Defiant Earth

Question 1

how have humans influenced the carbon cycle?

Answer 1

burning fossil fuels, land clearing, burning off

Question 2

atmospheric carbon dioxide levels have increased

Answer 2

so have surface temperatures

• surface has increased by 1 degree
• higher latitudes have warmed more than near the equator

Question 3

greenhouse gas

Answer 3

a gas in the atmosphere that allows incoming solar radiation to reach the earth’s surface, but absorbs raditation re-emmitted as heat, trapping it in the atmosphere and causing temperature to rise

• more greenhouse gas = more trapping
• CO2, water vapour and CH4 (archaeons in cows and rice paddies release, thawing permafrost)

Question 4

temperature predictions

Answer 4

will increase 2-5 degrees over 21st century

Question 5

what does measuring salinity of water show?

Answer 5

balance of rain and evaporation shows that dry areas are becoming drier and wet areas, wetter

Question 6

changing environments affects species distributions

Answer 6

• extinctions
• evolve in response to climate but not fast enough for anthropogenic change
• migration - animals and plants (seed dispersal) interupted by cities (assisted migration)

Question 7

coral reefs

Answer 7

unicellular algae live in coral and provide nutrients
corals form skeletons of calcium carbonate
high temperatures cause algae to leave, killing coral - also facilitates spread of infection

Question 8

ocean acidification

Answer 8

carbon dioxide becomes carbonic acid in water, increasing acidity
pH dropped 0.1 units (30% increase in H+)
carbonate ions decrease, making CaCO3 skeletons hard to make
pH to 0.8 by end of centuary - coral might not survive

Question 9

CO2 levels

Answer 9

315ppm-400ppm in last 50 years

CO2 to 500ppm by end of centuary

Question 10

evidence for climate change from IPCC

Answer 10

• increased surface, atmospheric and ocean temperatures

- shrinking glaciers, decreased snow - rising sea levels and increased water vapour

Question 11

cryptosphere

Answer 11

all regions where water is solid - being melted/less heat reflected

Question 12

has climate change happened like this before?

Answer 12

mean N Hemisphere temp over 30 years has exceeded any previous 30 year mean in 1400 years
this is different

Question 13

forcing

Answer 13

any factor that influences global climate by heating or cooling the planet
- volcanic eruptions, solar variations, anthropogenic changes have most influence

Question 14

energy balance

Answer 14

• heat from the sun is reflected ir absorbed and scattered
• greenhouse gases - less energy leaving than enterning - imbalance
• heating results
• energy budget: some gained, some lost

Question 15

observed changes

Answer 15

• aquatic species - changed behaviours, abundances
• water - changing precipitation, melting
• sea levels rising
• ocean circulation changes
• ocean acidification
• extreme weather
• human conflict over resources, displaced people

Question 16

biodiversity responses to climate change

Answer 16

• adaptive evolution - help occupy new niches
• phenotypic plasticity
• migration (range shifts)
• tolerance - just deal with it by phenotypic plasticity or evolution

Question 17

knowlege gaps - range shifts and tolerance

Answer 17

• how fast can species migrate? how far? which species?

- what are the relative roles of evolutionary adaptation, phenotypic plasticity and dispersal?

Question 18

geoengineering

Answer 18

using large scale engineering to alter climate

Question 19

carbon dioxide removal

Answer 19

reducing atmospheric carbon dioxide

Question 20

solar radiation management

Answer 20

increasing reflection away from earth

Question 21

terrestrial CO2 removal

Answer 21

• afforestration/reforestation
• bioenergy with carbon capture and storage (high priority - can make fuel)
• biochar
• enhanced weathering: base materials to land or in situ
• direct air capture (high priority)

Question 22

marine CO2 removal

Answer 22

• ocean fertilisation: iron or nitrogen and phosphorous (high priority)
• enhanced upwelling/downwelling
• biomass storage in ocean
• enhanced weathering: base materials to ocean

Question 23

atmospheric/stratospheric dimming techniques

Answer 23

• sunshades
• stratospheric sulphate aerosol injections (high priority)
• enhanced marine cloud albedo (saltwater spray - high priority)

Question 24

earth’s surface reduction of radiation

Answer 24

• enhanced desert albedo
• enhanced cropland/grassland albedo
• enhanced urban albedo

Question 25

ranks

Answer 25

SRM are ranked more highly generally