Since China is such a large country and since it is trying to become a major regional power, there are many global issues that could have a direct impact on it. Let us examine three such issues.
The first is the issue of pollution and climate change. China is by far the world’s largest consumer of coal and the largest emitter of carbon dioxide. This means that any world efforts to slow the accumulation of greenhouse gases in the atmosphere will have a major impact on China. In addition, China suffers from very serious air and water pollution. This will have a great impact on the country because it will have to find a way to reduce that pollution if it is to keep its people healthy and happy.
A second global issue is the issue of human rights. As the world becomes more convinced of the importance of democracy and rights, China continues to look worse and worse in that regard. As the push to enforce human rights gets stronger, China will be forced to make choices about whether it wants to ease its authoritarian ways. It is possible that the Chinese people, seeing the spread of rights and democracy, will become restive and cause problems for their government.
Finally, there is the connected issue of nationalism and separatism. We see today in Ukraine and the Crimea (among other places) that there are national/ethnic groups that want to have a greater degree of self-determination. China is a large country with a few large minority groups that are somewhat persecuted by the Han majority. If more regions around the world split off from, or achieve significant autonomy from, their national governments, Chinese minorities might be emboldened to press for more autonomy of their own.
These are some of the global issues that face China in the years to come.
I'm not sure if the economy is a bad enough to constitute a global issue, but as the economy goes down, countries like America will begin importing less goods from places like China, which will in turn lower their economy. Also, global warming will make a huge impact on China, since they have such a high population. They release more greenhouse gasses and pollutants simply because they have more people.