Carbon Consequences of China's Land Cover Changes -- Climate or Human Responsible?

Transcription

1 Carbon Consequences of China's Land Cover Changes -- Climate or Human Responsible? Jiaguo Qi, Director Center for Global Change and Earth Observations Department of Geography Michigan State University Team: Dr. Jianjun Ge (Oklahoma State University); Dr. Haiyan Wei (USDA-ARS, Tucson, AZ); Dr. Phil Heilman (USDA-ARS, Tucson, AZ); Mr. Feng Zhang (Lanzhou University); Nathan Moore (MSU and ZJU)

2 Through my research and international activities, I learned that the environmental issues in Central Asia need to be addressed urgently!

3 Why Central Asia? R U S S I A K A Z A K H S T A N M O N G O L I A No data C H I N A Population Changes in Central Asia (50s-80s)(Unit:1000)

4 westerlies Sensitive to climate change Arctic-North Atlantic Low Siberia- Mongoli an High (Aleutian Low) North Pacif Low? Indian Low Subtropical High Indian Monsoon Asian Monsoon

5 (MODIS true Color) , (MODIS false color) (MODIS true color) (MODIS true color) (MODIS true color)

6 Agricultural Intensification

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8 Desertification Salinization Degradation

9 The National Research Council on March 12 released a report, Informing Decisions in a Changing Climate, that concludes we are unprepared, both conceptually and practically for climate change and that it is no longer valid to base decisions on the assumption of continued climatic conditions of the past.

10 Science Questions To what extent have human activities affected regional climate change? To what extent has the climate change affected ecosystems? Human System Ecosystems Climate System How to discern the human impacts on China s ecosystem dynamics from climate impacts?

11 Approaches

12 Approach 1: Observational and Statistical Modeling Remote sensing temporal change GIMMS ( ) and MODIS ( ) time series In phenological and carbon/biomass Time series analysis with TIMESAT Calculate the biomass Correlations analysis biomass climate Correlation coefficients: percentage of explanation Examine residuals: percentage of explanation?

13 SI

14 Approach 2: System Modeling Climate Downscaling (RAMS) Environmental Consequences (N2O, CO2, CH4 ) Basic R S & GIS Layers soil, property, Practice Watersheds Ecosystem Models (DNDC, TMDL) Land Use/Cover Change Socioeconomic Scenarios: Household Dynamics and Management Practices BMPs

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16 Climate data 738 meteorological stations across China

17 To answer the question: How to discern climate impact from human disturbance?

18 Example map of Small Integral (SI) The SI over the growing season in 1982 across China

19 Slope of linear temporal trend of small integral across China from 1982 to 2006 (p<=0.05)

20 Correlation between SI and and climate factors Correlation coefficient between SI and P July

21 Correlation between SI and and climate factors Correlation coefficient between SI and T July

22 Taking the 8 counties as an example:

23 Results, residual trend # County Relationship between small integral and selected climate factors linear temporal trend of residual Equation r 2 Equation r 2 1 Changji Sl = P July T June T July 0.59 y=15.96x Dengkou SI = P July T April T June 0.67 y = 6.96x Qingshuihe SI = P July T May T July 0.39 y = 30.06x Aohan SI = P June T Feb T July 0.34 y = 29.2x Nantong SI = P July T April T July 0.52 y = x Qianjiang SI = T Feb T April T June 0.42 y = x Guangning SI = P July T April T July 0.38 y = x Mabian SI = P July T Feb T April 0.44 y = x

24 Linear temporal trend of residual Changji 2. Dengkou 3. Qingshuihe 4. Aohan Residual Year

25 Linear temporal trend of residual Nantong 6. Qianjiang 7. Guangning 8. Mabian 500 Residual Year

26 To answer the question: How has the climate change impacted the carbon sequestration of China grassland?

27 Grassland above ground carbon change trend from 2000 to 2007

28 Grassland soil carbon storage change trend from 2000 to 2007

29 fan below ground vegetation carbon density(kgc/ha) fan below ground vegetation carbon storage(pgc) y = x R 2 = Estimated below ground vegetation carbon density(kgc/ha) y = x R 2 = Estimated below ground vegetation carbon storage(pgc) C density (PgC/ha) Below ground carbon results compare with Fan s results C storage (PgC)

30 Ni forage carbon density (KgC/ha) y = x R 2 = Estimated above ground carbon density (KgC/ha) C density (PgC/ha) Above ground carbon result compare with Ni s results 0.03 Ni forage carbon storage(pgc) y = 0.323x R 2 = C storage (PgC) Estimated above ground carbon storage(pgc)

31 Conclusions Remote sensing, long term monitoring data can be very useful to study ecosystem changes Statistical approaches are useful in understanding the drivers of changes (discern climate cause from human impacts) Biogeochemical models (DNDC) incorporate human and climate into a system to quantitatively assess ecosystem responses to both climate and human drivers More research is needed to investigate the change patterns and their linkages to specific policy implementations (on going) On-going research focuses on fine resolution MODIS type data for other land cover types

32 Acknowledgment NASA and NSF funding Chinese MOST funding through CAS