As the Ukrainian crisis deepens, international observers have become more and more concerned about a direct military clash between the US and Russia. Once an armed rivalry erupts, it is likely to extend to the globe. And it is not impossible that a world war could break out.

The world war is a form of war that the whole world should face up to. During human evolution, the world war has entered its third development phase.

The first phase took place between nomadic societies and farming groups. The second phase was featured by colonial wars, with WWI and WWII as its special representatives.

Currently, the world has entered an era of new forms of global war.

Outer space, the Internet and the sea have become the battlefields of rivalry. Technology is the key, and the number of countries involved is unprecedented.

The rivalry on the outer space and the Internet takes place with the rivalry on the sea as the center stage. During WWII, some major powers attached significant importance to the sea.

Alfred Thayer Mahan, a US military strategist who died in 1914, coined the notion of sea power. He advocated valuing the naval forces, commercial fleet and overseas military base, which served for wars on the land.

But nowadays, we stress the importance of power in the sea. Judging from the contention of the global sea space, the Arctic Ocean, the Pacific and the Indian Ocean have seen the fiercest rivalry. It's likely that there will be a third world war to fight for sea rights.

In an era when a third world war may take place, an important topic for the Chinese military is how to develop its power to maintain its national interests.

This should become the basis for its development, because since the founding of the PRC, the development of its military forces has been centered around maintaining its rights on the land. As the rivalry on the sea grows intense, China's military development should shift from maintaining the country's rights on the land to maintaining its rights on the sea.

Meanwhile, China is standing at the focal point of rivalries. This requires China to develop its military power based on a global war. China is in the heartland of the Arctic Ocean, the Pacific Ocean and the Indian Ocean.

The development of China's sea power touches the nerves of many countries. China needs to develop its military power to avoid being squeezed to a passive position.

China's overseas interests have spread all over the world. As the US has been shifting its attention to the Asia-Pacific region, especially aiming at China, China's overseas interests have been increasingly threatened by the US.

Without large-scale military power, securing China's overseas interests seems like an empty slogan.

The long-range or overseas combat capabilities of China's sea and air forces are quite limited yet. If we don't view the development of sea and air forces with a farsighted view, we will face various restraints when building up the combat capabilities of sea and air forces or maintaining overseas interests. This will lead to the backwardness of China's sea and air forces.

China should not be pushed into a passive position where it is vulnerable to attacks. We must bear a third world war in mind when developing military forces, especially the sea and air forces.

The author is a professor at the PLA National Defense University.