Which of the following is a method used in geoengineering?

Solar Radiation Management (SRM) is a method used in geoengineering that focuses on reflecting sunlight away from the Earth to mitigate the effects of climate change. It involves techniques designed to alter the Earth's radiative balance by increasing the reflectivity of the atmosphere or surface. This can include ideas such as injecting aerosols into the stratosphere, cloud seeding to enhance cloud reflectivity, or deploying space-based reflectors. The goal of SRM is to manage global temperatures by reducing the amount of solar energy that reaches the surface.

The other options provided, while they relate to climate or environmental management, do not fall under the category of geoengineering as defined by practices specifically aimed at deliberately manipulating the Earth's climate systems on a large scale. Afforestation, for instance, increases carbon sequestration through tree planting but operates on a natural, biological level rather than through geoengineering techniques. Wind energy conversion relates to harnessing wind for electricity generation and does not involve direct intervention in the climate system. Conventional agriculture focuses on food production methods without aiming to directly alter global climate dynamics.