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Arctic Climate Variability in the Context of Global Change

Arctic Climate Variability in the Context of Global Change. Ola M. Johannessen, Lennart Bengtsson, Leonid Bobylev, Svetlana I. Kuzmina, Elena Shalina. Arctic from space. VARIATIONS OF THE EARTH'S SURFACE TEMPERATURE FOR THE PAST 1000 YEARS.

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Arctic Climate Variability in the Context of Global Change

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  1. Arctic Climate Variability in the Context of Global Change Ola M. Johannessen, Lennart Bengtsson, Leonid Bobylev, Svetlana I. Kuzmina, Elena Shalina

  2. Arctic from space

  3. VARIATIONS OF THE EARTH'S SURFACE TEMPERATURE FOR THE PAST 1000 YEARS

  4. TEMPERATURE CHANGES AS A RESPONSE TO GREENHOUSE GAS LEVELS INCREASING ANNUAL MEAN TEMPERATURE IS SHOWN THE RESULTS WERE AVERAGED FROM 19 CLIMATE MODELS USED TO PREDICT FUTURE CLIMATE BASED ON A 1% PER YEAR INCREASE IN GREENHOUSE GAS LEVELS. THE TEMPERATURE CHANGES ARE EXPECTED TO BE GREATER IN THE ARCTIC THAN AT LOWER LATITUDES.

  5. ZONALLY AVERAGED ANNUAL MEAN TEMPERATURE ANOMALIES observations

  6. TIME EVOLUTION OF CHANGES IN ZONALLY AVERAGED ANNUAL MEAN NEAR SURFACE TEMPERATURE for a) observations b) ECHAM4/OPYC GHG run c) ECHAM4/OPYC GSD run d) ECHAM4/OPYC CONTROL run

  7. 100% 90% 80% 70% 60% 50% 40% 30% 15% water land Monitoring ice concentration from microwave satellites water land TOTAL ICE COVER = MULTI-YEAR ICE + FIRST-YEAR ICE

  8. Arctic monthly total sea ice area : 1978-2002 14% decrease in September 5% decrease in March record-low summer ice coverage 6*106 km2 in September 2002

  9. Arctic total sea ice area anomalies: 1978-2002 1978-2002 – Trend: ~8x105 km2 (~-3% per decade)

  10. Microwave-derived multi-year ice area The results are obtained for five winter months (Nov-March). The negative trend is about 8.8% per decade, which is in good agreement with the results of J.Comiso: 7.1% per decade for MY ice extent and 9.2% per decade for MY ice area

  11. Satellite-based sea-ice concentration, 1978-2002: Mean ice concentration for (a) winter and (b) summer, Linear trends for (c) winter 50% decrease in the Barents and Greenland seas and (d) summer > 50% decreasein Beaufort and Chukchi seas, 30-50% in Siberaian marginal seas. September March

  12. Annual sea-ice extent and surface air temperature Annual sea-ice extent derived from Russian dataset(red), Walsh dataset(green) and (70-90°N) surface air temperature(black) r ~ 0.6

  13. Ice thickness data

  14. Arctic winter multi-year ice area vs. estimated ice thickness SMMR and SSM/I-derived Arctic winter MY ice area, and basin-wide ice thickness estimated from Russian drifting North Pole measurements of ice surface oscillations, 1978-1990. Correlation coefficient (r) ~ 0.88.

  15. OBSERVED AND ECHAM4-MODELLED NORTHERN HEMISPHERE SEA-ICE EXTENT IN MARCH (upper) AND SEPTEMBER (lower) The modeled scenarios include a control run (CRL), changes in greenhouse gases (GHG) and greenhouse gases plus sulfate aerosols (GSD).

