geoengineering

Question 1

why is the 1.5C target unachievable?

Answer 1

-we’re already at 1.2C
-we would have to reduce methane levels to less than pre-industrial
-even reeducing black carbon wouldn’t produce any cooling

Question 2

what is geoengineering?

Answer 2

the deliberate large scale manipulation of climate to counteract the effects of global warming

Question 3

what are some methods of carbon dioxide removal?

Answer 3

-bioeneergy with carbon capture and storage
-biochar
-artificial trees
-atmospheric methane removal
-reforestation

Question 4

what is some methods of solar radiation management?

Answer 4

-stratospheric aerosol injection
-marine cloud brightening
-space mirrors
-surface albedo management
-cirrus cloud thinning

Question 5

why has the UK government committed to reforestation policies?

Answer 5

-easy and available
-affordable
-safe

Question 6

what does BECCS stand for?

Answer 6

bioenergy with carbon capture and storage

Question 7

how does carbon dioxide capture via BECCS work?

Answer 7

-CO2 is drawn down into trees
-biomass from energy crops, residues or waste is processed
-this is either turned into bioenergy combustion to produce energy
-or captures, transported and stored in deep geologic formations

Question 8

how is biochar produced?

Answer 8

-biomass e.g. manure, compost, organic waste, is decomposed via pyrolysis
-half goes to bio-fuel, producing energy and residual heat is reused for pyrolysis
-half gets returned to the soil as bio-char

Question 9

what are some alternative if we dont meet the 1.5C

Answer 9

-mitigation (but too little too late)
-adaptation to x8 or x16 precipitation events
-geoengineering

Question 10

what is the evidence for MCB?

Answer 10

from satellite images of ship tracks
injection of aerosol means you get smaller cloud droplets which are more reflective

Question 11

what is Marine cloud brightening?

Answer 11

spraying fine particles of sea salt provides extra CCN for cloud droplets
higher no. small cloud droplets means the clouds reflect more solar radiation back to space

Question 12

what conditions would MCB be most effective?

Answer 12

reduction in reff AND increase in LWP AND increase in cloud fraction/lifetime

Question 13

what effects did the Holuhraun fissure eruption have?

Answer 13

emitted 100kt SO2 per day
has over x10 emission rate from all 28 european countries put together
sustained for about 6 months

Question 14

what can we conclude from the Holuhraun study?

Answer 14

-emissions clearly perturb cloud effective radius
-emissions have no detectable net influence on cloud liquid water
-emissions have no detectable net influence on precipitation
-MCB may not be as effective as first thought

Question 15

how much does MCB affect amazon rainfall precipitation

Answer 15

-significantly reduce rainfall
-due to changes in large scale circulation

Question 16

what is stratospheric aerosol injection?

Answer 16

-mimics the cooling impact from volcanoes
-majority of studies suggest injecting SO2
-delivery mechanisms include high altitude aircraft, tethered balloons, rockets, artillery

Question 17

how can global mean temperatures and precipitation be kept at current levels in simulations?

Answer 17

by turning down solar constant

Question 18

what are some benefits of stratospheric aerosols injection?

Answer 18

-cool planet
-reduce sea ice melting
-reduce sea level rise
-increase terrestrial CO2 sink

Question 19

what are some risks of stratospheric aerosol injection?

Answer 19

-droughts in Africa and Asia
-ocean acidification from CO2
-ozone depletion
-no more blue skies
-less solar power
-rapid warming if stopped
-huge levels of SO2 would be needed to combat high end global warming scenarios

Question 20

what is termination shock?

Answer 20

-where stopping geoengineering would cause all the climate change at once, meaning we would struggle to adapt

Question 21

why might peak shaving be a good idea?

Answer 21

-number of european hot days can be kept down
-summer droughts can be reduced
-amount of hurricanes can be reduced
-reduce extreme climate

Question 22

what would happen if we confined commercial flights to northern hemisphere only

Answer 22

-severie drought across Sahel

Question 23

what effect would only releasing sulphur dioxide in the southern hemisphere have?

Answer 23

significant greening of Sahel