mar110 lecture #32 global warming, sea ice & sea leve · 3 december 2008 mar 110 lecture 32...

3 December 2008 MAR 110 Lecture 32 Warming, Sea Ice Melting, and Sea Level 1

MAR110 LECTURE #32 Global Warming, Sea Ice & Sea Leve

Late 19Late 19thth Century Melting of Little Ice Age IceCentury Melting of Little Ice Age Ice

Ernest Ernest ShackletonShackletonExplores Explores

Antarctica 1915Antarctica 1915

The Titanic takes The Titanic takes an April 1912 an April 1912

“Cruise”“Cruise”

Figure 32.2 The Little Ice Age Transitions to Warming The Little Ice Age ( ~1350 to 1850) abruptly transitioned to a warming trend that persists to present day. The large amounts of polar region ice that accumulated during the Little Ice Age, began to break up, creating expanded fields of icebergs. The Titanic disaster occurred because of the reduced respect for the ice. The less permanent ice in and around Antarctica sparked a race to the South Pole (ItO)

PostPost--GlaciationGlaciationWarmingWarming

Figure 32.1 Post Glaciation Northern Hemisphere Warming (XXXX)


Figure 32.3a North Atlantic Sea Ice Icebergs populated the North Atlantic trade routes in April 1912 (??)

Figure 32.3b Titanic’s Fateful Cruise The path of the Titanic before it sank after hitting an ice berg 14 April 1912. (??)


Figure 32.5 Global Warming Continues to Present Day (NG 3-98)

Figure 32.4 Endurance Trapped in the Antarctica Ice In a 1916 attempt to be the first human to reach the South Pole (by land), Ernest Shackleton expeditionary ship –the Endurance - got caught in the ice surrounding Antarctica. Shackleton’s exploits are documented in his book entitled “South” (ES)


“Recent” WARMING is a FACT

“Recent” Carbon Dioxide increase is a FACT

ARE THEY RELATED?

Figure 32.7 Evidence of Global Warming & CO2 Increase (NG 3-98)

EVIDENCE of WARMINGEVIDENCE of WARMING

Figure 32.6 Evidence of Global Warming (NG 3-98)


The The Greenhouse Greenhouse

EffectEffectAnalogyAnalogy

EarthEarth’’ssLong Wave Long Wave RadiationRadiation

..trapped by..trapped by

““Greenhouse Greenhouse GasesGases””

Figure 32.9 Analogy: Greenhouse Warming (NG 3-98)

EarthEarth’’s s Long Wave Infrared RadiationLong Wave Infrared Radiation

..trapped by ..trapped by ““Greenhouse GasesGreenhouse Gases””

Figure 32.8 Fundamentals of Global Warming & CO2 Increase (NG 3-98)


No matter the cause

GLOBAL WarmingHAS CONSEQUENCES !

Sea Level Rise is one of them

QUESTIONS regarding GLOBALWARMING

How much is due to: ….a “LONGER-TERM” NATURAL CYCLE ?

……..HUMAN ACTIVITIES ?

Figure 32.10 Global Warming Causes & Consequences? (NG 3-98)

The Last 20,000 Years The Last 20,000 Years Global Sea Level RiseGlobal Sea Level Rise

Figure 32.11 Coastline Changes Due to Sea Level Rise Florida During the past 20,000 years sea level rise has changed the coastlines of Florida and SE Asia. (ItO)


THE ARCTIC ICETHE ARCTIC ICE

Submarine Trip Submarine Trip Under Arctic Ice CoverUnder Arctic Ice Cover

Figure 32.13 Northern Hemisphere Ice Cover (upper panel) People have been looking for a northern ocean route to Asia for hundreds of years. However, persistent Arctic sea ice has foiled those plans. Except for submarines (the Nautilus in this 1958 case) ships have been unable to traverse the region. However the size of the Arctic ice pack is thinning. (NG).

LOOKING LOOKING forfor

an ARCTIC an ARCTIC SHIPPING SHIPPING

LANE:LANE:

1500 1500

Figure 32.12 Northern Hemisphere Ice Cover (upper panel) People have been looking for a northern ocean route to Asia for hundreds of years. However, persistent Arctic sea ice has foiled those plans..


Figure 32.14 Sea Ice and Climate (O)


Figure 32.16 Recent Sea Level Change Between 1992 and 2002 global sea level rose at an accelerating rate about 20 millimeters (2 cm ~ 1 inch) per decade. The melting of land-grounded ice is contributing to this rise.

NA Ice NA Ice Cover Cover

EvolutionEvolution

19791979 20032003

Figure 32.15 Northern Hemisphere Ice Cover Evolution (upper panels) Receding glacial ice cover - 21 to 14 ky BP. (lower panels) In recent decades, arctic ice has been melting at an increasingly more rapid rate during summer and has not been regenerated during the winter. Note the change from 1979 to 2003. Greenland ice is of particular concern because melting of its land-based ice will contribute to sea level rise (NG ??).


IF …IF …the TOTAL the TOTAL AntarcticAntarctic

& & Greenland Greenland Ice Cover Ice Cover Melted,Melted,

THEN..THEN..CatastropicCatastropicSeaSea Level Level

Rise!Rise!

Figure 32.18 Catastrophic Sea Level Rise

Antarctic Antarctic Ice Cover Ice Cover EvolutionEvolution

earlyearly20022002

Larson Ice Shelf CollapseLarson Ice Shelf Collapse

OneOneMonthMonthLaterLater

SeasonalSeasonalEvolutionEvolution

Figure 32.17 Ice Melting and Sea Level Change Between 1992 and 2002 global sea level rose at an accelerating rate about 20 millimeters (2 cm ~ 1 inch) per decade. The melting of land-grounded ice is contributing to this rise.


