Bieb 140 Lecture 14

incidence energy, from sun,

is the balance of what goes in and what goes out

about 25% is absorbed, 75% reflected back to space, changing the 23 % leads to climate change

eccentricity: shape of orbit

obliquity: tilt of earth's axis

Precession: earths wobble

this three parameters change with time leads to climate change

glacial and interglacial cycles

gases in atmosphere absorb infrared light

Jean Fourier , basic physics

Arrhenius , provided first temp estimates

CO2 accounts for only 50% of greenhouse effect

rest s from methane and freon traces

average temp on earth is getting hotter

methane is much more powerful greenhouse gas than CO2

methane is mostly frozen , raising temp !

Local climate change is not predictable

what parameters go into models, anthropogenic and natural forces

CO2 emissions , future Co2 projections based on human useage of fossil fuels

EMISSIONS based on human behavior

increase co2 , affects physiological, phenology, distribution of species , in turn affects species interactions and in turn affects extinction , speciation, composition of communities will be very different , change in biota

study of temporal aspects of natural recurrent phenomenom and their relation to climate

egg-laying,

flowering, leaf fall

hibernation

transition from larvae to adult

migration

not record for phenology, it is an obervation

phenologies of some temperate species is controled by photoperiod (length of day) not changed by temp change.

Anerican robin, winter temp change , shortens ,

migrate to breeding ground early ,

temps in northen latitudes are changing at different rates than lower latitudes

mismatching in timing of phenological shifts can disrupt species interactions

in early winter moth mates female lays eggs

eggs have diapause, hatch in Feb , if hatch too early, caterpillars will starve , if after bud burst less eatable leaves are available

reptiles, female lay eggs, temp determine sex, sex ratio is dependent on temp

tuatara= as temp gets hotter, more females, leading to decline of population

range moves north , to higher latitudes

different species moves at different rates. but not all species shifts.

changes , local extinction- recolonization

fossil pollen, sheep ranges of nevada

small mammals in Yosemite

species range contracts upward with high temp

each species range shift is individualistic

based on physiolocial changes

community level changes

clements , ecologist, argued that when climate changes the community they respond in a cohesive manner

communities of super organisms that respond cohesively

species respond individualistic to climate change. communities represent a shared tolerance that happen to intersect at a given time

they respond to climate change based on their physiology, biology,

shifts are individualistic

communities are reshuffled

sample mud seperate pollen , identify and count

gives you relative abundance of species at that time , carbon dating dates the core + sample

corroborates Gleason model

if you go back 6,000 years ago

lush vegetative place

supported by climate model

it was wet and lush , no desert

also supported by rock art , people diving into water

use enivironmental distributions of species

and their physiology to predict new distributions under climatic conditions

advantages

can use for any species( climate Envelope)

max temp min temp, it can exist

then apply new scenario to climate envelope

all you need is range map and environmental data

disadvantages

data limitations: except for few species, no god data for range map, climate envelope will not be accurate

too simple: we do not know physiology for all species

assumes no adaptation of species

some species have been shown to adapt

micro and mesocosm

are restricted to plant communities, hard to tract animals,

:heat things up , pump CO2 into canopy,

changes in soil to communities

changes in precipation

advantages :

easy to manipulate, temp co2 nitrogen

test for different combinations of these factors

disadvantages:

logistical constraint , must distribute over small areas over globe

hard to extrapolate, apply results to whole ecosystems

what happens to associated species

GOOD ONLY FOR short lived plants

comparative approach look at responses over gradients, co2 , temp, nitrogen

based on results you can build statistical models

if you change the temp this way or that you can predict what will happen to species based these historic gradients

adavantages:

large spatial and temporal scales

disadvantages :

nonexperimental

data limitations

hard to seperate environmental change from other anthropegenic change

non analog communties: there is no analog of past communites today , they have obviously changed. and if the current communtiy is unique, statistical model may not be able to predict changes accurately

as we destroy habitats, will there be habitat for species to move into?

small herbivores, live in very high altitudes,

restricted habitat. may run out of habitat

great basin has extinct populations

oceans absorb CO2

the other CO2 problem

half of anthropogneic CO2 is absorbed by ocean

ph will drop by 0.5untis by 2100

Will cause species with calcified shells to decline, they will not be able to grow, precipitate their exoskeletons

pH is not stable across ocean, why ?

pH not same across ocean because of upwelling , cold water tend to be lower in pH

how does changing chem in ocean affect animals

declining pH of intertidal community

tidepools pH testing, they varied substantially

they tested pH during night and day,

to account for local CO2, net effect the pH is declining

short term microcosm exp.s showed mix results: increased mortality, and reduced calcification , some show increase, while others show no effect

new diseases as ranges shift

cholera and el nino

vector diseases,

as temp goes up, vibrio cholera, range increases

microbe is sensitive to ocean temp

tight correlation to sea surface temp and cholera outbreaks, as seen by stats

strong correlation with high precipitation

and incidence occurance

mosquitos range changes also