3. Vortices and global warming
3.1. Vortices caused by human activity
Recently, humans have created a novel means of forming large-scale vortices capable of affecting atmospheric circulation. This technology is jet-powered flight. Twin-engine aircraft, such as commercial passenger jets, create vortices as they fly. Wake turbulence is atmospheric disturbance that is formed by the passage of an aircraft through fluid (Figures \ref{170188} and \ref{803149}); it has several components, of which the most noteworthy are vortices formed by wingtips and by jetwash  \cite{2e2}18. These vortices are sometimes made visible by contrails, and can persist for long periods of time if undisturbed.