Facebook tools are an efficient way to drive cause-based promotions, too.

FORBES: 7 Facebook Tools You Can Use To Build A Movement

So the decline of these carbon-efficient ecosystems is a valid cause of concern.

UNESCO: World Water Assessment Programme (WWAP)

This would be a disaster for the AARP, but a boon to the cause of making Medicare more efficient (and thus more sustainable).

FORBES: Move up http://i.forbesimg.com t Move down

Shipping will probably gain market share from less efficient modes of transport, but higher fuel prices may also cause the entire transportation pie to shrink.

FORBES: A Leader in Efficient Shipping

Current tax policies, including the estate tax, cause wealthy people to put their money in tax havens and other tax-efficient savings vehicles or gift it to family members, trusts and charities.

FORBES: 10 Reasons Reagan Could Cut The Top Tax Rate To 28%, But Romney Can't

This change in the structure of taxation would cause those now covered by employer plans to choose less generous packages and therefore make more efficient choices about health care.

CNN: Commentary: US health costs out of control

Studies show that Mercosur's high external tariffs cause Argentina, Brazil, Paraguay and Uruguay to import from one another even when it would be more efficient to buy goods elsewhere.

ECONOMIST: Do regional trade agreements encourage free trade?