How can I reduce the amount of carbon dioxide into air? [[HELP SCHOOL PROJECT!]]?

I have summer homework for an AP class I signed up for last year. I just need some ideas for how i can increase my town's water supply during a drought and promote crop growth. Also, I need to find a way to reduce the amount of carbon dioxide in the air. the project is posted below if u care to read it.

Carbon Dioxide: Friend or Foe?

A Web Quest for AP Environmental Science

Introduction

It is the year 2030 in the town of Cabrillo-Carbonville. Widespread droughts have plagued the farmers this year with the majority of their crops dying off. Also the town has had to insist on mandatory water conservation methods in order to save their slowly diminishing water supply. To compound to the problem, it has been discovered that local dry cleaners and production plants have been discharging their solvents into the nearby creeks. Scientists have attributed the drought and severe weather conditions to global climate change due to excessive carbon dioxide levels. The town leaders have decided that they need to hire a consulting firm to address their problem of too much carbon dioxide and too little water. Otherwise they are going to have to import a lot of food and water in order to support their town's needs. Several firms are vying for this billion dollar contract and a decision will be made at next week's town council meeting.

The Task

Your firm wants to come up with the best idea for the town. This idea should help the environment, lower carbon dioxide levels, promote growth of crops, and increase water supply. As impossible as the task sounds, your employer wants your group to include as many ideas as possible. Therefore split up different areas of research and then meet to brainstorm what your group wishes to propose.

• Your documents are due on or before August 25, 2009 at midnight.

• You will present your findings at the next town council meeting (First week of school). You may use power point, posters, brochures, etc. Whatever you think you need to sell your idea.

The Process

Brainstorm and research the various components of the project.

Pick what aspects of the project you will include in your final presentation.

Prepare your brochures, posters, or Power Points.