escalate
/ˈeskəleɪt; `ɛskəˌlet/ v[I, Tn]
(cause sth to) increase or develop by successive stages; become or make (sth) more intense （使某事物）逐步增长或发展; （使某事物）更紧张
the steadily escalating level of unemployment 失业率日益上升
House prices have escalated rapidly. 房价已急速上涨.
The Government is deliberately escalating the war for political reasons. 政府出於政治目的蓄意使战争逐步升级.