Atmospheric feedbacks in North Africa from an irrigated, afforested Sahara

Abstract

Afforestation of the Sahara has been proposed as a climate engineering method to sequester a substantial amount of carbon dioxide, potentially effective to mitigate climate change. Earlier studies predicted changes in the atmospheric circulation system. These atmospheric feedbacks raise questions about the self-sustainability of such an intervention, but have not been investigated in detail. Here, we investigate changes in precipitation and circulation in response to Saharan large-scale afforestation and irrigation with NCAR’s CESM-WACCM Earth system model. Our model results show a Saharan temperature reduction by 6 K and weak precipitation enhancement by 267 mm/year over the Sahara. Only 26% of the evapotranspirated water re-precipitates over the Saharan Desert, considerably large amounts are advected southward to the Sahel zone and enhance the West African monsoon (WAM). Different processes cause circulation and precipitation changes over North Africa. The increase in atmospheric moisture leads to radiative cooling above the Sahara and increased high-level cloud coverage as well as atmospheric warming above the Sahel zone. Both lead to a circulation anomaly with descending air over the Sahara and ascending air over the Sahel zone. Together with changes in the meridional temperature gradient, this results in a southward shift of the inner-tropical front. The strengthening of the Tropical easterly jet and the northward displacement of the African easterly jet is associated with a northward displacement and strengthening of the WAM precipitation. Our results suggest complex atmospheric circulation feedbacks, which reduce the precipitation potential over an afforested Sahara and enhance WAM precipitation.

This is a preview of subscription content, log in to check access.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 10
Fig. 11
Fig. 12
Fig. 13
Fig. 14

Notes

  1. 1.

    http://www.cesm.ucar.edu/models/cesm1.0/clm/CLMcropANDirrigTechDescriptions.pdf.

  2. 2.

    http://trmm.gsfc.nasa.gov.

References

  1. Allaway WG, Mansfield TA (1967) Stomatal responses to changes in carbon dioxide concentration in leaves treated. New Phytol 66:57–63

    Article  Google Scholar 

  2. Ayars JE, Christen EW, Hornbuckle JW (2006) Controlled drainage for improved water management in arid regions irrigated agriculture. Agric Water Manag 86:128–139. doi:10.1016/j.agwat.2006.07.004

    Article  Google Scholar 

  3. Bathiany S, Claussen M, Brovkin V, Raddatz T, Gayler V (2010) Combined biogeophysical and biogeochemical effects of large-scale forest cover changes in the MPI earth system model. Biogeosciences 7:1383–1399. doi:10.5194/bg-7-1383-2010

    Article  Google Scholar 

  4. Betts RA (2011) Climate science: afforestation cools more or less. Nat Geosci 4:504–505. doi:10.1038/ngeo1223

    Article  Google Scholar 

  5. Bowring SPK, Miller LM, Ganzeveld L, Kleidon A (2014) Applying the concept of “energy return on investment” to desert greening of the Sahara/Sahel using a global climate model. Earth Syst Dyn 5:43–53. doi:10.5194/esd-5-43-2014

    Article  Google Scholar 

  6. Broccoli AJ, Dahl KA, Stouffer RJ (2006) Response of the ITCZ to Northern Hemisphere cooling. Geophys Res Lett 33:1–4. doi:10.1029/2005GL024546

    Article  Google Scholar 

  7. Charney JG (1975) Dynamics of deserts and drought in the Sahel. Q J R Meteorol Soc 101:193–202. doi:10.1002/qj.49710142802

    Article  Google Scholar 

  8. Claussen M, Kubatzki C, Brovkin V, Ganopolski A, Hoelzmann P, Pachur H-J (1999) Simulation of an abrupt change in Saharan vegetation in the mid-Holocene. Geophys Res Lett 26:2037–2040. doi:10.1029/1999GL900494

    Article  Google Scholar 

  9. Cook KH (1999) Generation of the African easterly jet and its role in determining West African precipitation. J Clim 12:1165–1184. doi:10.1175/1520-0442(1999)012<1165:GOTAEJ>2.0.CO;2

