When you’ll need to do things on a global scale such as a sea wall that would say protect the eastern coast of the US it would definitely fit into geoengineering.
By this definition a small scale carbon capture process that is borderline effective is considered climate engineering but managing 1000’s of km of dams and dikes isn’t.
I am just asking whether geoengineering has been demonstrated as a feasible solution to reverse trends of global warming and anthropogenic greenhouse gas emissions.
Geoengineering proposals typically aim to reduce the global greenhouse effect through several hypothetical means (like increasing cloud albedo.)
Dykes and dams that curtail flooding of coastal regions can be monumental undertakings but aren't typically referred to as "geoengineering." Hydropower from a dam could be a good way to reduce carbon emissions, but again wouldn't be considered geoengineering.
By this definition a small scale carbon capture process that is borderline effective is considered climate engineering but managing 1000’s of km of dams and dikes isn’t.