For the first time since WWII, no US aircraft carriers are deployed - but Russia's and China's are

The US operates 10 Nimitz-class flat top aircraft carriers, more than the rest of the world, but for the first time since the close of World War II, not a single carrier is deployed.

The US had the USS Dwight D. Eisenhower deployed in the Persian Gulf carrying out a fast-paced air campaign against ISIS in Iraq and Syria until late December, but that carrier returned home on December 30.

But the pause in activity, while highly unusual, won't last long. On Thursday, the USS Carl Vinson left its port in San Diego to head for the Western Pacific, where tensions with China have reached an uncomfortable high.

Meanwhile, the USS George H.W. Bush, which has been detained longer than expected, prepares to replace the Eisenhower in the fight against ISIS.

The lul in US carrier activity happens to coincide with a spike in carrier activity from the US's stiffest competition at sea - Russia and China.

While the US has no presence in the Mediterranean, Russia's sole carrier, the Admiral Kuznetsov, has been deployed off the coast of Syria for months. The Kuznetsov suffered major mechanical issues and some high profile plane crashes, but overall managed to achieve its first-ever combat deployment.

In the Pacific, the Chinese Liaoning, China's sole aircraft carrier, just carried out live-fire drills in the heavily contested South China Sea. The Liaoning rattled the Taiwanese as it skirted the island during it's deployment. China has been keen to demonstrate it's control over Taiwan since President-elect Trump broke with decades of US foreign policy tradition and accepted Taiwanese President Tsai Ing-Wen's phone call.

Experts have called for an increased US Navy presence in the South China Sea to deter the Chinese from establishing regional hegemony and to affirm international norms such as right of innocent passage.

Pentagon spokesman Peter Cook stressed that despite the lack of carrier deployments, the US has "a significant presence in both those areas and will continue to have a significant presence even though we may not at any one particular time have an aircraft carrier there."

The Navy, however, has repeatedly called for more carriers and combat ships to meet rising threats around the world.

While China's and Russia's Soviet-designed carriers pale in comparison to US carriers, their deployments have been meaningful in bolstering their perceived strength at a time when the US appears to be losing traction in international conflicts.