Water And Carbon: Carbon Sequestration Flashcards
(22 cards)
What is reforestation (N)?
The replanting of trees to trap CO2. Trees need to grow for a long time to be an effective form of Carbon Sequestration
What is mixing ocean layers (N)?
Large vertical pipes pump nutrient-rich water to the surface triggering algal blooms which would trap carbon
What is bioenergy with CCS (BECCS) (H)?
Like CCS but biomass is burned specifically to then be captured and stored underground
What is acid neutralisation (H)?
As carbon dioxide mixes into the oceans, they will gradually become more acidic. This means they can absorb less carbon dioxide as species such as phytoplankton will cease to exist. Adding limestone to the oceans could neutralise the sea water and increase absorption again
What is peat bog restoration (N)?
They hold dead plant and mosses which stores masses of carbon
What is carbon capture and storage (CCS) (H)?
Extracts carbon from the atmosphere or waste pipes of power plants. The waste carbon is pumped underground into an unused space
What is biochar (H)?
Charcoal is made and then added to the soil to increase its fertility and agricultural productivity, as well as trapping carbon into the soil
What are subterranean injections (H)?
Carbon dioxide can be injected into depleted oil and gas reserves or into the ocean
What is deep basalt storage (H)?
Mixing carbon dioxide with basalt deep in the oceans would create carbonate and hydrate minerals which are more dense and would settle on the sea bed
What is Iron and Urea fertilisation (N)?
Iron: The deposition of iron-rich dust into the oceans, this encourages phytoplankton growth which removes carbon from the atmosphere.
Urea: Fertilising the oceans with urea (a nitrogen-rich substance) could also encourage plankton growth - this has been planned off the west coast of Australia
How is agriculture used as a method of carbon sequestration (N)?
Reduce the use of machinery and chemical fertilisers, plant grasses and weeds between crop planting seasons, avoid overgrazing, cover bare paddocks with hay or dead vegetation, allow degraded land to recover
What is wetland restoration (N)?
Wetlands are areas of land saturated with water, e.g swamps, marshes, mangroves. 14.5% of the world’s soil carbon is found in wetland areas. Only 6% of the world’s land is composed of wetlands
What is carbon sequestration?
The process of capture and long-term storage of atmospheric CO2. This mitigates (slows) or stops global warming and reduces climate change caused by burning fossil fuels and forests
What is terrestrial carbon sequestration?
- The process through which CO2 from the atmosphere is absorbed naturally through photosynthesis & stored as carbon in biomass & soils.
- Tropical deforestation is responsible for 20% of world’s annual CO2 emissions, though offset by uptake of atmospheric C02 by forests and agriculture
How can greenhouse gas emissions be reduced via terrestrial carbon sequestration?
- Avoiding emissions by maintaining existing carbon storage in trees and soils
- Increasing carbon storage by tree planting or conversion from conventional to conservation tillage practices on agricultural lands
What are the limitations of terrestrial carbon capture?
- Carbon seq. rates differ based on the species of tree, type of soil, regional climate, topography & management practice
- Pine plantations in SE United States can accumulate almost 100 metric tons of carbon per acre after 90 years - Carbon accumulation eventually reaches saturation point where additional sequestration is no longer possible (when trees reach maturity, or when the organic matter in soils builds back up to original levels before losses occurred)
- After saturation, the trees or agricultural practices still need to be sustained to maintain the accumulated carbon and prevent subsequent losses of carbon back to the atmosphere
What is geological carbon sequestration?
Storing of CO2 underground in rock formations able to retain large amounts of CO2 over a long time period
- Held in small pore spaces (have held oil and nat. gas for millions of years)
What is the Midwest Geological Sequestration Consortium (Illinois Basin)?
- 1/7 regional partnerships selected to determine the best approaches for capturing and storing CO2 that might otherwise contribute to global climate change
- Assess geological carbon sequestration options in the 60,000 square mile Illinois Basin (Within the Basin are deep, noneconomic coal resources, numerous mature oil fields and deep saline rock formations with potential to store (O2)
- Feb 2009: Successfully completed 8,000 ft deep injection well
- By 2013, a total of one million metric tons of carbon dioxide (roughly the annual emissions of 220,000 automobiles) is expected to be stored within the formation.
What is the underlying theory of the Hellisheidi geothermal power station in Iceland?
Carbonated water is injected into the rock and hopefully reacts with the Ca and Mg present. This is called enhanced weathering calcium and magnesium are present in basalt - but rarely as simple oxides where the equations would be simple:
- CaO + CO2 → CaCO3
- Mgo + CO2 → MgCO3
- However silicate minerals of these elements are common in basalt, so an example reaction might be:
- Mg2SiO4 + 2C02 → 2MgCO3 + SiO2
As a result CO2 is locked away with no dangerous byproducts.
What are the possible problems with the Hellisheidi geothermal power station?
- These reactions are exothermic and reversible if the rock is later heated.
- The nearby Hengill volcano, generated a swarm of low magnitude earthquakes as a result of pumping water without the CO2 with 250 quakes being reported on 13 September 2011. There have been earthquakes reported there due to the water pumping previously.
Proceedings at the 2010 World Geothermal Congress reported that reinjection at Hellisheidi had induced seismic activity.
What is ocean carbon sequestration?
Carbon sequestration by direct injection into the deep ocean involves the capture, separation, transport, and injection of C02 from land or tankers
- 1/3 of CO2 emitted a year already enters the ocean
- Ocean has 50 times more carbon than the atmosphere
Carbon is naturally stored in the ocean via two pumps, carbonate and biological, and there are analogous man-made methods, direct injection and ocean fertilization, respectively. Eventually equilibrium between the ocean and the atmosphere will be reached with or without human intervention and 80% of the carbon will remain in the ocean. The same equilibrium will be reached whether the carbon is injected into the atmosphere or the ocean. The rational behind ocean sequestration is simply to speed up the natural process
What are the limitations of carbon capture?
Carbon Sequestration is not yet viable at a commercial level
• Small scale projects demonstrated (lab experiments) but CS is still a developing technology
• Concern with injecting carbon dioxide into ground or ocean because fear of leaks into water table or escape of CO2 into a massive bubble that can potentially suffocate humans and animals
