Our life depends on ocean in many significant ways. The ocean and the seafloor provide huge resources for us including food, minerals, and energy.
Ocean life provides a vital ecological balance.
More than just providing resources, the major importance of ocean is that it strongly influences weather and is a very critical part of the global climate system. You must be knowing about El Nino. El Ni o is a disruption of the ocean-atmosphere system in the tropical Pacific having important consequences for weather around the globe. The consequences might be dreaded like change in tropical rainfall, which affect wind patterns over much of the globe. This may lead to famine, drought, heavy rainfall in non-monsoon period, late setting of winter, and so on.