The topic is going to be plastic pollution in particular about plastic straw pollution. Wheat straw product is a great plastic alternative. The position would be to encourage large firms and companies to use wheat straw product as plastic alternative.
For the essay, make sure to form an argument/position/opinion on an environmental issue and then defend your argument/position/opinion using 1) the research you have done on the topic and 2) what you have learned about environmental economics from the lectures.