7 - Geoengineering

Question 1

What is geoengineering?

Answer 1

The deliberate large-scale intervention in the Earth’s climate system in order to moderate global warming

Question 2

What are some issues of geoengineering?

Answer 2

Ways of intervention

Feasibility

Uncertainties

Effectiveness, costs and environmental impact

Governance and public acceptance

Question 3

Name the two types of geoengineering strategies

Answer 3

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

Question 4

Name some examples of CDR techniques.

Answer 4

Pumping liquid CO2 to deep sea/into rocks

Iron fertilisation of sea

Question 5

Name some examples of SRM techniques.

Answer 5

Stratospheric aerosols

Cloud seeding

Cloud brightening

Question 6

Describe some issues of Carbon Capture and Storage(CCS).

Answer 6

Only applicable to large sources & storage effectiveness is questionable - may be inefficient

Question 7

Describe the process of ocean storage.

Answer 7

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

Question 8

Describe the process of geological storage.

Answer 8

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

Question 9

Describe the climate effects of aerosols.

Answer 9

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

Question 10

How did Mount Pinatubo demostrate the climatic effects of aerosols?

Answer 10

The volcanic aerosols in the stratosphere excites the positive phase of the NAO - differential heating between low and high latitudes in stratosphere, strenghtening 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

Question 11

Contrast CDR and SRM.

Answer 11

SRM cheaper & fast to implement although it does not address ocean acidification and affects both the hydrological cycle & atmospheric circulation