Fill in the blanks to make the following statements correct.
a. The emission of greenhouse is a good example of an ______ externality. Firms and individuals have not internalized the ______.
b. Geographically, the externalities associated with greenhouse gas emissions are an ______ problem, which was the motivation behind the of 1997.
c. It is estimated that, in order to stabilize Earth's climate, the annual flow of global GHG emissions must fall by approximately______ percent from its current level.
d. Canada's emissions of greenhouse gases increased by roughly ______ percent between 1990 and 2009.
e. Most economists believe that it is necessary to impose an ______ on GHG emissions, which would force polluten to ______ the externality. Two market-based policy options to achieve this outcome are an ______ and an ______ system.