How is mud bricks environmentally friendly??

"• The earth for making the bricks can often be taken from the property itself, which eliminates the energy use and greenhouse emissions from transporting the bricks.

• Mud brick can have very low embodied energy: no energy is needed to make the bricks, except human labour and the sun's heat. (It takes a lot more energy to fire conventional bricks.)

• At the end of the building's life, mud bricks can simply be broken up and turned back into earth.

• Mud brick provides good thermal mass, which can be used for effective passive solar design to store heat during the day for slow release at night - good for climates with warm days and cooler nights.

Finishes
Mud brick walls can be finished to provide different effects. For a smooth finish, you can fill in the mortar level with the bricks, or render the wall by smoothing an additional layer of mud over the surface. Alternatively you can scrape out the mortar so the bricks stand out to emphasis the natural, organic look of mud bricks."

-http://www.homeimprovementpages.com.au/article/mud_bricks