Researchers in a new study are suggesting a link between rising global temperatures and an increase in powerful storms.

The study in the journal, Science, says researchers have found a sharp increase in the number of so-called Category Four and Category Five tropical cyclones since 1970. It says the storms, which are fueled by warm temperatures, increased in number by 57 percent over the period.

Meteorologist Kerry Emanuel, of the Massachusetts Institute of Technology, said there is a "strong suggestion" of a link between the changing climate and intensifying tropical cyclones.

But he says the devastation brought on by Hurricane Katrina cannot be blamed yet on global warming, adding that the affected region was densely populated along a vulnerable coast.

Climate specialists in the article say more studies are needed over the next decades to draw firmer conclusions.