Question map
Consider the following activities : 1. Spreading finely ground basalt rock on farmlands extensively 2. Increasing the alkalinity of oceans by adding lime 3. Capturing carbon dioxide released by various industries and pumping it into abandoned subterranean mines in the form of carbonated waters How many of the above activities are often considered and discussed for carbon capture and sequestration?
Explanation
The correct answer is Option 3 (All three) because each activity represents a scientifically recognized method for carbon capture and sequestration (CCS) or carbon dioxide removal (CDR).
- Activity 1 (Enhanced Weathering): Spreading ground basalt on soil accelerates natural chemical weathering. Basalt reacts with atmospheric CO2 to form stable carbonates, effectively locking carbon in the soil and oceans for millennia.
- Activity 2 (Ocean Alkalinity Enhancement): Adding alkaline substances like lime (calcium oxide) to oceans neutralizes acidity and enhances the water's capacity to absorb CO2 from the atmosphere through chemical equilibrium.
- Activity 3 (Geological Sequestration): Pumping carbonated water (CO2 dissolved in water) into subterranean sites, such as basaltic formations or abandoned mines, facilitates "mineral carbonation." Projects like Iceland's Carbfix demonstrate that CO2 injected this way reacts with host rocks to turn into solid minerals.
Since all three techniques are actively discussed in climate mitigation strategies to reduce atmospheric greenhouse gas concentrations, Option 3 is the most comprehensive and accurate choice.
PROVENANCE & STUDY PATTERN
Guest previewThis question tests 'Frontier Climate Tech'—specifically Geoengineering and Carbon Dioxide Removal (CDR). It punishes reliance on static textbooks (which only cover basic afforestation/CCS) and rewards aspirants who track 'Climate Solutions' in science news (DownToEarth, The Hindu S&T, IPCC reports).
This question can be broken into the following sub-statements. Tap a statement sentence to jump into its detailed analysis.
- Statement 1: Is spreading finely ground basalt rock on farmland (enhanced weathering) commonly discussed as a carbon capture and sequestration method?
- Statement 2: Is increasing ocean alkalinity by adding lime (ocean liming / alkalinity enhancement) commonly discussed as a carbon capture and sequestration method?
- Statement 3: Is capturing carbon dioxide from industries and pumping it into abandoned subterranean mines in the form of carbonated water commonly discussed as a carbon capture and sequestration method?
- Explicitly uses the term “enhanced weathering” in the context of spreading finely ground minerals to increase CO2 sequestration.
- Describes the specific action of “spreading finely ground alkaline substances” as a method for increasing ocean CO2 uptake, showing enhanced-weathering concepts are discussed as carbon removal.
- Describes marine enhanced rock weathering (mERW) where finely ground silicate minerals are spread in coastal zones to release alkalinity.
- Shows the enhanced-weathering approach (spreading ground silicates) is discussed as a means to enhance alkalinity and thus carbon sequestration — albeit in marine/coastal settings rather than farmland.
Describes chemical weathering processes driven by water, CO2 and acids that decompose rocks to finer material — establishing that weathering reactions involve atmospheric CO2.
A student could combine this with the basic fact that some silicate rocks react with CO2 when weathered to infer that deliberately increasing rock surface area (grinding basalt) might increase CO2 uptake.
Explains that chemical weathering (including carbonation) is accelerated by water, CO2 and biological acids, implying weathering can be enhanced by environmental contact.
One could extend this to ask whether spreading fine rock on soil increases contact with water/CO2 and therefore enhances CO2-consuming weathering reactions.
States that biogeochemical cycles include phases of weathering of rocks and that the carbon cycle is tied to weathering processes.
A student might link this to the idea that altering the weathering phase (more reactive rock exposed) could influence carbon flow from atmosphere into minerals or soils.
Defines artificial carbon sinks and lists carbon capture and storage proposals as an approach to store carbon for indefinite periods.
Use this to frame enhanced weathering as a candidate 'artificial sink' hypothesis to investigate in literature or policy discussions.
Notes carbon capture/ sequestration is an established category of mitigation and that artificial sinks (besides natural ones) are considered strategies.
This supports searching within carbon-capture topics for specific methods (e.g., enhanced weathering of rocks) as potential proposals under that umbrella.
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