Figure 32.2 Ice Cover During the last major Glaciation 20ky BP Thick Ice overran significant portions of North America and Northern Eurasia. (XXXX)

Global Sea Level RiseGlobal Sea Level RiseFuture? Future?

Figure 32.19 Future Florida Coastline?


Figure 32.3 Ice Cover during the last major Glaciation 20ky BP. At the height of the last major glaciation, significant portions of North America and Northern Eurasia were covered with thick ice. (XXXX)

MultipleMultiple--GlaciationsGlaciations -- Past 450,000 yearsPast 450,000 years

Ice Ice Formation Formation

Lowers Lowers Sea LevelSea Level

Figure 32.1 Multiple-Glaciations During The Past 450,000 years The fresh component of seawater is converted to glacial ice. Thus when glaciers grow with decreased global temperatures, sea level drops as indicated for several occasions over the past 150,000 years. (XXXX)


THE RACE FOR THE THE RACE FOR THE SOUTH POLESOUTH POLE

Sir Ernest Sir Ernest Shackelton’sShackelton’sAttempt: 1908Attempt: 1908--0909

Figure 32.11 Sir Ernest Shackleton: 1908-09 To save his men, Shackleton had to turn back in his attempt to walk to the South Pole - 97 miles short. Later Robert Scott - the first person to reach the South Pole over land- died with his men on their return trip to the coast. Robert Amundsen was the first person to reach the South Pole and return -1916. (S)

Late 19Late 19thth Century Melting of Little Ice Age IceCentury Melting of Little Ice Age Ice

Ernest Ernest ShackletonShackletonExplores Explores

Antarctica 1915Antarctica 1915

The Titanic takes The Titanic takes an April 1912 an April 1912

““CruiseCruise””

Figure 32.2 Global Cooling and Warming During Past 1000 years. Little Ice Age ice began to melt about 1860. However the ice presented problems for the Arctic and Antarctic explorers as well as the Titanic(XXXX)


THE RACE FOR THE THE RACE FOR THE SOUTH POLESOUTH POLE

Sir Ernest Sir Ernest Shackelton’sShackelton’sAttempt: 1908Attempt: 1908--0909

Figure 32.12 Sir Ernest Shackleton: 1908-09 To save his men, Shackleton had to turn back in his attempt to walk to the South Pole 97 miles short. Later Robert Scott was the first person to visit the South Pole, but he and his men died on the return trip. Even later, Robert Amundsen got to the South Pole and returned. (S)


Figure 32.15 The Endurance is Crushed After being trapped in the ice for about a year, the ice pressure became so large that the ship was crushed. The two photos were taken only three hours apart. (ES)

Shackelton’sShackelton’s “Antarctic Expedition” “Antarctic Expedition” -- ENDURANCE ENDURANCE -- 19141914--1916 1916

Figure 32.13 Shackleton’s “Antarctic Expedition” : 1914-16 Sir Ernest Shackleton’s expedition “to the South Pole” on the ENDURANCE was trapped in the ice for more than a year. He then had to make one of the most arduous and heroic journey’s across the open sea to save his men. (S)


Shackelton’sShackelton’s ““Race”toRace”to South Georgia in the CairnSouth Georgia in the Cairn

Figure 32.17 Saving Shackelton’s Men 1916 Shackelton and three of his men (Crean, Wild, and Hurley) sailed the 30ft dory James Caird from Elephant Island across 650 nm of open ocean, during 2 ½ weeks in early southern hemisphere winter (April-May 1916), to South Georgia Island - one of the most arduous and heroic journey’s in history. (ES)

Shackelton’sShackelton’s “Gang of Four” Departs Elephant Island “Gang of Four” Departs Elephant Island

Figure 32.16 Saving Shackleton’s Men 1916 Shackleton’s expedition “to the South Pole” on the ENDURANCE was trapped in the ice for more than a year. After surviving that and in order to obtain rescue help for his men, he and four of his men embarked on a sail in the dory James Caird from Elephant Island across 600 miles of open ocean to South Georgia Island. (ES)


TrekTrek Across South GeorgiaAcross South Georgia

Figure 32.19 The Walk Across South Georgia. The four men traversed walk the mountainous island (see amp) to the whaling station (ES)

The The James James CairdCaird Ashore on South GeorgiaAshore on South Georgia

Figure 32.18 The James Caird Ashore on South Georgia Island. After tacking against the wind to make harbor (see map), and after pulling their boat “safely” ashore, the four men prepared to walk across the mountainous island to the whaling station (ES)


Figure 32.11a Florida Sea Level - 20,000 Years BP Florida was considerably larger at the height of the last global glaciation. (XXXX)

Figure 32.20 The Rescue. Shackleton rescues his men on Elephant Island! - 30 days after the James Caird departed. (ES)


Figure 32.11b Southeast Asia Sea Level 20,000 Years BP A 100m lower sea level at the height of the last global glaciation caused the formation a large land mass where and present-day SE Asia and Indonesia are. (XXXX)

Warming Warming &&

Receding IceReceding Ice

Cape Cod BayCape Cod Bay15,000 BP15,000 BP

Section ASection A--BB

Figure 32.7 Warming and Receding Ice Cape Cod Bay 15,000 BPThe glacial ice and land forms along transect A-B in the upper panel are profiled in the lower panel. Note that the ice is grounded across the lake north of the terminal moraine that forms the backbone of Cape Cod, Martha’s Vineyard and Nantucket. (ItO)

mar110 lecture #32 global warming, sea ice & sea leve · 3 december 2008 mar 110 lecture 32...

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