part 2 Flashcards
stages of deep history of climate
- margine life diversifies in extreme heat
- land plants develop and absorb CO2
- polar ice caps form
- volcanoes and erosion cause CO2 level cycling
- mammals eveolve
- recent claciations and rapid warming in Holocence/anthropocene
Gaia hypothesis
idea by lovelock on marguilis that earth’s systems self regulate, non-living and living systems feed into eachother
what is a hothouse
period of global warm temperatures (without ice caps), most severe at poles
basis for gaia hypotheses
earth’s temperature stays within a narrow range for past 3.6 Ga despite increase in solar intensity by 25%
dasiyworld model
model by lovelock and watson that showed how daisies with different albedos regulate the temperature/are regulated by temperature
climatic optimum
5.5-9ka when temepratures were warmer, had the greatest amount of solar luminosity
end of the younger dryas
time after 11.6 ka, end of a cold event
what period are we currently in
neoglacial period (since 5ka), post little ice age, more glacial advances than previous years
how does treeline change with climate
higher treelines indicate warmer climates (higher during holocene optimum compared to now)
climate variability over past 1500 years
2 cool, 2 warm periods: dark ages, medieval warm period, little ice age, modern global warming
mean annual solar insolation at TEA
340w/m^2
variation in irradiation
400 @ equator
190 @ poles
how much have milankovitch cycles affected radiance
up to 25%
solar constant/radiation if earth was a disc
1360w/m^2
what causes runaway warming/cooling
when incoming shortwave radiation does not equal outgoing longwave radiation
what are some factors that decrease absorbed radiation at the surface
backscattering from air, absorption from water vapor/dust/ozone/clouds, reflection by clouds/surface
how does the greenhouse effect work
shortwave passes through co2, but longwave (outgoing) excites it and reflects it back to earth
what do plancks curves show
that when CO2 goes from 300-600ppm there is a difference in absorption of 3.4w/m^2
when does co2 increases have the most effect
lower levels of co2
how to compare greenhouse gases
radiative force: gas characteristics, abundance, indirect effect
water vapor and clounds greenhosue effect
largest greenhouse effect, short cycling times, positive feedback loop with increased temperatures
breakdown of radiative forcing
50% water vapor
25% clouds
20% co2
5% other gasses
natural sources of radiative forcing
cyclical varations in solar activity, volcanic activity (short term cooling effect
why is CO2 such a concern
despite having a low atmospheric composition 0.04%, it has major role in warming, intertial/long cycling –> future warming, high rate of growth
mauna loa CO2 levels
275ppm (ice core), 315 in 1958, 420ppm today
range of co2 levels in past 800ka
180-275ppm (higher in history)
per capita co2 emissions
15 ton per person in canada
what is gis
geographical information system
georefrenced data
it must be possible to relate data points to a location
vector vs raster points
vector: discrete features
raster: continuous phenomena as a regular grid of cells
increase in temperature from 1900
1.5C warmer today, land (2) warmer than oceans (1) because of thermal lag
issues with historic climate records
geographic bias, high extrapolation pre 19000
warming bias from urbanization
90+% of weather stations dont meet citing requirements, leading to artificially warm temperature
urban heat island effect
3C warmer in cities than rural because of concrete and no tree cover
satellite vs weather station climate anomaly
0.13/decade vs 0.16/decade
climate anomaly since pre-industrial times
1-1.5 varied by region
global dimming
sulfate reduce expected climate warming by blocking solar heating
arctic amplification
climate warming is greater at higher latitiudes/altitudes because of positive feedback from seaicemelt and air warming because of ice albedo
- up to 4C higher
sea ice extent
september is when sea ice is lowest, most ice now is annual ice
high altitude amplification
pver past 20y, 75% faster warming amove 4000m because of snow beds
why especially high temperatures ince 2022?
