In the context of which of the following do some scientists suggest the use of cirrus cloud thinning technique and the injection of sulphate aerosol into stratosphere?

1. The question asks about the purpose behind two proposed geoengineering techniques: cirrus cloud thinning and the injection of sulphate aerosol into the stratosphere. 2. Cirrus cloud thinning aims to reduce the warming effect of high-altitude cirrus clouds, which trap outgoing infrared radiation. Thinning them would allow more heat to escape. 3. Sulphate aerosol injection into the stratosphere aims to mimic the cooling effect of large volcanic eruptions. These aerosols reflect incoming solar radiation back to space, reducing the amount of energy reaching the Earth's surface. 4. Both techniques are methods of Solar Radiation Management (SRM), a type of geoengineering proposed by some scientists as potential ways to counteract or reduce global warming. 5. Creating artificial rains involves different methods (cloud seeding). Reducing tropical cyclones or mitigating solar wind effects are not the primary stated goals of these specific techniques. 6. Therefore, the correct context is reducing global warming.