Rapidly melting Arctic Ice Sheet and Hurricanes

[StormWarning1]

Is there a connection. check this link.

http://nsidc.org/news/press/20050928_hu ... tions.html

Also, the NSIDC is a great place to visit.

[Tampa Bay Hurricane]

Very interesting read...thanks

[chadtm80]

[krysof]

[StormWarning1]

another article from time.com

http://www.time.com/time/archive/previe ... 37,00.html

[aerojad]

Is there a connection.

Highly doubt it. If anything, introducing very cold water into a warm ocean body would cause less in the way of cyclone development - mainly confined to the northern reaches of the tropical Atlantic and right off the coast of Africa - the only places in the tropical Atlantic that cold currents get to.

[Terrell]

I would think that if the polar melting continues (depending on the overall severity of the melting) rising sea levels may be of concern to coastal low lying areas. As to hurricanes, I'd think it would depend on how much the ice lowers the ocean's temperatures and how long it takes for Sol to reheat them.

[Derek Ortt]

a melting ice sheet would likely reduce the number of canes as it means more cold water. It also could lead to an ice age

[PurdueWx80]

Ice melting produces cold, fresh water - both of which are more dense than surrounding sea water. This new water that has been locked up in ice for so long sinks (since it's denser) and has very little effect on tropical sea surface temperatures. Granted, ocean circulations/currents are much less simple than this - but the melting ice caps would almost certainly NOT affect tropical cyclone strength.

[aerojad]

I would think that if the polar melting continues (depending on the overall severity of the melting) rising sea levels may be of concern to coastal low lying areas. As to hurricanes, I'd think it would depend on how much the ice lowers the ocean's temperatures and how long it takes for Sol to reheat them.

Water won't rise if the North Pole cap goes away. The displacement of the ice is already in the water, thusly when the ice melts... it's already in the water.

Water won't rise unless the Greenland or Antartic cap were to go.

[Terrell]

I would think that if the polar melting continues (depending on the overall severity of the melting) rising sea levels may be of concern to coastal low lying areas. As to hurricanes, I'd think it would depend on how much the ice lowers the ocean's temperatures and how long it takes for Sol to reheat them.

Water won't rise if the North Pole cap goes away. The displacement of the ice is already in the water, thusly when the ice melts... it's already in the water.

Water won't rise unless the Greenland or Antartic cap were to go.

Is this melting of polar ice limited to the Northern Ice Cap, or is it also occuring in the South Pole and other places too?

[x-y-no]

:blow:

Was there something in particular in that question/answer session which prompted this reaction?

I thought it was quite balanced, myself.

[x-y-no]

Ice melting produces cold, fresh water - both of which are more dense than surrounding sea water. This new water that has been locked up in ice for so long sinks (since it's denser) and has very little effect on tropical sea surface temperatures. Granted, ocean circulations/currents are much less simple than this - but the melting ice caps would almost certainly NOT affect tropical cyclone strength.

Umm .. no. Fresh water from ice melt is less dense than salt water. Absent turbulent mixing, it would simply float in a layer above the salt water. Of course, such mixing does take place. Nevertheless, there is good evidence of a general freshening of the near-surface layer of the Arctic Ocean (with some regional variation, particularly with regards to the "great salinity anomaly" of the '60s and '70s, and some increased salinity in portions of the North Atlantic since '95).

[x-y-no]

I would think that if the polar melting continues (depending on the overall severity of the melting) rising sea levels may be of concern to coastal low lying areas. As to hurricanes, I'd think it would depend on how much the ice lowers the ocean's temperatures and how long it takes for Sol to reheat them.

Water won't rise if the North Pole cap goes away. The displacement of the ice is already in the water, thusly when the ice melts... it's already in the water.

Water won't rise unless the Greenland or Antartic cap were to go.

Is this melting of polar ice limited to the Northern Ice Cap, or is it also occuring in the South Pole and other places too?

While there has been a general retreat of the glacier/ocean interface along much of the Antarctic coast, this appears to be mostly balanced by increased inland precipitation.

The most pronouced melting trend is in the northern hemisphere (as, in fact, general circulation models have predicted would be the case with global warming).

[calculatedrisk]

a melting ice sheet would likely reduce the number of canes as it means more cold water. It also could lead to an ice age

Sorry, it doesn't work that way. If it was a closed system, the melting ice would cool the oceans. But it is an open system (more heat is coming into the system than going out), and the melting ice and the warm SST are a result.

