Lec 33: Mitigation to Climate Change Flashcards
What is the main driver in global climate change
Excessive addition of GHG to the atmosphere through anthropocentric activities
Adding more GHG to the atmospheric reservoir than can be naturally removed
What is Mitigation
Addressing the cause of climate change
What is adaptation
responding to the effects of climate change
What is a “wedge” (stabilization wedges)
A “wedge” is a strategy to reduce carbon emissions that grows in 50 years from 0 to 1 GtC/yr
Cumulatively, a wedge redirects the flow of 25GtC in its first 50 years
What are the 4 wedge categories (15 wedge strategies)
(4) efficiency and conservation
(1) nuclear energy
(4) fossil-fuel-based Strategies
(6) Renewables and Biostorage
What are the 4 wedge strategies of Efficiency and Conservation
- Transport efficiency
- Transport Conservation
- Building Efficiency
- efficiency of electricity production
What are the 4 wedge strategies of Fossil-Fuel-based
- Fuel switching (coal to gas)
- Fossil-based electricity with carbon capture and storage (CCS)
- Coal synfuels with CCS
- Fossil-based hydrogen fuel with CCS
What are the 6 wedge strategies of Renewables and biostorage
- wind-generated electricity
- solar electricity
- wind-generated hydrogen fuel
- biofuels
- forest storage
- soil storage
Transport efficiency
1 wedge = fuel efficiency of all cars was doubled from 30 mpg to 60 mpg
efficiency improvements: Hybrid and diesel engines, making vehicles out of stronger, lighter material
There is a total energy loss of 75-82% in gasoline vehicles (which is huge!)
Transport conservation
1 wedge= number of miles travelled by the world’s cars were cut in half
Urban planning leading to more use of mass transit and if electronic communication becomes a good substitute for face-to-face meetings
Building efficiency
1 wedge = if emissions in all new and existing residential and commercial buildings were cut by 25%
Largest potential savings are : heating and cooling, water heating , lighting and appliances
Carbon savings from end-use efficiency strategies (wall and roof insulation), renewable energy strategies (solar water heating passive solar design)
Fuel-Switching for electricity
1 wedge = if 1400 large (1 billion watts) natural gas plants displaced similar coal-electric plants
Because of lower carbon content of natural gas and higher efficiencies of natural gas plants -> 50% emissions of from coal
wind electricity
1 wedge= if current wind capacity scaled up by a factor of 10
currently produces 2% of total global electricity
requires 1 million large windmills (area of Germany)
growing rate of 30% per year
Solar electricity
1 wedge = if installed solar arrays with an area of two million hectares (20 000 Km2)
convert sunlight to electricity, CO2 free and renewable
lower land demand than other renewables
currently provides less than 4% of total energy
Nuclear electricity
1 wedge = if the world’s current nuclear capacity by nuclear electric plants was tripled
currently provides 10 % of the world’s electricity, no CO2, world’s second largest source of low-carbon power
1960s global installed nuclear capacity of about 2000 billion watts was projected by 2000 - now only 1/6 (if done = 2 wedges)
what are the safest and cleanest sources of energy ?
Wind, Nuclear and solar
Forest storage
1 wedge = if global deforestation was stopped
current global deforestation adds 1-2 billion tons of carbon to atmosphere
“natural sinks”
Requires reduction in deforestation + planting new trees
geoengineering frame works:
carbon dioxide removal
increasing global or local albedo
give some examples of bioengineering proposals
- Increased reflectivity from low clouds (by spraying sea salt into them)
- thinning high clouds (clouds act as a blanket, retaining heat)
- ocean fertilisation (increasing population of carbon-absorbing plankton)
- Increased reflectivity from the oceans (microbubbles increase reflectivity)
- Biochar (carbon-rich charcoal from burnt crops added to soil)
- Direct capture and storage of CO2
- Afforestation
…
Stratospheric aerosol injection
Intentional injection of molecules which interact with, and reflect shortwave solar radiation in the atmosphere
an exemple of stratospheric aerosol injection ( that has happened)
The year with no summer due to the mass release of SO2 from volcanoes
Does SO2 interact directly with shortwave radiation?
No it interacts with Hydroxyl, water and oxygen molecules, forming sulfuric acid droplets wich do interact and reflect shortwave radiation
T or F: Aerosol suspension in the atmosphere is temporary
TRUE
what is aerosol masking
The reflection of incoming solar radiation by aerosols (man-made and natural)
(like a layer of dirty insulation)
what is marine cloud brigthening:
Generate more, longer lasting, high-altitude clouds over marine environmnets through the injection of sea salt particles into the air
(Based on observations that aerosols in ehaust of modern marine shipping leaves trails (ship tracks) which induce the formation of clouds)
Refreezing arctic sea ice
water from the arctic ocean is pumped onto thin arctic ice, allowing the water to freeze and thicken the ice layer
Ocean fertilization (and its process)
Utilizing the biological pump of the ocean to sequester carbon in the sediment layer
Process:
Add one or more nutrients to stimulate growth in the trophic level which uptakes dissolved carbon from the water ( phytoplankton and algea)
Increase in algea / phytoplankton = increase in carbon which enters the biological pump
and ultimately enters the sediment layer in the ocean
what are the potential issues with ocean fertilization
overfertilization causing shifts in food webs or eutrophication
Carbon capture
Direct capture and storage of carbon
atmospheric carbon is removed from the atmospheric reservoir, and incorporated into long term storage in commercial products or the rock layer
what are the considerations to have regarding geoengineering?
who gets to decide how things are implemented?
some countries will likely experience weather disruptions, how will the be compensated?
what is we make things worse?
The main barrier is how to scale