hunga tonga erruption increasing water vapor by a TON
global greening
increased warming and CO2 increase plant growth
why has cereal production increased
innovation (green revolution), and increases in CO2 –> increased yield
GCM
general circulation model/global climate model)
- uses navier stokes equations and thermodynamics for simulation earth’s environment
- weather and climate change forcasting
IPCC
group within the UN for physical science, impacts adatpation & vulnerability, nad mitigation. that crease assessment reports
coupled model intercomparison project
uses standard GCMs, couples areas of earth’s climate to model climate change
represenetative concentration pathways
different trajectories of GHG emissions and climate change
RCP 8.5
warmest future, no mitigation
RCP 6.0
moderate mitigation, uses technology and strategy for reducing GHG emission
RCP 4.5
moderate mitigation
RCP 2.6
mitigation, low greenhouse gas concentration, “peak and decline” scenario
potential ssps
sustainability, middle of the road, regional rivalry, inequality, fossil fueled development
most likely scenario
SSP 1/2; RCP 2.6-4.5
how are uncertainties among GCMs accounted for
Ensembles: average of multiple models
challenges in projecting GHG based climate models
estimating population growth, energy use, geopolitics
changes in clobal fertility rate/ canadas fertility rate
more than halved since the 60s. canada currently at 1.33
net zeo pathway investment
2.4 trillion/yr USD to 2035
bulls eye effect
increased urbanization/expanded city causes more economic damages from the same flood
velocity of climate change
how fas tyou need to migrate to maintain the same climate (also affected by terrain)
how to assess climate risk for a species
climate velocity x habitat fragmentation
climate change refugia
areas of stable paleoclimates/escape climate (historically) or areas that will be more stable in the future/lowclimate change velocity
energy flow through trophic levels
only 10% energy retained as you move up a level –> less biomass at the top
bioaccumulation
toxins are accumulated at higher levels, higher tropic levels have higher concentrations of toxins
green world hypothesis
predators reduce the abundance of herbivores, allowing plants to fluorish (top-down control)
Barro colorado island
tropical research area that was connected to the mainland prior to the panama canal
terbourgh
The big things that run the world. examined trophic cascades and the loss of groundbirds on BCI, then in venezeula
effects of trophic cascade in venezeula
loss of vegetation, increase in certain species of ants, thorny vines kill trees
wolves in yellowstone
wolves extripated 1926–> incerase in elk –> impacs on trees (reduced species, numbers)
wolves reintroduced 1995
generalizations of trophic cascades
apex prdators control hyper-abundant herbicores, apex predators can be irrelevant, systems with larger herbivore populations can be sensitive to predator losses
biosphere
place on earth where life dwells, sum of all living organisms, closed/self regulating systems
biomass proxy
proxies like chlorophyll/remote sensing/normalized difference vegetation index quantifies amount of green plants to determine the prodcution of a biosphere
holdridge’s life zone
three axes: precipitation, biotemperature, potentiall evapotranspiration ratio, organized in a triangle
whittaker’s biome
biome classification using MAP and MAT
whittaker’s ecosystem uncertain
vast areas of non-forested vegetation occurs where climates are suited for forests, why?
Bond’s ecosystem uncertain
areas of the wrold are consumer controlled (biotic consumers, fire as an abiotic consumer), leading to unforested areas
ecoregions
information on local soils and landforms, increasing detail based on level
disjunct genera
large number of shared genera between areas that are not geographically close
Gray’s hypothesis
suggested that there was a closer relationship between EAS and ENA than ENA and WNA (now disproven)
key glacial refugia in ENA
southern appalachia to gulf coast
western refugia
more complicaed because of mountains/deserts
reids paradox
mismatch of theoretical and actual migration rates (esp holocene postglacial)
explanation of reids paradox
occasional, long distance events are probably due to active dispersal
examples of reids paradox
oaks migrate faster than other eastern deciduous because of larger seeds
rapoport’s rule
ranges of plants and animals increase with latitute
bergmanns rule
body size of animals increases in colder environments (thus with latitude)
factors that limit range of a species
abiotic - climate (high latitude), and biotic - competition (low latitiude)
grinellian niche
ecological role of the specieas –> their habitat and adaptations to it
eltonian niche
a species’ place in the biotic environment (trophic levels)
hutchinsonian niche
ecological space occupied by a species –> where would this speices have poitive growth rates
types of hutchinsonian niches
fundamental, potential, realized
fundamental niche
all of the possible conditions where a species could persist
potential nice
intersection of the fundamental niche and the climatic space
realized niche
segment occupied by the speices (accounts for biotic interactions and dispersal)
niche conservatism
retention of niche related ecological traits
what must species with strong climatic nc do
migrate or go extinct, critical in response to climate change
BAM venn diagram approach
biotic, abiotic, movement domains to a niche sapce, compares favorable biotic encironments, physiological requiements, and accessible habitat
eltonian noise hypothesis
abiotic and biotic niches are roughly equal. allows to model species distribution with climate change without considering biotic relationships
hutchinsons duality
species occupy geographic and environmental spaces
- one g-space only has one e-space
- an e-space can have many g-spaces
