Each of the following describes
an existing problem with a known solution. But the engineering and construction
communities remain largely oblivious -- of the problem, of the solutions, or
of their role in both...

The production of portland cement -- the glue that holds concrete together -- accounts
for seven to eight percent of the total greenhouse gases produced on Earth
by human activity. However, it is now well-established that the residue from
coal-fired power plants, or fly ash,
can be used to replace half or more of the cement in concrete, at lower
cost and higher quality.

Straw left in the fields after the harvest of rice, wheat and other grain
crops has historically been burned at great cost to air quality. However,
it is now well known that baled
straw can be stacked and plastered to create surprisingly strong, durable
and superinsulated buildings.

Large scale animal farms generate huge quantities of waste that pollute local
ecosystems and watersheds. However, that waste can be diverted into constructed
wetland areas in which beautiful groves of timber-quality bamboo
grow year-round, yielding an annual harvest of a versatile building material.

Rice is the primary food crop for most of the world's population. Worldwide
we burn 60 million tons a year of just hulls (the papery covers that are removed
from the grain in milling), thereby generating extensive air pollution. However,
pilot projects burn rice hulls in cogeneration plants to produce electricity,
and the ash collected from the exhaust
has been shown to be a performance-enhancing additive/replacement for cement.
Rice producers worldwide can turn their waste into power and building materials!