The world's top bond fund manager is predicting largely favorable global economic conditions for 2012, but warns of three looming threats.

The Pacific Investment Management Co. expects the U.S. economy to grow 1 to 2 percent, the European economy to contract 0.5 to 1.5 percent, the Chinese economy to expand 7 to 8 percent and the Brazilian, Russian, Indian and Mexican economies to advance 3.5 to 4.5 percent.

Threat No. 1: Mideast War

But a big shock in oil prices would render these forecasts useless, Saumil H. Parikh, a portfolio manager at Pimco, warned in a recent commentary.

If Israel were to attack Iran over the latter's nuclear program, oil could surge to $300 per barrel, George Friedman, chief intelligence officer of Stratfor, a global intelligence firm, told Barron's.

Nouriel Roubini of Roubini Global Economics, an economics research firm, believes oil could hit $200 per barrel if Iran becomes entangled in a protracted conflict.

Rhetoric from both Iran and Israel has become increasingly bellicose and threatening in the past few weeks. On Tuesday, an Israeli official told Reuters that skirmishes with Palestinians in Gaza in the last few days were in a sense a mini-drill for Iran.

The quietly rising tensions in the Middle East between Israel and Iran must be addressed by global leaders in a unified manner before long, wrote Parikh.

Threat No. 2: Uncertain U.S. Policies

In January 2013, U.S. government stimulus programs worth a whopping 3.5 percent of GDP are set to expire, which could deal a devastating blow to the country's economy if Washington -- perhaps under a new administration -- does not extend them.

Even if Washington ultimately gets its act together and strikes an extension deal, the risk remains that ... political theatrics and uncertainty regarding the outcome will hinder confidence and animal spirits as they did before the debt ceiling debate of 2011, wrote Parikh.

Furthermore, this year's elections will determine the shape of U.S. fiscal policy going into 2013 and beyond, he wrote.

Threat No. 3: The French Turn Against Europe

The first round of the French presidential elections take place next month, and the fear is that French politics could hobble  cooperation with the Germans to bail out weak euro zone members like Greece.

Far-right candidate Marine Le Pen, a staunch Euroskeptic, wants France to leave the euro zone and opposes French participation in bailouts. She currently places third in the polls behind center-right President Nicholas Sarkozy and pro-Europe Socialist Francois Hollande.

Over the weekend, Sarkozy turned up his rhetoric by threatening to close France's borders to its euro zone neighbors unless there is continent-wide progress on controlling immigration

Hollande, for his part, is already clashing with German Chancellor Angela Merkel by criticizing with the European fiscal pact that Merkel and Sarkozy negotiated. Hollande believes the pact puts too little emphasis on growth and too much on austerity.

We will be following developments there closely, with particular focus on their potential impact on the French policy stance, Franco-German collaboration and the outlook for Europe, wrote Parikh.