    Google Scholar 

  10. Cook KH, Vizy EK (2006) Coupled model simulations of the West African monsoon system: twentieth- and twenty-first-Century simulations. J Clim 19:3681–3703. doi:10.1175/JCLI3814.1

    Article  Google Scholar 

  11. Cook K, Meehl G a, Arblaster JM (2012) Monsoon Regime and processes in CCSM4. Part II: African and American monsoon systems. J Clim 25:2609–2621. doi:10.1175/JCLI-D-11-00185.1

    Article  Google Scholar 

  12. Danabasoglu G, Bates SC, Briegleb BP, Jayne SR, Jochum M, Large WG, Peacock S, Yeager SG (2012) The CCSM4 ocean component. J Clim 25:1361–1389. doi:10.1175/JCLI-D-11-00091.1

    Article  Google Scholar 

  13. DeMott PJ, Sassen K, Poellot MR, Baumgardner D, Rogers DC, Brooks SD, Prenni AJ, Kreidenweis SM (2003) African dust aerosols as atmospheric ice nuclei. Geophys Res Lett 30:26–29. doi:10.1029/2003GL017410

    Article  Google Scholar 

  14. Devaraju N, Bala G, Modak A (2015) Effects of large-scale deforestation on precipitation in the monsoon regions: remote versus local effects. Proc Natl Acad Sci 112:201423439. doi:10.1073/pnas.1423439112

    Article  Google Scholar 

  15. Diongue A, Lafore J-P, Redelsperger J-L, Roca R (2002) Numerical study of a Sahelian synoptic weather system: Initiation and mature stages of convection and its interactions with the large-scale dynamics. Q J R Meteorol Soc 128:1899–1927. doi:10.1256/003590002320603467

    Article  Google Scholar 

  16. Garcia RR, Marsh DR, Kinnison DE, Boville BA, Sassi F (2007) Simulation of secular trends in the middle atmosphere, 1950–2003. J Geophys Res Atmos 112:1–23. doi:10.1029/2006JD007485

    Google Scholar 

  17. Grist JP, Nicholson SE (2001) A study of the dynamic factors influencing the rainfall variability in the West African Sahel. J Clim 14:1337–1359. doi:10.1175/1520-0442(2001)014<1337:ASOTDF>2.0.CO;2

    Article  Google Scholar 

  18. Harlaß J, Latif M, Park W (2015) Improving climate model simulation of tropical Atlantic sea surface temperature: The importance of enhanced vertical atmosphere model resolution. doi:10.1002/2015GL063310.Received

  19. Harrison SP, Bartlein PJ, Izumi K, Li G, Annan J, Hargreaves J, Braconnot P, Kageyama M (2015) Evaluation of CMIP5 palaeo-simulations to improve climate projections. Nat Clim Chang 5:735–743. doi:10.1038/nclimate2649

    Article  Google Scholar 

  20. Holland MM, Bailey D a., Briegleb BP, Light B, Hunke E (2012) Improved sea ice shortwave radiation physics in CCSM4: the impact of melt ponds and aerosols on Arctic Sea Ice*. J Clim 25:1413–1430. doi:10.1175/JCLI-D-11-00078.1

    Article  Google Scholar 

  21. Huffman GJ, Bolvin DT, Nelkin EJ, Wolff DB, Adler RF, Gu G, Hong Y, Bowman KP, Stocker EF (2007) The TRMM multisatellite precipitation analysis (TMPA): quasi-global, multiyear, combined-sensor precipitation estimates at fine scales. J Hydrometeorol 8:38–55. doi:10.1175/JHM560.1

    Article  Google Scholar 

  22. Irizarry-Ortiz MM, Wang G, Eltahir EAB (2003) Role of the biosphere in the mid-Holocene climate of West Africa. J Geophys Res D Atmos 108:ACL 5-1–ACL 5-15. Artn 4042. doi:10.1029/2001jd000989

