Describe gain and loss budget associated with glaciers,including why and how global climate change is changing

Question

Describe gain and loss budget associated with glaciers,including why and how global climate change is changing

Answer 1

http://www.google.co.uk/search?aq=f&hl=e...

Answer 2

I am 77 and the climate has changed all my life.

Answer 3

Can't add much to JS's post, but I wanted to say a little bit about Antarctica.  There's been a lot of talk about the Eastern ice cap not melting, and actually thickening.  It's taken a while to track down, but here's how that looks to me.

The Eastern portion of the continent is a plateau, similar to Australia.  Snow falls there and compresses to form the ice.  The West is at a lower altitude, and slopes toward the sea.  Unlike the East, there are two gigantic bays or gulfs, separated by a huge peninsula.  These bays are covered with a layer of ice that extends for hundreds of miles from the continent.  This ice is hundreds of feet thick and floating on water, compared to the ice in the East that is miles thick, and sitting on bedrock.  It is this western ice that is melting, quite rapidly compared to predictions.  Now here's what's interesting:  From hundreds of miles inland there are these things called "streamers" which flow like rivers down to the ice shelf.  They are 20-30 miles wide, and hundreds of miles long.  Remarkably, they move pretty fast, around 1000 feet per day.  The ice shelves as they have been in the past melt at the edges, and reform seasonally.  Now we have continuous melting.  The ice shelves form a barrier, blocking and slowing the streamers when they meet.  Without the ice shelves, the streamers would flow unimpeded, and start to reduce the ice far inland, similar to what's going on in the Arctic.  This is where I would expect we will start to see changes in the East.

There is another effect that is worth noting.  Sea water is drawn under the shelves where it cools about 1/2 degree.  This makes it denser, and it shoots out at a good rate of speed to the North as more is drawn under.  These cold currents continue thousands of miles North.  One extends into the Indian Ocean, and moderates the temperature there.  Without the current, the Indian Ocean would just continue to slowly heat.  The other branch of the current swings east up the coast of asia to just North of Japan.  When the shelves are gone these currents will be gone too.  Major changes in climate will occur in the area of the Indian Ocean, and the Northeast coast of Asia.  Because these currents now also have a return leg that ties into other major currents in the conveyor, I would expect there would be major changes in the conveyor around the world when they are gone.

Oh Little RobberGirl, the link below is related to the matter you corrected me on a few days ago.  It does confirm what you said.  I think the conclusions in the 1970's were still right, but the time scale is way off.  I hope that isn't due to human activity since.

Answer 4

Glaciers are retreating much faster than they are accumulating new snow and ice, so their "budget" is in "defecit", and on average globally they are melting at acclerating rates.

The Antarctic has recently been measured to be losing total ice mass as well.  

"Over the 10 year time period of the survey, the ice sheet as a whole was certainly losing mass, and the mass loss increased by 75% during this time. Most of the mass loss is from the Amundsen Sea sector of West Antarctica and the northern tip of the Peninsula where it is driven by ongoing, pronounced glacier acceleration. In East Antarctica, the mass balance is near zero, but the thinning of its potentially vulnerable marine sectors suggests this may change in the near future."

http://www.sciencedaily.com/releases/200...

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Glacial evidence that the current rate of climate change sharply departs from rates measured in the past:

New Research Confirms Antarctic Thaw Fears - Spiegel Online

http://www.alertnet.org/thenews/newsdesk...

"...the Pine Island Glacier has shrunk by an average of 3.8 centimeters annually over the past 4,700 years. But the Smith and Pope glaciers have only lost 2.3 centimeters of their thickness annually during the past 14,500 years. Satellite measurements taken between 1992 and 1996, though, show a loss of 1.6 meters in thickness per year on the Pine Island Glacier -- a figure that represents 42 times the average melt of the past 4,700 years."

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Global warming threatens to dry up Ganges

http://www.boston.com/news/world/asia/ar...

"According to a UN climate report, the Himalayan glaciers that are the sources of the Ganges could disappear by 2030 as temperatures rise."

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http://www.salon.com/news/feature/2008/0...

According to both the 2001 and 2007 IPCC reports, neither Greenland nor Antarctica should lose significant mass by 2100. They both already are. Here again, the conservative nature of the IPCC process puts it at odds with observed empirical realities that are the basis of all science.

