I thought this was interesting enough for a posting...for the other two people that are actually interested in this stuff (or not).
Have you noticed on cold wintery days (if you are in one of those locations which has those) where you notice it feels warmer when you have cloud cover than not? At least in general?
This should raise some questions in that regards towards rising temperatures in other areas.
I'm not going into all the scientific details (for which, if those who don't like my thoughts on Climate Change nor the participation I may have in it at times will crucify me for in all likihood if they choose to comment at all), but this idea hit off on some searching for reasons why the meltoff of the Greenland Ice sheet was faster than expected in many ways.
So, they started looking at cloud cover and how it may be affecting the melt off. There is more research to be done, but right now the results look like they may have a major factor in regards to how this may be occurring.
In short, or kind of trying to say it in brief, indications are that cloud cover has caused some of the temperatures to be higher which obviously affects the snowpack and ice sheet. (specifically with major thoughts in the regards of refreezing, reducing it from a matter of 58% to 45%).
Could be interesting to see the follow-ups to this.
Oh...and lest I forget since people ALWAYS want some sort of link...
Here's is a link to at least one report of the study...IF you like to read this type of stuff...
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It says cloud cover increases runoff due to reducing refreezing, not that it increases melt or raises temperature.
Actually, you have to take the effect chain a bit further...
Clouds are made of water
Water absorbs infrared radiation
This slows the rate at which heat escapes to space
Ergo, clouds act as a greenhouse warming agent
This warming reduces refreezing
Which then increases runoff
So it really is because the clouds cause warming. The same way that CO2 and other greenhouse gases do. The primary difference being that most greenhouse gases are very low mass and thus quickly become fairly evenly mixed throughout the atmosphere... while cloud cover (and atmospheric water in general) varies greatly by location at any given time.
That said, research has also recently shown that warmer temperatures are leading to a 'solid ice layer' at the top of the Greenland ice sheet. Rain then runs off this layer rather than sinking in to the more porous 'compressed snow' beneath it. Thus, there are a number of factors contributing to increased runoff / decreased mass gain for the ice sheet.
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Yes, but none of that changes that the paper doesn't say what GwL is saying it does.
Perhaps you should have read what I stated in my post...which directly states what you restated already about the refreezing.
Of course, perhaps reading beyond the title of the thread isn't something you do regularly?
In light of my post, I'm actually rather puzzled by your post regarding what I actually wrote...
In addition, it states directly in the paper regarding WHY the refreezing is reduced...which actually DOES increase the ice melt seasonally in regards to the volume of the snowpack and ice shelf.
As I said, this is still ongoing research, but pretty fascinating thus far...but the idea is that this is directly related to the temperature and the cloud cover, and that this perhaps has some major impact (which does not mean it is the source of all of it, but could be an enhancement or major factor...as I already said, research is ongoing).
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Ok, the difference you two are talking about here is subtle, but valid.
Basically, GWL's wording suggests that clouds "increase the ice melt"... which isn't what the study is talking about. Rather, they say that increased cloud cover is 'decreasing ice formation' by allowing more rain to run off without ever freezing. End result either way is 'less ice'... it's just a difference in how we get there.
There has been a lot of debate about Greenland ice loss because the estimates of observed melt and calving haven't always been as high as the estimates of observed mass loss. What this study and others suggesting increased runoff are suggesting is that the difference is because we have been over-estimating ice formation. As the planet has warmed and Greenland has seen more cloud cover and rain it has been trending more towards rain running off rather than freezing and adding to the ice mass as had been assumed.
PS: Hmmm, actually reading the study now... they are mostly looking at meltwater runoff rather than precipitation runoff. That comes down to an increase in ice melt (because more runs off rather than re-freezing in place).
Also, Greenland's got some greenhouse effect. Sunlight can become trapped under really high clouds. That combined with all the other factors mentioned may be making Greenland actually green.