In an effort to help save the environment, U.S. singer Sheryl Crow is calling on everyone to limit the amount of toilet paper used "in any one sitting" to one square.

Crow made the suggestion in her blog chronicling her recent tour of the United States on a biodiesel-powered bus to raise awareness about climate change.

She and environmental activist Laurie David toured 11 university campuses to persuade students to act to help safeguard the world's environment. 

"I have spent the better part of this tour trying to come up with easy ways for us all to become a part of the solution to global warming. Although my ideas are in the earliest stages of development, they are, in my mind, worth investigating," she writes.

"One of my favorites is in the area of conserving trees, which we heavily rely on for oxygen.

"I propose a limitation be put on how many squares of toilet paper can be used in any one sitting.… We can make it work with only one square per restroom visit."

Crow acknowledges there could be occasions when the one-square limit might not suffice, such as "on those pesky occasions where two to three could be required."

She writes that when she presented the idea to her younger brother, he went a step further, suggesting that people could "just wash the one square out."

Crow's other green ideas include a clothing line she has designed with a detachable "dining sleeve" that can be used as a napkin, thereby saving on the use of paper napkins.

She also suggests a reality show in which participants compete to live the greenest life.