The most important reason that global regulation is important is the fact that the world's economy is becoming so much more globalized. In today's world, the economies of the different countries interact to such a great extent that, for example, the debt crisis in Greece can have a huge impact on American stock markets. In this environment, there is a case for regulations that cover all countries.
Globalization brings about a need for global regulation. In today's world, products made in China are sold all over the world. It makes sense, then, for there to be regulations that would ensure that these products would be safe. It would also make sense for these regulations to be global so that consumers in all countries would be protected.
There is also a need for global regulation so as to protect competition. When one country, for example, refuses to adhere to laws protecting intellectual property, its businesses gain an advantage over those from other countries. In order to make the competition fair, there need to be regulations affecting all countries.
Because the world's economy is so globalized the actions of any one country affect many others. Therefore, there is a need for global regulation.