NASA's prediction that the sun's next 11-year activity phase or "Cycle 25: will be one of the weakest in centuries and is likely to decrease until 2100, has led some scientists to foresee a "mini ice age" in the future.

Experts at NASA and the University of Arizona analyzed data derived from magnetic-field measurements 120,000 miles beneath the sun's surface and concluded that Cycle 25, whose peak is due in 2022, will be a great deal weaker still.

According to climate scientists, after emitting unusually high levels of energy throughout the 20th Century, the sun is now heading towards a "grand minimum" in its output, threatening cold summers, bitter winters and a shortening of the season available for growing food.

Data issued recently by the Met Office and the University of East Anglia Climatic Research Unit confirmed that the rising trend in world temperatures ended in 1997.

The MET data showed that average global temperature in 2011 was the same average as in 1997 at 0.36 C, unlike in the previous decade when temperatures was steady at around 0.44 C degrees above average.

"If solar output reduced below that seen [in the late 1600s] the global temperature reduction would be 0.13 C," the U.K. Met Office said. While this is not a big change, the coming lull in the sun's activity may mean a decrease in world temperatures, scientists said.

"The figures suggest that we could even be heading for a mini ice age to rival the 70-year temperature drop that saw frost fairs held on the Thames in the 17th Century," a Daily Mail article said.

However, as to the impact of global warming of the sun's diminishing activity, the Met Office said that the consequences could be negligible because the impact of the sun on climate is far less than man-made carbon dioxide.

"Our findings suggest a reduction of solar activity to levels not seen in hundreds of years would be insufficient to offset the dominant influence of greenhouse gases," said Peter Stott, one of the authors.