerosols scatter incoming solar radiation, thereby cooling Earth’s surface
- Rapid global cooling after volcanic eruptions lasts for ~ 5 to 10 years
65
global ocean circulation
- In order to balance excess heating in the tropics, the oceans transport heat (in the form of warm, fresh water) from low to high latitudes
- Warm water flows northward along the east coast of the U.S. toward Iceland
- as water moves towards the north pole, it gets colder and saltier
- this water is dense, so it sinks, and warmer surface water takes its place
66
Younger Dryas impact theory
- the Earth intersected a debris trail of a fragmented comet around 12,900 years ago
- this debris caused the Younger Dryas cooling period
- This potentially caused megafaunal extinctions and impacting human cultures at the time
67
global dimming
- A gradual decrease in the amount of sunlight reaching the Earth's surface
- Anthropogenic aerosols are major cause for this anomaly
- Global dimming in industrialized countries almost completely counteracted greenhouse warming between 1940’s and 1970’s, causing global mean temperature to remain fairly constant
68
global brightening
- Increased solar radiation received at earth’s surface
- Clean air policies in developed countries of past decades have lead to global brightening and accelerated greenhouse warming
69
key reasons for climate change
- Changes in Earth’s orbit (Milankovitch Cycles)
- Changes in solar output
- Changes in atmospheric composition
- Volcanoes/plate tectonics
- Human activity
- Changes in ocean currents
- Impact events
Smaller-scale climate oscillations (variability)
70
climate model
- a mathematical representation of the various processes that control the climate
- Need these to understand many physical processes (impact of clouds, land cover, etc)
- To stimulate and reproduce past climates, and predict future climates
- Aim to predict the mean climate state, not the day-to-day weather variations
71
general circulation models
- 3-D models that are built upon the basic equations that govern the air flows in the atmosphere and water currents in the oceans
72
climate simulation or experiment
- refers to any numerical simulation of the climate
- It can be a prediction of the mean state for the up-coming summer, a climate projection for the next few decades to few centuries, or for the past
73
ensemble simulation
- refers to a set of climate simulations with identical model setup and forcing except that each individual simulation (or run) starts from slightly different initial conditions
74
climate scenario
- a possible future climate based on scientific assumptions and models
- A range of climate scenarios are often used to quantify the uncertainties associated with these assumptions
75
climate projection vs climate prediction
- Climate projections focus on the forced climate response to future GHG increases
- Climate predictions tend to focus on the natural climate variations
- A climate predicion is a shorter-term forecast of climate conditions
- A climate projection is a long-term estimate of how the climate might change in the future based on different scenarios of greenhouse gas emissions
76
more/stronger tropical cyclones because of climate change
- Threat to people who love in coastal areas
- Thermal expansion- Ocean's water volume increases as it warms, causing sea levels to rise
- low confidence in the frequency of all-category tropical cyclones
77
arctic sea
- decreasing
- getting younger and thinner
-We will see regional temperature changes
- Greenland is thickening in the middle, but thinning at the edges
- Glaciers are retreating and discharging into the ocean
