An all out nuclear war between India and Pakistan will loft up to five million tons of black carbon soot into the atmosphere, and drop global temperatures by 1.4 degree Celsius, a Rutgers University study has said.

As part of their study, the researchers used a climate model shared by the Intergovernmental Panel on Climate Change to calculate the effects of exploding 100 Hiroshima-sized bombs over major cities.

The team found, besides polluting the atmosphere, the radiation would shorten growing seasons in the middle latitudes. In some cases, the growing seasons would fail entirely, they said.

"By explaining the consequences to the world, we hope nothing like this will ever happen," said Alan Robock of Rutgers University in New Brunswick, New Jersey, who conducted the study.

He said while the US and Russia [Images] had destroyed thousands of warheads following their treaty on disarmament, India, Pakistan and North Korea had swelled their stockpiles.

As such, the threat of a 'nuclear winter' that would lower global temperature for a decade, always remained, New Scientist quoted him as saying.

The findings appear in the journal Atmospheric Chemistry and Physics.