  16. Climate model simulation of ice concentration due to CO2 doubling 2005 2085 Summer 80% decrease Ice concentration

  17. Climate model simulation of ice concentration due to CO2 doubling 2005 2085 Winter 20% decrease Ice concentration

  18. Temperature change ANIMATION

  19. Greenland Ice Sheet elevation changes Elevation changesfor 1992 - 2003 derived from merged ERS -1 and ERS -2 measurements Result: 5.4 ± 0.3 cm/year

  20. Elevation changes averaged over high- and low-elevation areas of Greenland Elevation growth is indicated over most of interior regions, while over margin areas ice sheet thinning is revealed

  21. snow cover ANOMALIES OF MONTHLY SNOW COVER OVER THE NORTHERN HEMISPHERE LANDS (INCLUDING GREENLAND) between November 1966 and January 2005 Visible satellite snow charts developed by David Robinson team show that negative anomalies of snow extent have dominated since 1987 THERE HAVE BEEN DECREASE OF ABOUT 10% IN THE EXTENT OF SNOW COVER SINCE THE LATE 1960s

  22. COMPOSITE OF OBSERVED VARIABILITY IN THE ARCTIC OCEAN-CLIMATE SYSTEM SINCE 1950 (A) NORTH ATLANTIC OSCILLATION INDEX, (B) ANOMALIES IN SURFACE AIR TEMPERATURE (C) ARCTIC SEA ICE EXTENT (D) RUNOFF INTO THE ARCTIC OCEAN FROM THE MAJOR SIBERIAN RIVERS (E) GREENLAND SEA DEEP-WATER (GSDW) TEMPERATURE AT 2000M DEPTH

  23. Significant POSITIVE change Precipitation Temperature Significant NEGATIVE change Precipitation Temperature PERCENT OF GLOBAL AREA SAMPLED SHOWING SIGNIFICANT CHANGE IN EXTREME INDICATORS EXTREME EVENTS - 2 TO 4 % INCREASE IN THE FREQUENCY OF HEAVY PRECIPITATION EVENTS IN THE MID- AND HIGH LATITUDES OF THE NORTHERN HEMISPHERE - REDUCTION IN THE FREQUENCY OF EXTREME LOW TEMPERATURES SINCE 1950WITH A SMALLER INCREASE IN THE FREQUENCY OF EXTREME HIGH TEMPERATURES

  24. Focus Natural climate variability and greenhouse warming in the Arctic and sub-Arctic regions. Phenomena • Greenhouse warming - centuries • NAM - Northern hemisphere Annular Mode (NAO/AO oscillations) - decadal • AMO (Atlantic Multi-decadal Oscillations)

  25. Natural variability:the North Atlantic Oscillation dry wet wet dry Positive NAO index Negative NAO index

  26. AMO 0.3 0.3 0.2 0.2 0.1 0.1 0 0 -0.1 -0.1 -0.2 -0.2 -0.3 -0.3 1860 1880 1900 1920 1940 1960 1980 2000 ATLANTIC MULTIDECADAL OSCILLATION (AMO) INDEX 1860 1880 1900 1920 1940 1960 1980 2000 THE HISTORY OF AMO INDEX SHOWS THAT POSITIVE AND NEGATIVE PHASES TYPICALLY LAST FOR 20 TO 40 YEARS. SINCE 1994, THE AMO INDEX HAS BEEN POSITIVE

  27. Conclusions PRONOUNCED CHANGES ON DECADAL AND MULTI-DECADAL TIME SCALES HAVE TAKEN PLACE IN THE ARCTIC OVER THE LAST CENTURY • The global average surface temperature has increased over the 20th century by about 0.57oC, the temperature of the Polar region (60-90oN) has increased by 1.3oC • The increase in temperature in the 20th century has been the largest of any century during the past 1,000 years, the 1990th was the warmest decade • The sea-ice extent over the Northern Hemisphere showed a decrease of about 3% per decade, though MY (perennial) ice declined at a rate of about 9% per decade • We also observe a decrease of snow cover of about 2% per decade and an increase in precipitation and increase in frequency of heavy precipitation events

  28. ANTHROPOGENIC CLIMATE CHANGE WILL PERSIST FOR MANY CENTURIES • Even several centuries after emissions of long-lived greenhouse gases, the amount remaining in the atmosphere is 20 to 30% of the total emitted • Global mean surface temperature will continue to increase and sea level will continue to rise due to thermal expansion for hundreds of years after stabilisation of greenhouse gas concentrations • Ice sheets will continue to react to climate warming and contribute to sea level rise for thousands of years after climate has been stabilised

  29. Possible consequences of less ice in the Arctic • More CO2 uptake in the Arctic Ocean • Sea transport more feasible • Easier to explore and produce oil and gas • Changes in fisheries and biodiversity • Increased freshwater melt reduces deep water formation, with potential reduction of the Gulf Stream into the Nordic Seas

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