Worried about global warming? A more imminent threat may be worldwide fiscal crises.

Consider that Monday, Greece's prime minister announced spending cuts intended to rein in a growing governmental budget deficit.

"Greece faces the risk of sinking under its debt,'' the leader, George Papandreou, said.

Greece isn't alone. Ireland and Spain are dealing with budget deficits, too.

Moody's, the credit ratings agency, estimates total global debt in 2010 could reach more than $49 trillion, as measured in U.S. dollars. The members of the G-7 group of rich countries are to account for more than three-quarters of the increase.

Papandreou promised to reduce Greece's deficit spending, projected at 12.7 percent of that nation's economic output for 2009.

Now consider the U.S. budget deficit for 2009 was close to 13 percent of our gross domestic product. And that's just the portion of federal spending added to the existing debt load. Last fiscal year, the federal government spent about $3.5 trillion, nearly a quarter of the U.S. GDP.

Greece's PM pledged to bring that nation's annual deficit down to 3 percent of GDP by 2013, in line with the European Union's euro-zone requirement. President Barack Obama, when announcing the 2010 federal budget, announced similar goals for the U.S. in 2014.

Hitting those targets here would take billions more in taxes, spending cuts or both. But note those budgets still wouldn't be balanced. The national debt - now a record $12.1 trillion - would continue to grow.

That amount didn't accrue overnight. Spending has outpaced revenues for years. We cannot live beyond our means forever, however; at some point, that will have to reverse in order to pay down the debt.

Yet the new gang in Washington thinks we can borrow money in order to stimulate the economy. But most Americans - especially homeowners who used lines of credit based on home equity - have discovered we can't borrow and spend our way to prosperity.

The Peterson-Pew Commission on Budget Reform, a bipartisan group of former lawmakers and budget officials, Monday called on Congress and Obama to commit to dealing with the budget deficits and limit the national debt.

''Our slogan of 'Either we change or we sink' is more pertinent than ever,'' Greece's prime minister said Monday.

Unless the political culture changes in Washington, we foresee our nation sinking ever deeper into debt.