Answer: Since I do not have access to the lesson, and I can't see which other issues or environmental challenges you have discussed (I imagine waste and deforestation, for instance), I will select pollution. As a government leader, I would focus on pollution, specifically on air pollution.
Explanation: In order to solve this issue, I would encourage the use of electric or plug-in hybrid electric vehicles by providing significant economic incentives to both the industry and the consumers. In addition, I would progressively discourage (and eventually perhaps forbid) the sale of traditional incandescent light bulbs, which should be replaced by efficient light bulbs and appliances. Finally, cars and other vehicles would be required to pass inspections twice a year, in order to guarantee that they are using fuel efficiently.