Answer
Recent decades have witnessed the intensification of climate changes and many other environmental issues around the world. I would say solving an environmental problem should be the responsibility of internal governments instead of global governing bodies.
One good reason to hold this view is that the national administration could freely enact the legislation to address many green issues within the country. They know how the problems are created; know their people better and the way to involve them in finding solutions. For example, Australian official authorities have applied Carbon tax on many industries for curbing the concentration of pollutant particles especially carbon dioxide and methane in the atmosphere.
Another point to consider is that sometime international organizations may not understand the local issues which may change the direction of future plans. Through effective rules, local government can cut the license of polluting industries, or stop the usage of environmentally damaging materials like plastic, encouraging eco-friendly utensils like paper bags, and so on. Furthermore, the national government could capitalize on the mainstream media to inform citizens about the negative consequences of environmental problems and subsequently raise the awareness of environment protection. They can even organize tree-planting campaigns for environmental rehabilitation of the nation.
With all this taken into account, I believe that each national government should be liable for solving green problems instead of a multinational government due to some benefits of freely enacting laws and using media to raise citizens’ environment protection awareness.