Major Feedbacks originating from Northern Eurasia that are of global change concern

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1 Major Feedbacks originating from Northern Eurasia that are of global change concern Guy P. Brasseur National Center for Atmospheric Research Boulder, CO

2 Regions of Strong Influences on the Global Earth System Schellnhuber

3 Vulnerability of the Carbon Cycle in the 21 st Century Hot Spots of the Carbon-Climate-Human System Land Permafrost HL Peatlands Tr Peatlands Veg.-Fire/LUC Oceans CH 4 Hydrates Biological Pump Solubility Pump GCP 2005

4 Recent Historical Climate Change

5 Global Temperature Trends: 2005 Summation

6 Understanding and Attributing Climate Change Anthropogenic warming is likely significant averaged over each of the inhabited continents Observed Expected for all forcings Natural forcing only

7 Land precipitation is changing significantly over broad areas Increases Decreases Smoothed annual anomalies for precipitation (%) over land from 1900 to 2005; other regions are dominated by variability.

8 An ice free Arctic? City Lights from Space

9 Changes in spring snow cover

10 Widespread delays in lake and river freeze dates, while breakup is earlier, i.e., winter is shorter [Magnuson, Science, 2000]

11 Glaciers and frozen ground are receding Increased Glacier retreat since the early 1990s Area of seasonally frozen ground in NH has decreased by 7% from 1901 to 2002

12 Models of Future Climate Change

13 Change in Temperature Frontier Research Center, Japan

14 A1B is a typical business as usual ( ) scenario: Global mean warming 2.8 o C; Much of land area warms by ~3.5 o C Arctic warms by ~7 o C; would be less for less emission

15 Future Global Warming

16 Figure TS-30 Updated: 27 March 2007

17

18 OCEAN / ICE IPCC Scenario with ECHAM5/MPI-OM

19 Better Representation of the Ice Sheet Abrupt Transitions in the Summer Sea Ice (NCAR Model) Observations Simulated 5-year running mean Abrupt transition Gradual forcing results in abrupt Sept ice decrease Extent decreases from 80 to 20% coverage in 10 years. Relevant factors: Ice thinning Arctic heat transport Albedo feedback Winter maximum shows smaller, gradual decreases

20 From Climate Models to Earth System Models

21 The Conceptual Framework

22 The Conceptual Framework Climate change Air pollution Climate change Air pollution

23 Earth System Framework Socio-economic Models Climate change Air pollution Climate change Air pollution Dynamic Global Vegetation Models Biophysical and Biogeochemical Models General Circulation Models Regional Atmospheric Models Chemical Transport Models Terrestrial Hydrology Models Ocean General Circulation Models Ocean Biogeochemical Models

24 Introducing Life into Earth System Models To develop a modelling system for the biosphere, in its broadest terms, which can represent in functional form how it is influenced by, and itself influences, human activities and the climate system To establish a modelling framework that allows such a modelling system to be fully coupled with the physical system.

25 Challenges for the Future Based on P. Cox, 2004 CLIMATE Direct and Indirect Effects / Feedbacks on natural sources Greenhouse Effect Human Emissions AEROSOLS Heat island effect GREENHOUSE GASES Oxidants: OH, H 2 O 2 HO 2,O 3 Fires: soot Mineral dust CH 4, O 3, N 2 O, CFC CO 2 Human Emissions (Gas-phase) CHEMISTRY N deposition 0 3, UV radiation Biogenic Emissions:CH 4,DMS,VOC s Dry deposition: stomatal conductance ECOSYSTEMS Human Emissions LAND WATER / CITIES Damming / Irrigation / Emission of heat Land-use Change, Fires The future: a full treatment of climate-chemistry-ecosystem-land surface feedbacks

26 Feedbacks between the Euroasian continent and the global Earth system The water cycle, precipitation, run-off Surface moisture, energy and vegetation Snow cover/melt The cryosphere Permafrost and methane release Vegetation and the carbon cycle Dust and other aerosols Fires Biogenic emissions and air quality Etc.

27 Effects of vegetation on climate via surface moisture budget Water vapour from oceans Rain Some rain water recycled Evaporation & transpiration affect sensible and latent heat fluxes Drainage to rivers Extraction of soil water by roots

28 Effect of land cover change on climate More reflection of solar radiation by open land More absorption of solar radiation by forest

29 CO 2 rise, climate change and the hydrological cycle Precipitation Surface evaporation Transpiration Affected by climate change Also affected directly by changing CO 2 concentration ( Physiological Forcing ) Surface runoff Infiltration Subsurface runoff

30 Cloud processes Organic aerosol processes Biological particles and VOC emissions CO2 Carbon Cycle Photo-oxidant processes Latent and H2O sensible heat NO/NH3 emission Water & Energy Cycles Precipitation and solar radiation Disturbances: Insect outbreaks Gas/oil production NOy NH3 Nitrogen Cycle Ozone and N deposition Agriculture

31 Net Primary Productivity

32 Carbon Climate Interactions

33 Pre-industrial carbon fluxes (positive upward) January July uptake release [gc/day m 2 ]

34 Atmospheric CO2 Difference Atmospheric CO2 Feedback C4MIP (IGBP/AIMES)

35 Difference in carbon uptake between experiments (with minus without carbon cycle - climate feedback) 2100 positive feedback negative feedback [kgc / m 2 ]

