Why Focus on the Polar Regions for impacts from Sea Level Rise? Margie Turrin Lamont-Doherty Earth Observatory of Columbia University
Sea Level has to do with water storage 20,000 yrs ago at the end of the last ice age sea level was about 400 B. lower than today. Over 14,000 years it rose that 400 B. and then stabilized ~6000-8000 yrs. ago where it stayed for most of human history Over the last few hundred years we have warmed the atmosphere and started to accelerate the mellng of the ice regions causing sea level rise to accelerate. So where is the future SLR stored
The Polar Regions Antarctica & the Arctic - the literal ends of the Earth South North LOCATION KEEPS THEM COLD AND COVERED IN ICE. ElevaLon maps
Facts About the An ice sheet is a mass of land-based glacial ice extending over 50,000 sq kms (20,000 sq. miles ~2.5 times size of NJ) Two remaining ice sheets on Earth 1 at each pole. Arctic Greenland: ~ 3 times the size of Texas, and >75 times bigger than NJ. Ice sheet covers ~80 % of Greenland. The ice sheet is over 2 miles thick Greenland s ice sheet began to form ~ 3 to 4 my ago
Camp Raven in the Center of Southern Greenland. Sign reads PopulaLon 2 for the permanent science team there! Facts About the An ice sheet is a mass of land-based glacial ice extending over 50,000 sq kms (20,000 sq. miles ~2.5 times size of NJ) Two remaining ice sheets on Earth 1 at each pole. Arctic Greenland: ~ 3 times the size of Texas, and >75 times bigger than NJ. Ice sheet covers ~80 % of Greenland. The ice sheet is over 2 miles thick Greenland s ice sheet began to form ~ 3 to 4 my ago Photo: Margie Turrin
Beneath the ice the land elevalon shows a ring of mountains and the center pressed down below sea level by all the ice. Around the edges are areas with incised trenches carved into the shelf carrying warm deepwater up the \ords allowing melt.
1 Facts About the Antarctica - Ice sheet is 14 million sq kms (5.4 million square miles) ~1.5 times size of the continental U.S. The ice sheet is up to 3 miles thick & covers 97% of the continent There has been permanent ice on Antarctica for ~35 my old oldest ice found there is 800,000 yrs. old
1 Facts About the Antarctica - Ice sheet is 14 million sq kms (5.4 million square miles) ~1.5 times size of the continental U.S. The ice sheet is up to 3 miles thick & covers 97% of the continent There has been permanent ice on Antarctica for ~35 my old oldest ice found there is 800,000 yrs. old Photo: Margie Turrin
If you remove the ice from AntarcLca you see that much of the land has been pushed down below sea level. Anything in blue or green is pushed below sea level by ice and more exposed to melt from warming ocean water.
Greenland s Kangerdlugssuaq Glacier, photo by P. Spector Glaciers form where snow remains year-round, compressing into ice over Lme. Glacier AccounLng is like a bank account with ice leaving & being replaced. They remain balanced (equal in size) if each year the snow being added equals the snow being lost; They grow when more is added (snow) than removed (melt); They shrink when more is removed (melts) than added (snow).
One important reason to focus on the polar regions is their conneclon to global sea level Photo: Margie Turrin
From 1992-2010 the SLR contribulons came from Ocean Warming/Thermal Expansion 50% MelLng Ice/Cryosphere 50% Small Glaciers 27% but overall there is only 0.5 meters of SLR in small glaciers Greenland 12% AntarcLca 9%
The vast potenlal for future Sea Level Rise is from the two polar ice sheets
Greenland 24 B. West AntarcLca 21 B. & East AntarcLca has most sea level contribulon 170 B. Sea Level Rise PotenLals
We have four separate lines of evidence for loss of land ice, each collected by a different satellites 1. More days of ice melt (warming) 2. Ice is speeding up moving faster off the land (areas increasing 30 meters/yr) 3. Ice is losing elevalon & retrealng (meters/yr) 4. Ice is losing mass weighing less
Evidence #1: Increased Melt Days in Greenland
Increase in number of meltwater ponds forming on the surface of the ice, & found at higher elevalons on the ice sheet Arctic - Melt Ponds Photo: Margie Turrin Finding a weakness in the ice they can drain quickly moving meltwater to the base of the ice sheet lubricating it and causing melt at the base and sliding.
Evidence #2: AcceleraLng Glacial Flow Pine Island Glacier, AntarcLca @~31 B/day Jakobshavn (Ilulissat) Glacier, Greenland moving @~113 B./day!
Jakobshavn Glacier Greenland Fjord Developing from RetreaLng Jakobshavn Glacier 1851-2014 (credit: NASA)
Deep cut \ords like Jakobshavn Glacier can move ice out to the ocean from the land Photo: Margie Turrin
Evidence #3: Loss of elevalon in ice Note: snow accumulalon in this region is ~ 1m/yr Delta in elevalon ( Meters) 5 0-5 -10-15 -20 Distance in kilometers Baseline is Nov. 2003 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 April 2007 Oct. 2007-25 Graph of Pine Island Glacier elevalon loss 2003-2007 data from IceSat
Evidence #4: Losing Mass
Evidence #4: Losing Ice Mass
What About the Glaciers? They have been experiencing massive change Losing mass from almost all glaciers, including those getting more snow each year. Sea Level Equivalent (SLE)
Photo credit Kenjai Fjords NaLonal Park
Credit Bruce Molnia, USGS Pedersen Glacier retreated more than 0.6 miles and thinned as much as 350 feet between the mid-1920's and August 10, 2005.
Muir Glacier, Alaska, August 13, 1941, photo by W.O. Field
Muir Glacier, Alaska, August 31, 2004, photo by B.F. Molnia Muir Glacier retreated more than 25 miles between June 1899 and September 2003. By 2000, it was no longer a Ldewater glacier. Muir Inlet now exists in the area formerly occupied by the glacier Muir Glacier, Alaska, August 13, 1941, photo by W.O. Field
Photo: M.T. Millet, Glacier Bay NaLonal Park people
people people Photo Photo: by M.T. R.D. Millet, Karpilo, NaLonal Park Glacier Service Bay NaLonal Park Plateau Glacier retreated more than 3 miles and thinned as much as 1,200 feet between 1961 and 2003. It no longer exists.
Alaskan Glaciers losing mass from 1994-2013 Losing 75 billion tons of ice per year over this period
Ac#vity Links Polar Explorer: Sea Level App that we used is a free downloadable ios app www.polarexplorer.org Online version: hap://www.polar-observer.org/data/web_pages/polarexploreronline.html Sources for community assessment virtual walk: hap://sealevel.climatecentral.org/maps (& Risk Zone Map) Second Source: hap://www.scenichudson.org/slr/mapper (see layers - wetlands, community, municipal assets, brownfield/ hazmat sites) Source for Planning Informa#on: hap://library.rpa.org/pdf/rpa-under- Water-How-Sea-Level-Rise-Threatens-the-Tri-State-Region.pdf