7 - Geoengineering Flashcards
(17 cards)
What is geoengineering?
The deliberate large-scale intervention in the Earth’s climate system in order to moderate global warming
What are some issues of geoengineering?
Ways of intervention
Feasibility
Uncertainties
Effectiveness, costs and environmental impact
Governance and public acceptance
Name the two types of geoengineering strategies
Carbon dioxide removal(CDR) techniques - addresses the root of climate change by removing GHGs from atmosphere
Solar radiation management(SRM) techniques - only attempts to offset effects of increased GHG concentrations by increasing albedo - does not solve root of issues
Name some examples of CDR techniques.
Pumping liquid CO2 to deep sea/into rocks
Iron fertilisation of sea
Name some examples of SRM techniques.
Stratospheric aerosols
Cloud seeding
Cloud brightening
Describe the process of cloud seeding
(Latham, 1990) - mainly involves increasing the droplet concentration of clouds by introducing more cloud condensation nuclei to the atmosphere
What are some positives of cloud seeding?
On a large scale, it has the potential to significantly reduce global mean temperature
Leads to regional changes in temperature and precipitation - increased rainfall in sub-Saharan Africa and Australia(Jones et al., 2009)
What are some negatives of cloud seeding?
Balance of warming would require a 15-20% increase in C amongst other factors(Lathum, 1990)
Could exacerbate global warming - potential negative impacts on the Amazon, which is a major sink for carbon dioxide(Jones et al., 2009), & disrupting the Amazon would result in extreme changes in climatic cycles
Also extremely difficult to coordinate between various countries
Describe some issues of Carbon Capture and Storage(CCS).
Only applicable to large sources & storage effectiveness is questionable - may be inefficient
Describe the process of ocean storage.
Fixing a pipeline from the power plants to bodies of water - this results in more ocean acidification with gaseous or liquid CO2 being released from the pipeline & the liquid CO2 creating lakes along the ocean surface
May created CO2 lakes along ocean surface which are uninhabitable
Describe the process of geological storage.
Involves pumping gas downward into the Earth(e.g. in oil fields where infrastructure already in place)
Long term storage is limited by diffusional loss and tectonic stability - 1% loss rate
Describe the climate effects of aerosols.
Direct effect - net cooling as aerosols scatter and absorb radiation
First indirect effect - cooling as aerosols increase number concentration of cloud droplets and ice particles
Second indirect effect - cooling as aerosols decrease precipitation efficiency
Other indirect and semi-direct effects - cooling/warming
What are some positives of stratospheric aerosol injections?
Only 2-4% of the mass of current sulfur input is needed for this to occur
Relatively cheap - $25-50 per capita in the developed world
(Crutzen, 2006)
Allows for smaller carbon dioxide removal strategies to take place whilst significantly influencing global temperatures
Research based in volcanic eruptions strengthens its reliability
What are some negatives of stratospheric aerosol injections?
Stratospheric ozone effects – Mt Pinatubo resulted in the largest ozone hole over Antarctica in recorded history(Self et al, 1993)
Feasibility of various countries aligning on such an expensive scheme
Method of aerosol injection uncertain - potentially release of soot particle(would reduce albedo but also would reduce surface temperatures)
How did Mount Pinatubo demostrate the climatic effects of aerosols?
The volcanic aerosols in the stratosphere excites the positive phase of the NAO - differential heating between low and high latitudes in stratosphere, strengthening of polar vortex in winter, planetary waves reflected back to troposphere, circulation pattern with warm air advection over NH continents
Therefore, overall tropospheric cooling although warming possible in some regions
(Self et al., 1993)
Contrast CDR and SRM.
SRM cheaper & fast to implement although it does not address ocean acidification and affects both the hydrological cycle & atmospheric circulation
Name an example of how geo-engineering has influenced interest in eruptions and their climatic effects?
(Budyko, 1974) - proposed idea of burning sulfur into the atmosphere to reverse global warming because it would create a reflective haze ‘much like that which arises from volcanic eruptions’