It's no surprise then that three scientific studies released in the past year -- too late for inclusion by the IPCC -- argue that based on historical data and recent observations, sea level rise this century will be much higher than the IPCC reports, up to 5 feet or more. Even scarier, the rate of sea level rise in 2100 might be greater than 6 inches a decade!

And it's no surprise at all that sea-level rise from 1993 and 2006 -- 1.3 inches per decade as measured by satellites -- has been higher than the IPCC climate models predicted.

The deniers are simply wrong when they claim that the IPCC has overestimated either current or future warming impacts. As many other recent observations reveal, the IPCC has been underestimating those impacts.

- Since 2000, carbon dioxide emissions have grown faster than any IPCC model had projected.

- The temperature rise from 1990 to 2005 -- 0.33°C -- was "near the top end of the range" of IPCC climate model predictions.

- "The recent [Arctic] sea-ice retreat is larger than in any of the (19) IPCC [climate] models" -- and that was a Norwegian expert in 2005. Since then, the Arctic retreat has stunned scientists by accelerating, losing an area equal to Texas and California just last summer.

- "The unexpectedly rapid expansion of the tropical belt constitutes yet another signal that climate change is occurring sooner than expected," noted one climate researcher in December.

Why are recent observations on the high side of model projections? First, as noted, most climate models used by the IPCC omit key amplifying feedbacks in the carbon cycle. Second, it was widely thought that increased human carbon dioxide emissions would be partly offset by more trees and other vegetation. But increases in droughts and wildfires -- both predicted by global warming theory -- seem to have negated that. Third, the ocean -- one of the largest sinks for carbon dioxide -- seems to be saturating decades earlier than the models had projected.

The result, as a number of studies have shown, is that the sensitivity of the world's climate to human emissions of greenhouse gases is no doubt much higher than the sensitivity used in most IPCC models. NASA's Hansen argued in a paper last year that the climate ultimately has twice the sensitivity used in IPCC models.

The bottom line is that recent observations and research make clear the planet almost certainly faces a greater and more imminent threat than is laid out in the IPCC reports.  That's why climate scientists are so desperate. That's why they keep begging for immediate action.

---

http://www.salon.com/news/feature/2008/0...

According to both the 2001 and 2007 IPCC reports, neither Greenland nor Antarctica should lose significant mass by 2100. They both already are. Here again, the conservative nature of the IPCC process puts it at odds with observed empirical realities that are the basis of all science.

It's no surprise then that three scientific studies released in the past year -- too late for inclusion by the IPCC -- argue that based on historical data and recent observations, sea level rise this century will be much higher than the IPCC reports, up to 5 feet or more. Even scarier, the rate of sea level rise in 2100 might be greater than 6 inches a decade!

And it's no surprise at all that sea-level rise from 1993 and 2006 -- 1.3 inches per decade as measured by satellites -- has been higher than the IPCC climate models predicted.

The deniers are simply wrong when they claim that the IPCC has overestimated either current or future warming impacts. As many other recent observations reveal, the IPCC has been underestimating those impacts.

- Since 2000, carbon dioxide emissions have grown faster than any IPCC model had projected.

- The temperature rise from 1990 to 2005 -- 0.33°C -- was "near the top end of the range" of IPCC climate model predictions.

- "The recent [Arctic] sea-ice retreat is larger than in any of the (19) IPCC [climate] models" -- and that was a Norwegian expert in 2005. Since then, the Arctic retreat has stunned scientists by accelerating, losing an area equal to Texas and California just last summer.

- "The unexpectedly rapid expansion of the tropical belt constitutes yet another signal that climate change is occurring sooner than expected," noted one climate researcher in December.

Why are recent observations on the high side of model projections? First, as noted, most climate models used by the IPCC omit key amplifying feedbacks in the carbon cycle. Second, it was widely thought that increased human carbon dioxide emissions would be partly offset by more trees and other vegetation. But increases in droughts and wildfires -- both predicted by global warming theory -- seem to have negated that. Third, the ocean -- one of the largest sinks for carbon dioxide -- seems to be saturating decades earlier than the models had projected.

The result, as a number of studies have shown, is that the sensitivity of the world's climate to human emissions of greenhouse gases is no doubt much higher than the sensitivity used in most IPCC models. NASA's Hansen argued in a paper last year that the climate ultimately has twice the sensitivity used in IPCC models.

The bottom line is that recent observations and research make clear the planet almost certainly faces a greater and more imminent threat than is laid out in the IPCC reports.  That's why climate scientists are so desperate. That's why they keep begging for immediate action.