Land cover effect on climate Martin Claussen Max Planck Institut for Meteorology KlimaCampus Hamburg CITES 2009
Land cover and climate dynamics Martin Claussen Max Planck Institut for Meteorology KlimaCampus Hamburg CITES 2009
Alexander von Humboldt, Kosmos (1845) The term climate refers to a specific property of the atmosphere which however depends on the feedback with the ocean and the land surface
today Mid Holocene, 6000 years ago Example: Interglacial Glacial Cycles Last Glacial l Maximum, 21000 years ago Prentice, Webb et al., 2000
Outline Biogeophysical perspective (energy fluxes) - Holocene boreal warming - North African wet phase(s) Biogeochemical perspective (carbon cycle)
Orbital forcing of glacial - interglacial climate change Change in solar energy flux [W/m 2 ], (%) tude latit July January time --> latitude time --> Berger, 1978
The mid-holocene winter riddle? T K Difference in temperature of the coldest month some 6000 years ago Cheddadi et al., 1997
Boreal feedbacks and synergies Change in near-surface winter mean temperature full model atmosphere-only model ECHAM6/MPIOM vegetation-only model ocean-only model Otto et al., 2009-2 -1 T[K] +1 +2
Boreal feedbacks and synergies Change in near-surface winter mean temperature full model atmosphere-only model ECHAM6/MPIOM Change in tree fraction vegetation-only model ocean-only model -0.4-0.2 [%] 0.2 0.4 Otto et al., 2009-2 -1 T[K] +1 +2
Boreal feedbacks and synergies Change in near-surface winter mean temperature full model atmosphere-only model ECHAM6/MPIOM Change in tree fraction vegetation-atm. model ocean-only model -0.4-0.2 [%] 0.2 0.4 Otto et al., 2009-2 -1 T[K] +1 +2
Boreal feedbacks and synergies
Boreal feedbacks and synergies Change in near-surface winter mean temperature full model atmosphere-only model ECHAM6/MPIOM Change in tree fraction vegetation-atm. model ocean-only model -0.4-0.2 [%] 0.2 0.4 Otto et al., 2009-2 -1 T[K] +1 +2
Boreal feedbacks and synergies Change in near-surface winter mean temperature full model atmosphere-only model ECHAM6/MPIOM Change in tree fraction vegetation-atm. model ocean-only model -0.4-0.2 [%] 0.2 0.4 Change in sea ice Otto et al., 2009-2 -1 T[K] +1 +2-0.65-0.35-0.05 [%]
Boreal feedbacks and synergies Change in near-surface winter mean temperature full model atmosphere-only model ECHAM6/MPIOM Change in tree fraction vegetation-atm. model ocean-atm. model -0.4-0.2 [%] 0.2 0.4 Change in sea ice Otto et al., 2009-2 -1 T[K] +1 +2-0.65-0.35-0.05 [%]
Boreal feedbacks and synergies Change in near-surface winter mean temperature full model atmosphere-only model ECHAM6/MPIOM Change in tree fraction vegetation-atm. model synergy ocean-atm. model -0.4-0.2 [%] 0.2 0.4 Change in sea ice Otto et al., 2009-2 -1 T[K] +1 +2-0.65-0.35-0.05 [%]
Boreal feedbacks and synergies Contributions to temperature change north of 40 o N over land Otto et al., 2009
Boreal feedbacks and synergies Contributions to temperature change north of 40 o N over land Claussen, 2009; Otto et al. 2009
Boreal feedbacks and synergies at Last Glacial Maximum Contribution to Glacial Cooling Vegetation ~0.7K CO 2 ~1.5K 2% 9% feedbacks and factors 2% 2% I C CI Iveg 28% 57% Cveg Ice Sheets ~3K Civeg CLIMBER-2.3 Jahn et al., 2005
Transient Feedbacks and Climatic Precession transient ice sheets and CO 2 prescribed AOV_IC AO_IC A AV AO AOV ice sheets and CO 2 fixed at 200 ky BP Claussen et al., 2006
Outline Biogeophysical perspective (energy fluxes) - Holocene boreal warming - North African wet phase(s) Biogeochemical perspective (carbon cycle)
Orbital forcing monsoon systems Change in surface temperature Differences: 6 ka - today Change in surface pressure Latitude Longitude Longitude Kubatzki, 2000
Precipitation changes [mm/y] over WestAfrica 0 200 500 900 0 PMIP Joussaume et al., 1999-200 25N 20N 15N 10N 5N Vegetation as indicator of climate S. Lorenz, pers.com.
