Global Climate Change: A Paleoclimate Perspective from the World’s Highest Mountains 2008 Jim Arnold Lecture UC San Diego, May 9, 2008 Lonnie G. Thompson University Distinguished Professor School of Earth Sciences & Byrd Polar Research Center The Ohio State University Ice Core Paleoclimate Research Group Ellen Mosley-Thompson Funding provided by: Henry Brecher NSF: Paleoclimatology & Polar Mary Davis Programs Paolo Gabrielli NASA: Earth Sciences Ping-Nan Lin NOAA: Paleoclimatology Matthew Makou Comer Foundation Victor Zagorodnov Graduate Students: Liz Birkos, Aron Buffen, Natalie Kehrwald, David Urmann, Lijia Wei Objectives: • Introduction to climate change • Glaciers, among the first responders to global warming, serve as both indicators and drivers of climate change • Evidence for abrupt climate change, past and present • Evidence for recent acceleration of the rate of ice loss in the tropics – A Clear and Present Danger! • Options: prevention, adaptation and suffering • Conclusions Our Earth is warming! Environmental conditions are changing! - some changes are unprecedented for thousands of years - some changes are occurring rapidly (years to decades) (shrinking sea ice, ecosystem disruptions, retreating and melting glaciers) 2005 warmest year on record 0.7°C relative to the 1961-1990 mean http:www.giss.nasa.gov/research/news Natural mechanisms influence climate Natural mechanisms • Changes in the Sun • Changes in the amount of volcanic dust in the atmosphere • Internal variability of the coupled atmosphere-ocean system (e.g., ENSO, monsoon systems, NAO) Human factors also influence climate Non-natural mechanisms • Changes in the concentrations of atmospheric greenhouse gases • Changes in aerosols and particles from burning fossil fuels (sulfate aerosols) and biomass (black carbon) • Changes in the reflectivity (albedo) of the Earth’s surface Smoke from fires in Guatemala and Mexico (May 14, 1998) Earth’s ice sheets and glaciers preserve long, high resolution histories High temporal resolution East Antarctica Plateau Long records 20021977 Quelccaya Ice Cap, Peru Ice cores are powerful contributors to multi-proxy reconstructions: 1) they provide multiple lines of climatic & environmental evidence 2) ideal for revealing rapid climate changes (δ18O, δD) Guliya ice cap, Tibet Class-100 clean room houses the equipment to analyze dust, isotopes and chemicals Freezers for storage and cold rooms for physical property measurements Machine shop for fabrication of our drills Vostok The Vostok ice core extends back through multiple glacial and interglacial stages - recording the changes in the composition of the Earth's atmosphere Today: Today: 385 CO2 is 385 ppmv CO2 is 378 ppmv CH4 is 1750 ppbv CH4 is 1750 ppbv Houghton et al., 2001 Petit et al., 1999 Carbon dioxide and methane concentrations: Past, present and future By 2100: CO2 remains in the 850 CO2 ~ 850 ppmv atmosphere from 70 to 120 years IPCC 2000 Scenario A1B for 2100 AD By 2100: CH4 ~ 3700 ppbv Today: CO is 385 ppmv 385 2 CH4 is 1750 ppbv Houghton et al., 2001 Petit et al., 1999 Proxy Records Provide A Critical Time Perspective 5 IPCC 4th Assessment (2007) Projection for 2100 AD 4 2.0 – 4.5 oC 3 2 Global Temperature (°C) Northern Hemisphere N.H.Temperature Temperature (°C) (°C) 1 0.4 0 0 -0.4 -0.8 1000 1200 1400 1600 1800 2000 YearYear (A.D.) A.D.. 11 Ice cores provide unique histories …… from regions where other recording systems are limited or absent Huascarán, Peru Dasuopu Glacier Southern Tibet Sites where the OSU team has drilled ice cores DUNDE ICE CAP, CHINA CORE SITES, 1987 SUMMIT CORES D UNDE IC E CAP, C HINA SUMMIT CORECORES SITE, 1987 EQUILIBRIUM LINE EQUILIBRIUM LINE South America BPRC1 Ice core drilling on the Coropuna Ice Cap, Peru (2003) Coropuna, Peru Chironomidae 1260± 380 yr. B.P. length: 0.7 mm Sajama, Bolivia Heteroptera 5620 ± 275 yr. B.P. length: 2.0 mm Side of Quelccaya ice cap, Peru Annual layers -12 -14 -16 -18 per mil per -20 -22 Quelccaya 2003 Summit Dome -24 Average of Quelccaya 1983 cores 1550 1575 1600 1625 1650 1675 1700 1725 1750 1775 1800 1825 1850 1875 1900 1925 1950 1975 2000 Year -12 -14 -16 -18 -20 O annual averages 18 -22 δ -24 R2= 0.82 2003 -26 -26 -24 -22 -20 -18 -16 -14 -12 -10 1983 δ18O annual averages Tropical Composite (Temperature) Tropical Composite (Precipitation) 77 new High elevation, low latitudecores ice cores record - large-scale climate changes - regional differences No LIA No MWP LIA MWP Thompson et al., PNAS, 2006 77 new High elevation, low latitudecores ice cores record - large-scale climate changes - regional differences No LIA No MWP LIA MWP Thompson et al., PNAS, 2006 77 new High elevation, low latitudecores ice cores record - large-scale climate changes - regional differences Reference period (1961 – 1990 A.D.) LIA MWP ThomThompsonpson et al.et ,al. PNAS, PNAS,, 2006 2006 McCall Glacier, Brooks