That Jara depends on how many they build vs how long the Europeans retain there total carrier force for. The first European carrier to hit retirement is likely the Italian carrier Garibaldi, she was commissioned in 1981. If the Italian navy builds a replacement, then I figure a tie. As I don't see the PLA needing more them 5 carriers max. however the Italians or another European navy Like the French Navy commissioning a second carrier or maybe the Germans opening a carrier program have to replace Garibaldi with a new carrier If they dont then China might take the two spot, but again there is a If. That if is if they invest in five carriers. The question for the PRC is one of time. The PRC is in a race against time. Most projections of the population show China on a downward spiral of population in the next thirty years. With somewhere around fourty years from now the population of the PRC being roughly equivalent to the current American population. That's a major shift and historically its almost impossible to maintain the same level of economic growth and development with a major population decline. This would effect the entire political and military standing of China, and causes any predictions about a future Chinese dominant geopolitical shift to be questioned. So the If's. If China can keep her standing, If Europe can keep her carriers.
personally I think they will end up with a tie. With Russia eventually taking number three on carriers.