Precipitation changes [mm/y] over WestAfrica 0 500 90 AOV Braconnot et al., 1999 AV AO 0 200 A -200 25N 20N 15N 10N 5N Ganopolski et al., 1998 Claussen & Gayler, 1997 Interactive vegetation
North African monsoon / Saharan dynamics Charney s (1975) mechanism Radiative balance (W/m 2 ) at the top of the atmosphere Charney, 1975
various simulations / data of the green Sahara Claussen and Gayler, 1997 Doherty et al., 2000 Schurgers et al., 2007 Liu et al., 2007 Hoelzmann et al., 1999 Prentice et al., 2000
1.0 0.8 0.6 0.4 0.2 0.0 10 1.0 0.8 0.6 04 0.4 0.2 0.0 Age (ka BP) 0 10 20 30 40 50 60 70 80 90 100 110 120 a b c MIS 2 MIS 3 MIS 4 MIS 5 0 10 20 30 40 50 60 70 80 90 100 110 120 Age (ka BP) 10 1.0 0.8 0.6 04 0.4 0.2 0.0 Tjallingii et al., 2008
Multiple equilibrium solutions!? today Claussen, 1997, 1998; 6000 y BP Claussen and Gayler, 1997; LGM Kubatzki and Claussen, 1998
various simulations / data of the Saharan dynamics t Gras ss Gras ss Gras ss Vegetati ion 14 C date es Dus 9000 7000 5000 3000 1000 years ago CLIMBER-2 2(Sahara) Claussen et al., 1999 ECBILT-CLIO-VECODE (Western Sahara) Renssen et al., 2003 FOAM-LPJ (Eastern Sahara) Liu et al., 2007 Atlantic ti marine sediments demenocal et al., 2000 C14-dates (Eastern Sahara) Pachur, 1999 Lake Yoa (NE of Lake Tchad) Kroepelin et al., 2008
Outline Biogeophysical perspective (energy fluxes) - Holocene boreal warming - North African wet phase(s) Biogeochemical perspective (carbon cycle)
A thought experiment Potential forest cover in ECHAM6/MPIOM Brovkin et al., 2009
Temperature changes tropical deforestation tropical afforestation boreal deforestation boreal afforestation Bathiany et al., in prep.
Results from CLIMBER-2.1 ECHAM6/MPIOM Claussen et al., 2001; Bathiany et al., in prep.
Mid Holocene, 6000 years ago Little change in tropical forest fraction between glacial and interglacial Boreal forest zones regressed equatorward and compressed to 1/3 during glacials Terrestrial carbon loss (glacial vs. interglacial) +20 25 ppmv in the atmosphere 0.2 0.4 K warming versus 0.6 0.7 K biogeophysical cooling Last Glacial Maximum, 21000 years ago Claussen, 2009; Prentice, Webb et al., 2000
Land Cover and Climate Dynamics Vegetation dynamics is an important component in the climate system. Presumably, the terrestrial biosphere amplifies external climate forcing: - Saharan dynamics - Holocene wintertime warming (?) - Glacial cooling (?) At high latitudes (with vegetation-snow albedo feedback) biogeophysical feedback seems to dominate biogeochemical feedback, in the tropics biogeochemical feedback seems to win. Thank you very much for attention! Claussen, Climate of the Past, 2009
Land Cover and Climate Dynamics Vegetation dynamics is an important component in the climate system. Presumably, the terrestrial biosphere amplifies external climate forcing. ( Anthropogenic land cover change climate )? Effect of permafrost and soil carbon Thanks due to Victor Brovkin, Christian Reick, Thank you very much for your attention!
Bonus tracks
Boreal feedbacks and synergies Astronomical Calendar Present Calendar Otto et al., 2009
Boreal feedbacks and synergies Otto et al., 2009b
Biogeochemical perspective - a thought experiment Deforestation of boreal forest (50 60 N) biogeophysical effect biogeochemical effect both effects Deforestation of tropical forests (0 10 S) biogeophysical effect biogeochemical effect both effects