A lot of damage is being done to the ice in the Arctic and particularly, the enormous ice cap that is Greenland.
Researchers found the ice sheet is very vulnerable even in winter. Rain has caused the ice sheet to melt; in years past it would have fallen as snow. But no longer, there are new findings that need to be calculated into climate change projections.
David Shukman writes for the BBC Global.
The lead author of the study, Dr Marilena Oltmanns of the GEOMAR ocean research centre in Germany, told BBC News: "We were surprised that there was rain in the winter.
"It does make sense because we're seeing flows of warm air coming up from the South, but it's still surprising to see that associated with rainfall."
Another scientist on the study, Prof Marco Tedesco of Columbia University in New York, said that the increase in rain had important implications.
Even if it falls during winter, and then quickly refreezes, the rain changes the characteristics of the surface, leaving it smoother and darker, and "pre-conditioned" to melt more rapidly when summer arrives.
The darker the ice is, the more heat it absorbs from the Sun - causing it to melt more quickly.
"This opens a door to a world that is extremely important to explore," Prof Tedesco said.
"The potential impact of changes taking place in the winter and spring on what happens in summer needs to be understood."
A smoother surface, particularly a "lens" of ice, will allow meltwater to flow over it much faster and being darker means that more of the Sun's rays are absorbed, further speeding-up the warming process.
Pictures taken by a British research team, caught in a rainstorm on the ice-sheet last year, show how a bright highly reflective landscape of snow and ice was turned into a much darker scene.
Shukman also interviewed Jason Box who was not part of this particular study. He has experienced the rainfall in Greenland first hand and convinced that rain on the ice sheet is as damaging as a summer melting on top of the surface. He found that after it rained the surface ice got darker. A darker surface area absorbs more sunlight as the light is not reflected is back to space.
(Jason Box does not hold back in this video on geoengineering. I provide a FB link as strong language is used).
Prof Jason Box, a glaciologist not involved in the new study, says the research builds on earlier work by him and colleagues published in 2015 that found that summer rainfall could increase the rate of melting.
Their analysis found that because water has a high heat content, it takes only 14mm of rain to melt 15cm of snow, even if that snow is at a temperature of minus 15C.
"There's a simple threshold, the melting point, and when the temperature goes above that you get rain instead of snow," he said.
"So, in a warming climate it's not rocket science that you're going to have more rain than snow, and it's one more reason why the ice sheet can go into deficit instead of being in surplus."
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