At least 34 countries have plans, worth a total of $2.25 trillion.
With consumer prices expected to fall further, economic recovery might be tougher to achieve.
The president called for tougher fuel-efficiency standards Monday and may let states regulate vehicle emissions of greenhouse gases.
Losses on mortgage debt, followed by recession woes such as corporate bankruptcies and rising defaults on credit cards, delivered a one-two punch.
Most banks have tightened lending, choking off needed credit for some US businesses.
Efforts outside the US tend to amount to 1.5 percent of GDP or less, one tally finds.
Even if it adds up to $8 trillion, the final cost will be lower as US sells the assets it's now buying.
Until then, employment, output, and housing prices will keep falling.
Angry investors blame US regulators for one of the investment world's biggest scandals.
Auto woes of the Big Three could hurt plants south of the border – and spur migration north.