biol 1052 midterm 4 / final exam

global climate change inflkuences

atmospheric science, physics, biology, meteorology, biogeochemistry, climatology, chemistry, computer modeling, math

what influences our perceptions of climate change

- peoples beliefs increases when it's warmer

- beliefs are specific to political affiliation

climate

the conditions in the atmosphere over relatively long periods of time

weather

the condition of the atmosphere over relatively short periods of time

global warming

warming of the planet, based on average temperatures

climate change

changes in climate characteristics (temp., precipitation, humidity, storm frequency)

global weirding/climate destabilization

observations of unusual weather patterns

recent history

- global temperatures have an increasing trend line

- it doesn't warm up every year, but overall increases

increased urbanization

weather stations are affected (temperature)

actual measurements

thermometers, satellites - take ocean and air temperatures at many locations

proxies

don't give actual measurements, but give data that can be extrapolated to temperature estimates

proxies examples

- coral reef layers

- borehole temperatures

- tree rings

- isotope ratios

when would we be least likely to find concern about climate change to be higher than normal

cold day in april

data from past 200 years say...

temperatures have increased over time

distillery

how we got temperature estimates from 400,000 years ago

which type of water would be more likely to evaporate

water with only light isotopes

as water travels to poles while evaporating

heavy isotopes will fall out first as rain/snow

when is there more energy in the atmosphere?

when the earth is relatively warm

ice caps

enriched for light isotopes

ocean

enriched for heavy isotopes

sea creatures

enriched for heavy isotopes

if someone were to find a layer of ice with lower than average heavy.light isotope ration

the temperatures would have been cooler than average

cause of cc - end of last ice age theory

not supported by data

cause of cc - solar flares theory

not supported by data

cause of cc - increase in greenhouse gases theory

most likely

ice age causes

- milankovitch cycles

- eccentricity

- obliquity

- precession

milankovitch cycles

changes in earth's orbit and orientation towards sun

eccentricity

orbit

obliquity

tilt

precession

wobble

without the greenhouse effect, earth would be

-18 C

what is the cause of historical periodic ice age

alterations in the earth's orbit and orientation to the sun

greenhouse gases

absorb infrared radiation (heat)

during warm global temperatures, the polar ice caps are

smaller

heavy/light ratio during warmer global climates at the poles

larger

heavy/light ratio in marine sediments during warm temperatures

lower

most abundant gases in earth's atmosphere

N2 and O2

other 1% of gases in atmosphere

argon, greenhouse gases, other trace gases

greenhouse gases examples

methane, nitrous oxide, ozone, carbon dioxide, halocarbons, water vapor

ocean and carbon dioxide

takes it up

during cool temperatures, how many isotopes fall back at poles

more

oceans

huge carbon reservoir

seasonal fluctuations

summer in northern hemisphere = a lot of photosynthesis

where do fossil fuels originate

plants - when burned, are depleted

12C carbon

stable, plants take up

13C carbon

stable, proportion has been declining

14C carbon

radioactive, taken up through photosynthesis

most important greenhouse gases

co2

second most important greenhouse hases

nitrous oxide and methane

National Academy of Science

job is to provide independent objective advice to nation

IPCC - international panel on climate change

members government nominate authors

positive feedback loops

the effect of a change furthers the change, causing even more change

negative feedbacks in climate change

earth warms slightly, increased evaporation causes increased low clouds, earth cools slightly

plants influence atmospheric co2 composition via...

reductions of co2 due to photosynthesis

heat waves

temp changes greatly during winter

ice melts

sea levels rise, increased human migration

precipitation changes

northern north america = more rain

storm frequency/intensity

more storms as temps increase

changes in ranges and distribution

can lead to mismatches in seasonal timing among species within an ecosystem

phenology

timing of activities (migration, nesting, etc.)

changes in human population distribution

- sea levels rise

- infiltration of salt water into fresh water

- increase in storm and flooding

- desertification

agriculture

- growing seasons lengthen

- crops already near climate thresholds will suffer decreases

- water issues

warming will occur more on land

during winter and at poles

european heat wave of 2003

more likely due to human activities

nonrenewable

fossil fuels, nuclear

renewable

- geothermal

- solar

- wind

- hydroelectric

- biofuels

- tidal/wave energy

ANWR (Arctic National Wildlife Refuge)

ecologically unique

what percentage of u.s. energy comes from nuclear power?

8%

nuclear reaction - positive or negative feedback?

positive feedback

nuclear power

- cleaner than fossil fuels

- radioactive waste

- accidents

- high rates of thyroid cancer

- problems with contaminated milk

EROI - energy returned on investment

- nuclear = 14:1

- coal = 46:1 (high payoff)

- natural gas = 20:1

wind energy

turbines convert wind to electrical

wind energy pros

no emissions, get a lot of energy for investment, can be small scale

wind energy cons

some areas windier than others, may need to transport from wind farms to cities, threats to wildlife

where do most co2 emissions come from?

china

paris agreement goals

keep warming below 2 degrees C, zero net emissions by 2nd half of century, rich countries fund 100 billion/yr to poorer countries

paris agreement parts not legally binding

emissions reduction agreements, financing, no u.s. or european liability for effects

paris agreement parts legally binding

5 year review cycle, must set goals for c-reduction, must be transparent in monitoring and reporting

u.s. federal regulation

energy independence and security act of 2007 raised vehicle efficiency standards

EPA's role

supreme court ruling said that greenhouse gases are air pollutants that fall under the clean air act

cap and trade

government can reduce number of permits each year to reduce greenhouse gas emissions

carbon tax

tax on fossil fuels

- will drive businesses to be more efficient

- might be simpler and faster

- consequences in terms of cost and energy