The United Nations Climate Change Conference 2022 has been scheduled to take place in November 2022, with a predominant emphasis on decreasing carbon emissions. Based on your understanding of the economic concept of 'externalities', answer the following questions:

a. Why there is such a big focus on reducing carbon emission

b. Explain how a carbon tax could assist in addressing the pollution issue. Support your answer with a graph (attach a photo of a properly labelled hand-drawn graph)

c. Should governments impose a Pigouvian tax (i.e., a tax on negative externality) until the pollution level reduces to zero? Why or why not?