MELTING GLACIERS
Global Warming According to the recent IPCC report, the mean global surface temperature has increased by 0.74 O C over the last 100 years ( ) 11 of the 12 warmest years have been recorded in the past 12 years
Findings of the IPCC Assessment Report (2007) There has been a significant decline in the mountain glaciers and snow cover, which has contributed to the increased sea levels From 1961 to 2003, the global mean sea level rose by 1.8 (+0.5) mm per year The global temperature of the oceans increased by 0.10 o C from surface to depth of 700m from and 80% of the heat added to the climate system is being absorbed by the ocean Other long term climatic changes that have been observed include extreme droughts, intensity of tropical cyclones, changes in the salinity of the ocean and wind patterns
Changes in the precipitation pattern : IPCC Report (2007) Precipitation has significantly increased (+) in eastern North and South America, northern and central Asia and northern Europe There has been decline (-) in precipitation in the Mediterranean, some regions in southern Asia, southern Africa and Sahel
Melting of the Greenland Ice Sheet According to NASA scientists, the Greenland ice sheet is melting faster than it is being replaced, contributing to sea level rise The loss of ice from Greenland doubled between 1996 and 2005 From 1996 to 2000, the largest acceleration and mass loss came from southeast Greenland From 2000 to 2005, the trend extended to include central east and west Greenland It is estimated that 69 per cent of the ice-mass loss in recent years came from eastern Greenland
Greenland ice is declining faster than expected Between 2003 and 2005 the low coastal areas of Greenland lost 155 gigatons of ice per year due to excess melting while the high elevation interior gained 54 gigatons annually from excess snowfall Between 2004 and 2006, the rate of melting accelerated, with the massive ice sheet melting two and one-half times faster than the previous two-year period Greenland lost roughly 164 cubic miles of ice from April 2004 to April 2006—more than the volume of the North American Great Lake Erie
Greenland Ice Sheet Dramatic ice mass losses concentrated in the low- elevation coastal regions, with nearly half of the loss coming from southeast Greenland NASA Earth Observatory
Greenland Ice Sheet Greenland is now losing 20 percent more mass than it receives from new snowfall each year. NASA Earth Observatory
Greenland Ice Sheet University of Colorado, CIRES
Melting of ice in Greenland : A significant increase in the melting area has been observed along the edge of the ice cap in Greenland. NASA Earth Observatory
Retreat of Ice and Snow in Greenland NASA Earth Observatory Ice loses in Greenland range from 5 to 25 centimeters of water equivalent per year
This May 2005 picture of Helheim Glacier, demonstrates high calving activity associated with faster glacial flow Helheim glacier, located in southeast Greenland, is now one of the fastest moving glaciers in the world : These images show the retreat of Helheim glacier’s calving front Calving of Helheim Glacier, Greenland The glacier’s peak rate of flow has increased from 8 km/yr in 2000 to 11 km/yr in 2005
Dramatic changes in Arctic Sea Ice Imagine an ice-free Arctic
Evidence of extensive snowmelts in West Antarctica January 2005: Areas of extensive snowmelt (shown in yellow and red) have been discovered by a team of NASA and university scientists in response to warmer temperatures in west Antarctica. The combined area affected is as big as California. NASA Jet Propulsion Laboratory
Breakup of Larsen ice shelf (Antarctic Peninsula) 220 metres thick Larsen B shelf existed for at least 400 years prior to breakup
Disintegration of the Larsen B Ice Shelf, Antarctic Peninsula The ice shelf disintegrated suddenly in March 2002 due to warm summer temperatures NASA Earth Observatory
Breakup of Antarctica’s Ross Ice Shelf An iceberg (B-15J) of size of a small United States state cracked off the Antarctica’s Ross Ice Shelf in March 2000 On February 1, 2007, three new icebergs were formed due to the break up of the original iceberg NASA Earth Observatory
Breaking Off Filchner Ice Shelf Antarctica Filchner Ice Shelf is the largest ice shelf on the planet In 1986 the front edge of Ice Shelf broke off into three enormous icebergs
Calving of Ninnis Glacier Antarctica 22 January 2000: The Ninnis Glacier Tongue soon after the initial calving 5 February 2002: Iceberg split into two sections and started moving away from Ninnis Glacier