    Google Scholar 

  23. Kafando P, Chane-Ming F, Petitdidier M (2015) Stratospheric variability of wave activity and parameters in equatorial coastal and tropical sites during the West African monsoon. Clim Dyn. doi:10.1007/s00382-015-2764-1

  24. Keller DP, Feng EY, Oschlies A (2014) Potential climate engineering effectiveness and side effects during a high carbon dioxide-emission scenario. Nat Commun 5:3304. doi:10.1038/ncomms4304

    Google Scholar 

  25. Kojima T, Kakubari Y, Komiyama H (1995) Significance of afforestation of desert and its evaluation as a countermeasure against carbon dioxide problem. Energy Convers Manag 36:923–926. doi:10.1016/0196-8904(95)00154-6

    Article  Google Scholar 

  26. Kraus EB (1977) Subtropical droughts and cross-equatorial energy transports. Mon Weather Rev 105:1009–1018

    Article  Google Scholar 

  27. Lawrence DM, Oleson KW, Flanner MG, Fletcher CG, Lawrence PJ, Levis S, Swenson SC, Bonan GB (2012) The CCSM4 land simulation, 1850–2005: assessment of surface climate and new capabilities. J Clim 25:2240–2260. doi:10.1175/JCLI-D-11-00103.1

    Article  Google Scholar 

  28. Leng G, Huang M, Tang Q, Sacks WJ, Lei H, Leung LR (2013) Modeling the effects of irrigation on land surface fluxes and states over the conterminous United States: sensitivity to input data and model parameters. J Geophys Res Atmos 118:9789–9803. doi:10.1002/jgrd.50792

    Article  Google Scholar 

  29. Liou KN (2002) An introduction of atmospheric radiation, 2nd edn. Academic Press, Chap. 8

  30. Marsh DR, Mills MJ, Kinnison DE, Lamarque JF, Calvo N, Polvani LM (2013) Climate change from 1850 to 2005 simulated in CESM1(WACCM). J Clim 26:7372–7391. doi:10.1175/JCLI-D-12-00558.1

    Article  Google Scholar 

  31. Nicholson SE (2009) A revised picture of the structure of the “monsoon” and land ITCZ over West Africa. Clim Dyn 32:1155–1171. doi:10.1007/s00382-008-0514-3

    Article  Google Scholar 

  32. Nicholson SE (2013) The West African Sahel: a review of recent studies on the rainfall regime and its interannual variability. ISRN Meteorol 2013:32. doi:10.1155/2013/453521

  33. Nicholson SE, Grist JP (2001) A conceptual model for understanding rainfall variability in the West African Sahel on interannual and interdecadal timescales. Int J Climatol 21:1733–1757. doi:10.1002/joc.648

    Article  Google Scholar 

  34. Oleson KW, Lawrence DM, Gordon B, Flanner MG, Kluzek E, Peter LJ, Levis S, Swenson SC, Thornton PE (2010) Technical description of version 4.0 of the community land model (CLM). NCAR/TN-478 + STR NCAR Tech Note 266

  35. Ornstein L, Aleinov I, Rind D (2009) Irrigated afforestation of the Sahara and Australian Outback to end global warming. Clim Change 97:409–437. doi:10.1007/s10584-009-9626-y

    Article  Google Scholar 

  36. Ozawa H, Okabayashi T, Komiyama H, Kaya Y (1995) Research of arid land afforestation technologies for carbon dioxide fixation. Energy Convers Manag 36:911–914

    Article  Google Scholar 

  37. Parajuli SP, Yang Z-L, Lawrence DM (2016) Diagnostic evaluation of the Community Earth System Model in simulating mineral dust emission with insight into large-scale dust storm mobilization in the Middle East and North Africa (MENA). Aeolian Res 21:21–35. doi:10.1016/j.aeolia.2016.02.002

    Article  Google Scholar 

  38. Park J-Y, Bader J, Matei D (2015) Northern-hemispheric differential warming is the key to understanding the discrepancies in the projected Sahel rainfall. Nat Commun 6:5985. doi:10.1038/ncomms6985

