Climate Change

Question 1

Global warming/climate change

Answer 1

increased warming of global temperatures

Question 2

human-enhanced greenhouse effect

Answer 2

human activities since IR led to increase of CO2 which has led to increasing global temperatures, 47% increase of CO2 in atmosphere, increase in methane + nitrous oxide, use of CFCs

Question 3

Intergovernmental Panel on Climate Change (IPCC)

Answer 3

anthropogenic factors almost entirely responsible for climate change
concluded that since 1951-2010 more than half of increase in global temperature caused by humans

Question 4

Dendrochronology

Answer 4

study of dating past events using tree rings
useful for establishing dates of catastrophic events + identify periods of drought + lower/higher temperatures

Question 5

Oxygen Isotope Analysis

Answer 5

ratio of 18O & 16O in water + calcium –> tells what environment it was formed in
ice + glaciers have more 16O which is returned to oceans when it melts

Question 6

Ice Cores

Answer 6

Can analysis ratio of 18O to 16O.
Act as thermometer for ocean (more 18O evaporate when ocean temps low) so ratio of 18O : 16O gives insight into temp
provides info on composition of atmosphere –> air bubbles get trapped into ice which u can measure CO2

Question 7

Dome C

Answer 7

location in Antarctica w. thickest ice cap –> get information on atmosphere back 800K years, shows that present concentration of CO2 now is highest it has ever been

Question 8

Pollen Analysis

Answer 8

Radiocarbon dating of pollen in lake bottoms/bogs –> give relative amount of 14C + 12C –> indicates how long ago plant/animal alive
prevalence of which type of plant (ones which thrive in cold vs ones which thrive in warmth) –> indication of environment there

Question 9

remnant glacial landforms

Answer 9

glaciers leave marks on landscape
- Striates bedrock = shows height of past glaciers
mounds of unsorted rock called moraines at edges of glaciers –> used to determine original extent of ice + glacial retreat over last century

Question 10

Spleleothems

Answer 10

calcium carbonate –> leaves “growth rings” in stalagmites + stalactices –> combined with isotopes of carbon/oxygen give info on precip + temperatures when spleothem formed

Question 11

Causes of climate change

Answer 11

1) atmospheric aerosols
2) fluctuations in solar output
3) variations in earth-sun relations
4) greenhouse gas concentrations

Question 12

atmospheric aerosols

Answer 12

large quantities of particulates ejected into atmospheric can alter global temperatures
ex: volcanic ash can go in atmosphere + block solar radiation for long time
sulfates = lead to cooling bc they scatter incoming solar radiation
black carbon emissions = absorb solar radiation leading to warming

Question 13

Fluctuations in solar output

Answer 13

periods of reduced solar sun flairs –> lead to unusually cold weather on earth
connection between sunspot cycles + climate may be strong statistically BUT many scientists unconvinced

Question 14

Greenhouse Gas Concentrations

Answer 14

Greenhouse gases (Water Vapor, CO2, CH4) cause warming
Strong link btwn increase in CO2 + fossil fuel use
now atmosphere has less 14C compared to IR –> shows that the additional CO2 came from “old” carbon sources –> coal, petroleum

Question 14

Variations in Earth-Sun Relations

Answer 14

Eccentricity of orbit = changes between eliptical + circular –> leads to variations in insolation

Obliquity of rotational axis = varies from 22.1 - 24.5, when inclination is higher = seasonal variation btwn high + low latitudes is greater

Precessions: Earth’s axis wobbles so it does slightly point in diff directions over 25000 year period. ALTERS TIMING OF SEASONS

Milankovitch: times when significantly less insolation hits earth –> leading to smaller contrasts between winter + summer

Question 15

Positive Feedback mechanism

Answer 15

Global climate cooling –> ice expanding –> more cooling –> more ice
Global warming –> ice shrinking –> more warming –> less ice

Question 16

What is complicated about water vapor positive feedback loops

Answer 16

Warmer temp –> more water evaporates –> more water vapor –> more heating bc it’s greenhouse gas
BUT watervapor also produces clouds –> reflect incoming radiation
depends on which types of clouds that are formed bc diff clouds have diff albedos

Question 17

Observed Climate Change Air Temp

Answer 17

Air temp = increase by more than 1 C

Question 18

Observed Climate Change Ocean

Answer 18

Ocean = certain upper 700 meters ocean warmed + that 90% of extra energy stored in ocean –> leading to increased ocean acidity + melting sea ice –> increase ocean levels

Question 19

Observed Climate Change Polar Region

Answer 19

Polar Regions = ice sheets heated more than average, that Antarctica/Greenland lost mass, sea ice declined by 3-4% a decade

Question 20

Observed Climate Change Weather Patterns

Answer 20

Weather patterns = extreme weather patterns more common

Question 21

Observed Climate Change Biosphere

Answer 21

shifts in geographical ranges, migration patterns for many animal species
negative crop yields from climate change

Question 22

Future Climate Change Temperature

Answer 22

Projected:
increase in .3-.7 C by 2035
certain hot temperatures become more frequent

Question 23

Future Climate Change Ocean Projections

Answer 23

ocean continue to warm + sea levels will continue to rise by 2 mm for 95% of ocean area

Question 24

Future Climate Change Polar Region Projections

Answer 24

High confidence Arctic region will warm more rapidly than world
ice sheets will decrease by 15-85%
permafrost will decrease

Question 25

Future Climate Change Weather Pattern Projections

Answer 25

precip changes NOT uniform around world
1) high latitudes, midlatitudes will have MORE precipitation
2) midlatitude, subtropical dry DECREASE in precipitation
3) precip will become more extreme + intense over most midlatitude + wet tropical

Question 26

biosphere changes

Answer 26

1) high confidence that many species face increased extinction rates
2) many animal/plants will not adjust ranges quick enough to adapt to climate changes
3) increased ill health among humans, especially in low-income
4) increased food insecurity

Question 27

Milankovitch cycles

Answer 27

Milankovitch cycles are a series of changes in the Earth’s orbit that affect the climate over thousands of years
THREE TYPES
1) Eccentricity - shape of Earth’s orbit
2) Obliquity - tilt of Earth’s axis, greater tilt = more severe seasons
3) Precession - direction of Earth’s rotation, full precession every 26K years