36 Summary Carbon-climate feedback is positive: + 83 ppm in 2100 IPSL (Friedlingstein et al., 2001): + 75 ppm Hadley Centre (Cox et al., 2000): ppm This is caused, predominantly, by reduced NPP at low latitudes (GPP is unchanged but autotrophic respiration is enhanced) At middle and high latitudes the carbon uptake is larger in the climate change experiment, because the increase in NPP is larger than the decrease in soil carbon uptake (heterotrophic respiration is enhanced in the warmer climate) The carbon uptake by the ocean is almost identical in both experiments (exception: reduced uptake in the North Atlantic due to a weakening of the THC in the warmer climate)

37 Challenges for the Future Better quantify the different processes affecting the global carbon cycle. Study biogeochemistry of the land-atmosphere interface, and couple it to the hydrological cycle, human perturbations, and climate changes Couple the carbon cycle with other biogeochemical cycles (e.g., nitrogen). Consider a potential positive methane climate feedback

38 From 1860 to Present Grain Production Meat Production Energy Production

39 Changes in nutrient loading Humans have already doubled the flow of reactive nitrogen on the continents, and some projections suggest that this may increase by roughly a further two thirds by 2050 Estimated Total Reactive Nitrogen Deposition from the Atmosphere

40 The Global Nitrogen Budget in 1860 and mid-1990s, TgN/yr NO y N NH x mid-1990s NO y N NH x N 2 + 3H NH 3 Galloway et al., 2002b

41 Dynamic Global Nitrogen Scheme Natural N fix N Deposition Soil Inorganic N Pool Litter Fall Litter N Pool Mineralization Plant N Pool NH 3 Volatilizaiton NH 3 Up take Nitrification N 2 O NO N 2 N 2 O Denitrification NO NH 4 + NO 3 - NO 2 - Mineralization Soil Organic N Pool Mineralization Assimilation Leaching XuRi et al., MPI, 2005

42 Frankenberg et al., Science, 2005 (Science Express 17th March) CH 4 from space in August through Nov From J. Burrows, Univ. of Bremen

43 Methane allocation and transport O 2 E M I S S I O N aerobic horizon micro-aerobic horizon root oxidation vascular transport root exudation o x i d a t i o n diffusion ebullition water table level anaerobic horizon acetate, CO 2, H 2 dissolved CH 4 m e t h a n o - g e n e s i s entrapped gas bubbles gaseous CH 4 decomposition of dead organic matter

44 Aerosols and Climate

45 Springtime aerosols over Eastern Asia, 2007 March 30 March 31 March 31 marked opening ceremonies for the first Green China Day established to increase awareness of the need for environmental protection. However, the ceremony in Beijing saw an unwelcome guest: Gobi Desert dust. Roughly 2,000 kilometers south of the capital city, air quality also suffered, in this case from fires in Southeast Asia.

46 Global Aerosol Distribution From: Ph. Stier; Animation: M. Boettinger, DKRZ

47 Climate Response to Potential Improvement in Air Quality (K) In blue: GHG unchanged after year 2000 (commitment experiment). (%) In Red: GHG unchanged and anthropogenic sulfate aerosols removed after year 2000 (sensitivity experiment).

48 Changes in the Shortwave radiative energy (Wm -2 ) in response to sulfate removal (30 year average) Removal of aerosols leads to anomalous radiative heating in industrialized regions. Cloud radiative forcing is positive in a warmer and cleaner tropical atmosphere where clouds are less abundant. Cloud reflection at high latitudes is increased due to enhanced cloud formation in areas where sea ice is melting.

49 Response in Temperature and Precipitation (30 year average) Temperature increase larger than 1K over the continents, larger than 4K in the Arctic. Temperature and precipitation changes bear some resemblance with greenhouse warming experiments A significant increase in precipitation is found in Eastern Pacific, suggesting an El-Nino like change in the mean climate state.

50 Challenges for the Future Address fundamental uncertainties in our understanding of aerosol microphysics, chemical composition of aerosols, aerosol-cloud interactions, indirect climate effects, etc. Assess in particular the role of organic aerosols. Develop appropriate field campaigns, laboratory experiments, and physical models to provide the basic knowledge required to study the aerosol climate interactions. Investigate the role of aerosols in the earth system: impact on the biosphere, on the ocean, the carbon cycle, etc.

51 Research Challenges for Tomorrow

52 Global Change Interactions Atmospheric Composition Climate and Sea Level Atmospheric Chemistry Climate Ocean Carbon Cycle Ocean - temperature - sea level Human Activities Ecosystems Energy System Other Human Systems Terrestrial Carbon Cycle Unmanaged Ecosystem Agriculture, Livestock and Forestry Coastal System Crops and Forestry Hydrology

53 Emissions Climate Dynamics ImpactsConservation Radiative Forcing Mitigation Geoengineering Impacts Adaptation Atmospheric Composition Mitigation Emissions Natural & Managed Ecoystems Costs & Benefits Risks Disaster Management Demand Compensation Strategic Decision Making Perceptions Human Behaviour & Well-Being Impacts Risks Education Demand Investment Costs & Benefits Adaptation Industrial Metabolism From: H.-J. Schellnhuber

54 Hot Topics for Future Research Interfaces between components of the Earth System. Global water and biogeochemical cycles Hot spots and teleconnections in the Earth System Integrated interdisciplinary regional studies (inc. social systems) Integration of scales: from nano-processes to global evolution. Research towards operational systems for monitoring, and predicting the evolution of the Earth System on different timescales (data assimilation).

55 Thank You