Did the IPCC underestimate Antarctica sea-level influence?

Question

Dr. Eric Rignot http://quest.arc.nasa.gov/ltc/bios/eric_rignot.html

recently published a report in the journal Nature Geoscience regarding recent Antarctica ice mass losses.

http://www.nature.com/ngeo/journal/vaop/ncurrent/abs/ngeo102.html

According to this article:

http://www.reuters.com/article/environmentNews/idUSN1441637320080114

the latest IPCC report indicated Antarctica would not contribute significantly to sea-level rise because of expected precipitation increase. But Dr. Rignot's findings appears to contradict that.

So, was the IPCC report overly cautious regarding expected sea-level rise?

Answer 1

idk wat that is

Answer 2

the ice melting at antarctica is already in the water.  If it melts, it wont raise the sea level.

open sea will cause more water to evaporate than the sea ice surface, so the original thoughts were most likely correct.

Answer 3

The IPCC has admitted that their static model for ice sheet melt (like one giant ice cube) dramatically underestimates the melt rate, because real glaciers move, break up, and can rapidly accelerate due to the lubricating effect of meltwater.  That has been observed to be happening, and there are studies underway to enable us to better understand and model the process.

"Instead of sea levels rising by about 40 centimetres, as the IPCC predicts in one of its computer forecasts, the true rise might be as great as several metres by 2100. That is why, they say, planet Earth today is in 'imminent peril.'"

http://www.heatisonline.org/contentserve...

Here's confirmation that Antarctica is losing ice and the melt is accelerating:

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

Increasing Amounts Of Ice Mass Have Been Lost From West Antarctica

ScienceDaily (Jan. 14, 2008) — Increasing amounts of ice mass have been lost from West Antarctica and the Antarctic peninsula over the past ten years, according to research from the University of Bristol and published online recently in Nature Geoscience.

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...

ScienceDaily (Mar. 2, 2006) — University of Colorado at Boulder researchers have used data from a pair of NASA satellites orbiting Earth in tandem to determine that the Antarctic ice sheet, which harbors 90 percent of Earth's ice, has lost significant mass in recent years.

Just as there are a few qualified scientists who are frustrated that their skeptical views were not selected as the most likely scenario, many other qualified scientists were upset that the political review of the IPCC review softened and diluted their predictions, so the IPCC result could be considered to reflect a "middle of the road" compromise.  It displeases the special interests and outlying scientists on both sides, and that balance makes the IPCC's rather strong conclusion that mankind's greenhouse gasses are 90% sure to be responsible for current observed warming all the more sobering.

Answer 4

omg shoes

Answer 5

It sure sounds that way, and it wouldn't be the first indicator that the IPCC has been overly conservative in its projections (i.e. examples below).

One has to wonder how many times the IPCC has to be shown as too conservative before deniers will stop using the term 'alarmist'.

Answer 6

Probably...

The estimations used by IPCC on the rising sea levels "exclude(s) future rapid dynamical changes in ice flow". "Dynamical processes related to ice flow not included in current models but suggested by recent observations could increase the vulnerability of the ice sheets to warming, increasing future sea level rise. Understanding of these processes is limited and there is no consensus on their magnitude." "Larger values cannot be excluded, but understanding of these effects is too limited to assess their likelihood or provide a best estimate or an upper bound for sea level rise."[1]

Just because scientists can not model for the rapid changes, does not mean that these changes are not happening. In fact, direct observations prove that rapid changes are happening to Antarctica.[2][3]

Scientists were surprised at the speed at which the Larsen B Ice Shelf in Antarctica disintegrated in March 2002.[4] The prior understanding had been that the water sinks down into the mass of the ice and refreezes. In this case they found that instead of refreezing it tunneled and left the ice like Swiss cheese, metaphorically, and vulnerable to a sudden breakup.

Here is a good article on Antarctica glaciers:

"Antarctic ice riddle keeps sea-level secrets"

http://uk.reuters.com/article/environmen...