[x-y-no]

a melting ice sheet would likely reduce the number of canes as it means more cold water. It also could lead to an ice age

I'd be interested in your justification for this opinion. Reduced ice cover would result in warming of surface waters due to lower albedo. But this is unlikely to influence tropical cyclogenesis anyway, since there is little surface transport from the arctic to the tropics.

[cjrciadt]

Would this example sum it up?:
Put one cube of ice in a glass of water(room temp.)
In the short term the water will cool down, but once the ice melts the water level will rise at the water temp will return to room temp or even higher than before.

[clueless newbie]

Ice melting produces cold, fresh water - both of which are more dense than surrounding sea water. This new water that has been locked up in ice for so long sinks (since it's denser) and has very little effect on tropical sea surface temperatures. Granted, ocean circulations/currents are much less simple than this - but the melting ice caps would almost certainly NOT affect tropical cyclone strength.

Cold water is denser, but fresh water is less dense. Introduction of this fresh water can disturb thermohaline circulation in north atlantic: warm salty tropical waters come with the gulf stream, get cooled up north and sink, 'sucking' in more warm water. Once the salty formerly warm water gets diluted with fresh water, the sinking tendency is not that strong and the gulf stream might actually get switched off. Don't ask me what would that mean - probably nothing good: much colder up north, but the warm water would stay down south. More thermal gradient = more severe weather

Alternatively, the gulf stream is not switched off and the artic keeps warming, due to positive feedback: onec ice has melted, the water up there will be warmed by the sun, alse methane will be released from permafrost.

How would that influence tropical development nobody knows - the waters down south will be warmer, the question is what would be temperatures in the upper troposphere (that's the radiator of a hurricane - it is a heat engine after all). Perhaps more importantly what would be the prevailing environment - shear, SAL, generation of cape verde waves etc.

Saying that changes up north would almost certainly NOT affect tropical development is wishful thinking and/or ignorance, at best. The effects will be there and easily might be quite strong (atmosphere and oceans are complex dynamical systems with chaotic tendencies - study a bit about ice ages and rapid changes that preceded/followed them) as there are plenty of positive feedback mechanisms. However, it is quite conceivable that at the end, with respect to development of tropical systems, it might be a wash. I would not bet too much on that, though.

[x-y-no]

Cold water is denser, but fresh water is less dense. Introduction of this fresh water can disturb thermohaline circulation in north atlantic: warm salty tropical waters come with the gulf stream, get cooled up north and sink, 'sucking' in more warm water. Once the salty formerly warm water gets diluted with fresh water, the sinking tendency is not that strong and the gulf stream might actually get switched off. Don't ask me what would that mean - probably nothing good: much colder up north, but the warm water would stay down south. More thermal gradient = more severe weather

All the research I've seen indicates that the rater of freshening we are seeing or are likely to see even in the relatively stronger GW scenarios is unlikely to result in a complete shutdown. The past episodes were triggered by much more rapid influxes of fresh water (sudden draining of large inland lakes into the north Atlantic).

Alternatively, the gulf stream is not switched off and the artic keeps warming, due to positive feedback: onec ice has melted, the water up there will be warmed by the sun, alse methane will be released from permafrost.

That's a much more likely scenario. The size of this positive methane feedback is a major unknown.

How would that influence tropical development nobody knows - the waters down south will be warmer, the question is what would be temperatures in the upper troposphere (that's the radiator of a hurricane - it is a heat engine after all). Perhaps more importantly what would be the prevailing environment - shear, SAL, generation of cape verde waves etc.

Well, the lapse rate wouldn't change significantly,, but yes the dominant upper-air patterns certainly might - and it's unknown what net effect that would have on cyclogenesis.

Saying that changes up north would almost certainly NOT affect tropical development is wishful thinking and/or ignorance, at best. The effects will be there and easily might be quite strong (atmosphere and oceans are complex dynamical systems with chaotic tendencies - study a bit about ice ages and rapid changes that preceded/followed them) as there are plenty of positive feedback mechanisms. However, it is quite conceivable that at the end, with respect to development of tropical systems, it might be a wash. I would not bet too much on that, though.

Can't argue too much with that.

[Derek Ortt]

it would create a lower albedo, but only in the polar regions. So the waters would be warmer there

It may increase the negative phases of the thermohaline circulation, since that involves bringing up of the cooler waters. With more cold melted ice, that would provide more in the way of cooler waters.

The overall effect would be small, maybe 1 storm less per year