Range, Alaska Austin Post,1958 Matt Nolan, 2003 Muir Glacier, SE Alaska August, 1941 (photo by William Field) August, 2004 (photo by Bruce Molnia) AX010, Nepal 1989 Himalayas, 1978 1998 2004 Photos: Koji Fujita Massive retreat of low-latitude glaciers today 2002 Gangapurna Glacier Courtesy Doug Burbank, UCSB Massive retreat of low-latitude glaciers today 2002 Gangapurna Glacier 1957 Courtesy Doug Burbank, UCSB ~ 2 - 3 m thinning / year Ghiacciai della Lobbia e dell’Adamello/Mandrone (102 anni) Foto: Archivio Storico – Biblioteca della Montagna SAT 1903 Foto: G. Alberti CGT 2005 Ghiacciaio de la Mare (71 anni) 2003 (Foto L. Carturan CGT) Zonal Distribution of Annual Precipitation Image from GOES-12 Satellite Nov 4, 2004 DJF Uniform tropical upper-air temperature DJF Larger SST variations DJF Rainfall roughly follows warm SST (Sobel and Bretherton, J. Climate , 2000 mos. relative to peak El Nino 1000-300 mb average air temperature anomalies associated with ENSO (MSU2) gray: 0.2-0.4 (peak Nino3.4) black: >0.4 K Warming spreads nearly uniformly around the tropics (Chiang and Sobel 2002, J. Climate) Aerial photo in 2000 Drill shelter on Northern Ice Field, Kilimanjaro in 2000 Kilimanjaro (2000) Northern Ice Field Core 3 Tube 1: top: 0.00 m Elongated bubbles Tube 43: top: 42.84 m Outburst of water and ice collapse on Fürtwangler Glacier (Kilimanjaro) in spring of 2003 16 Feb 2000 28 Jan 2006 15 Oct 2007 Furtwängler Glacier 16 Feb 2000 28 Jan 2006 15 Oct 2007 Himalayan glaciers store about 12,000 cubic kilometers of freshwater in ~15,000 glaciers and are the lifeline for millions of people (IPCC, 2007) Retreat of the Qori Kalis Glacier (Peru) 1978 – no lake 2004 – lake covers 78 acres Qori Kalis, July 2005 Qori Kalis, July 2006 2006 – lake covers 84 acres 1977 2006 Boulder, 1978 Boulder, 2006 Glaciers, especially tropical glaciers, are “the canaries in the coal mine” for our global climate system as they integrate and respond to most key climatological variables such as temperature, precipitation, cloudiness, humidity and radiation. • Global glacier retreat at the beginning of the 21st Century is driven mainly by increasing temperatures although regional factors (i.e., deforestation also may play a role). Martin Chambi J. Mid-1930’s Qoyllur Rit’i, Peru 2006 In 1915 Ernest Shackleton stated …… “What the Ice Gets, the Ice Keeps” But today the retreating ice is giving up long-buried secrets ….. Quelccaya, Peru 1977 2002 Quelccaya Ice Cap, 2002 200 – 400 m above its Plant modern range 5177 ± 45 yr. B.P. The Kilimanjaro ice cores provide a record ~ 11,000 years long This abrupt cooling event 5,200 years ago was contemporaneous with the reorganization of societal structures – Late Uruk abrupt climate change - Hierarchical societies formed in the overpopulated Nile Valley & Mesopotamia; - Neolithic settlements in the inner deserts of Arabia were abandoned Global, synchronous climatic change ~ 5 – 5.6 kyr B.P. Magny and Haas, 2004. J. Quat. Sci. • “One of the warning signs that a dangerous warming trend is under way in Antarctica will be the breakup of ice shelves on both coasts of the Antarctic Peninsula, starting with the northernmost and extending gradually southward.” • Concluding statement in Mercer, 1978 Nature Vol. 271 Temperatures in the Peninsula region have warmed ~2.0oC in the last 50 years. Part of the Larsen B Ice Shelf Jan 31 collapsed in 31 days (2002) Feb 23 Mar 3 Collapsing ice shelves don’t 10% Floating ice shelves do not directly raise sea level. contribute to sea level rise. 90% But, the loss of their buttressing effect, land-based glaciers flow faster and discharge more ice into the ocean raising sea level. Since 2002 some glaciers are now flowing 7 to 8 times faster. Some have thinned up to 40 meters in 6 months. Glaciers that feed the remaining parts of the ice shelves have not accelerated. Scambos et al., 2004 observations The warming in the Arctic is now well-documented ….. Arctic Climate Impact Assessment available at http://www.acia.uaf.edu/ East Greenland: summer melt water running into a moulin Photo by Roger J. Braithwaite Greenland – losing mass overall Gaining mass (increased precipitation) at high elevations Losing mass rapidly along coast Overall balance: -100 Gigaton (Gt) annually 360 Gt of water = 1 mm of eustatic sea level rise 82 Gt is ~1.5 months of Shepherd & Wingham, Science, 2007 U.S. water consumption West Antarctica & Peninsula – losing mass: - 50 to - 200 Gt annually East Antarctica – gaining mass: +25 to - 4 Gt per year Antarctica is losing mass: - 25 to -204 Gt annually 360 Gt of water = 1 mm of eustatic sea level rise 82 Gt = 1.5 months of U.S. water consumption Shepherd & Wingham, Science, 2007 Rignot et al., Nature Geoscience, 2008 In the last decade – many glaciers draining the two large ice sheets have accelerated their discharge to the ocean by 20 to 100% (highly variable).