Cracks on Drygalski Ice Tongue Antarctica The ice tongue was discovered in February 2005: Drygalski calved an iceberg Image shows cracks formed by time and ocean currents
Shrinking Lake Chad shared by Nigeria, Niger, Chad and Cameroon Persistent drought has shrunk the lake to about a tenth of its former size 1972: Larger lake surface area is visible in this image 2001: Due to regionally drying climate and human demand for fresh water, Lake Chad is fraction of what is once was 2004: In many places, the green of wetlands is being replaced by drifting sand dunes (tan ripples mixed with green)
Shrinking Breidamerkurjökull Glacier Iceland : Images show glacier has receded and the glacial lake at its tip has enlarged
North America: Angangueo 1986: Images show Degradation of forest area 2001: Between 1984 and 1999, 38 per cent of forests were degraded Ice dam in the Hubbard Glacier, United States 1985 –Hubbard Glacier 1986 –Hubbard Glacier blocks Russell Fjord 2002 –Hubbard Glacier blocks Russell Fjord again 2003 – Glacier has retreated
North America: Angangueo 1986: Images show Degradation of forest area 2001: Between 1984 and 1999, 38 per cent of forests were degraded Hubbard Glacier advances United States 14 Aug Aug 2002
North America: Angangueo 1986: Images show Degradation of forest area 2001: Between 1984 and 1999, 38 per cent of forests were degraded Retreat of Columbia Glacier, Alaska and Arapaho Glacier, Colorado, United States NASA Earth Observatory Since 1980, the Columbia glacier has retreated about 15 kilometers but its retreat has not been directly linked to rise in global temperatures Arapaho glacier has thinned by 40 meters since 1960
North America: Angangueo 1986: Images show Degradation of forest area 2001: Between 1984 and 1999, 38 per cent of forests were degraded Athabasca Glacier, Canada Athabasca glacier has receded more than 1.5 kilometres in last 125 years It has lost half of its volume NASA Earth Observatory About 8000 cubic kilometres of ice have been lost by glaciers worldwide since 1960.
North America: Angangueo 1986: Images show Degradation of forest area 2001: Between 1984 and 1999, 38 per cent of forests were degraded Glacier National Park, Montana, United States The glaciers are one-third their size in 1850 Scientist predict that all the glaciers will disappear by 2030 NASA Earth Observatory Only 37 glaciers exist compared to 147 glaciers, 150 years ago 10 Aug July July 2001
North America: Angangueo 1986: Images show Degradation of forest area 2001: Between 1984 and 1999, 38 per cent of forests were degraded Glacier National Park, Montana, United States
North America: Angangueo 1986: Images show Degradation of forest area 2001: Between 1984 and 1999, 38 per cent of forests were degraded Glacier National Park, Montana, United States
North America: Angangueo 1986: Images show Degradation of forest area 2001: Between 1984 and 1999, 38 per cent of forests were degraded Ayles Ice Shelf, Ellesmere Island, Canada Ayles Ice Shelf on Ellesmere Island, broke free on August 13, 2005 and drifted out to the sea NASA Earth Observatory
Declining Rwenzori Mountain Glaciers in East Africa : Images show a gradual decrease of the glacial area, especially on the peaks This decline is attributed to increased air temperature and decreased accumulation and convective cloud activity
Disappearing Icecap of Mt. Kilimanjaro, Tanzania Africa’s highest mountain with a forest belt having rich diversity of ecosystems 1976: Glaciers covered most of the summit 2000: The glaciers had receded alarmingly
Retreat of Gangotri Glacier, India NASA Earth Observatory Gangotri glacier has retreated more than 850 metres, in the last 25 years It has retreated more than 76 metres from 1996 to 1999
Glacial Lakes and Glacial Lake Outburst Floods Jeffrey Kargel, USGS/NASA JPL/AGU Glacial lakes are formed due to the melting of ice and snow from glaciers Due to the faster rate of melting from the glaciers, possibly due to global warming, water is accumulating at an increasing rate in these lakes Sudden outburst results in Glacial Lake Outburst Flood (GLOF) downstream causing destruction of life and property Glacial Lakes in the Bhutan-Himalaya Region
Retreat of Upsala Glacier, Argentina NASA Earth Observatory The Upsala glacier has retreated more than 4 kilometres since late 1960’s to mid 1990’s and continues to retreat January 2004 position
Retreat of San Quintin Glacier, Chile NASA Earth Observatory The San Quintin Glacier appears to be losing mass and retreating
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