Typhoon Haiyan may have created a carbon "burp" as it uprooted large swaths of Philippine forest, releasing carbon into the atmosphere, scientists say.

While it is too early to say how much carbon Typhoon Haiyan might have unlocked, calculations for previous tropical storms suggest the amounts could be significant.

A study of Hurricane Katrina found the 2005 storm released more than 100 tons of carbon by uprooting more than 300 million trees when it slammed into the United States -- more than half the amount of carbon absorbed annually by U.S. forests.

Because Haiyan was even stronger and the Philippines have a greater average forest cover than the eastern United States, the carbon release figure could well be higher.

But, paradoxically, tropical cyclones weaker than Haiyan could cause even more carbon release, researchers said; studies of Katrina's wreckage found that the greatest carbon loss occurred in the outer regions of the storm.

"Although the higher wind strengths caused more damage for a given area, the lower wind strengths covered a much larger area," Justin Fisk, a University of Maryland scientist who has done a follow-up study on Katrina, told NewScientist.com. "Because of this, a large, less intense storm can potentially do more damage than a small, more intense storm."

Although forests can recapture carbon as they grow back, it depends on the speed of re-growth and on how frequently any one region can expected to experience tropical storms, scientists said.