    Article  Google Scholar 

  39. Park J, Bader J, Matei D (2016) Anthropogenic Mediterranean warming essential driver for present and future Sahel rainfall. Nat Clim Chang 6:1–6. doi:10.1038/nclimate3065

    Article  Google Scholar 

  40. Patricola CM, Cook KH (2008) Atmosphere/vegetation feedbacks: A mechanism for abrupt climate change over northern Africa. J Geophys Res 113:D18102. doi:10.1029/2007JD009608

    Article  Google Scholar 

  41. Pausata FSR, Messori G, Zhang Q (2016) Impacts of dust reduction on the northward expansion of the African monsoon during the Green Sahara period. Earth Planet Sci Lett 434:298–307. doi:10.1016/j.epsl.2015.11.049

    Article  Google Scholar 

  42. Prentice IC, Jolly D (2000) Mid-Holocene and glacial-maximum vegetation geography of the northern continents and Africa. J Biogeogr 27:507–519. doi:10.1046/j.1365-2699.2000.00425.x

    Article  Google Scholar 

  43. Rachmayani R, Prange M, Schulz M (2015) North African vegetation-precipitation feedback in early and mid-Holocene climate simulations with CCSM3-DGVM. Clim Past 11:175–185. doi:10.5194/cp-11-175-2015

    Article  Google Scholar 

  44. Richter I, Xie SP (2008) On the origin of equatorial Atlantic biases in coupled general circulation models. Clim Dyn 31:587–598. doi:10.1007/s00382-008-0364-z

    Article  Google Scholar 

  45. Richter JH, Sassi F, Garcia RR (2010) Toward a physically based gravity wave source parameterization in a general circulation model. J Atmos Sci 67:136–156. doi:10.1175/2009JAS3112.1

    Article  Google Scholar 

  46. Rienecker MM, Suarez MJ, Gelaro R, Todling R, Bacmeister J, Liu E, Bosilovich MG, Schubert SD, Takacs L, Kim GK, Bloom S, Chen J, Collins D, Conaty A, Da Silva A, Gu W, Joiner J, Koster RD, Lucchesi R, Molod A, Owens T, Pawson S, Pegion P, Redder CR, Reichle R, Robertson FR, Ruddick AG, Sienkiewicz M, Woollen J (2011) MERRA: NASA’s modern-era retrospective analysis for research and applications. J Clim 24:3624–3648. doi:10.1175/JCLI-D-11-00015.1

    Article  Google Scholar 

  47. Shepherd JG (2012) Geoengineering the climate: an overview and update. Philos Trans R Soc A Math Phys Eng Sci 370:4166–4175. doi:10.1098/rsta.2012.0186

    Article  Google Scholar 

  48. Smith LJ, Torn MS (2013) Ecological limits to terrestrial biological carbon dioxide removal. Clim Change 118:89–103. doi:10.1007/s10584-012-0682-3

    Article  Google Scholar 

  49. Smith P, Davis SJ, Creutzig F, Fuss S, Minx J, Gabrielle B, Kato E, Jackson RB, Cowie A, Kriegler E, van Vuuren DP, Rogelj J, Ciais P, Milne J, Canadell JG, McCollum D, Peters G, Andrew R, Krey V, Shrestha G, Friedlingstein P, Gasser T, Grübler A, Heidug WK, Jonas M, Jones CD, Kraxner F, Littleton E, Lowe J, Moreira JR, Nakicenovic N, Obersteiner M, Patwardhan A, Rogner M, Rubin E, Sharifi A, Torvanger A, Yamagata Y, Edmonds J, Yongsung C (2015) Biophysical and economic limits to negative CO2 emissions. Nat Clim Chang 6:42–50. doi:10.1038/nclimate2870

    Article  Google Scholar 

  50. Swann ALS, Fung IY, Chiang JCH (2012) Mid-latitude afforestation shifts general circulation and tropical precipitation. Proc Natl Acad Sci USA 109:712–716. doi:10.1073/pnas.1116706108

    Article  Google Scholar 

  51. Swann ALS, Fung IY, Liu Y, Chiang JCH (2014) Remote Vegetation Feedbacks and the Mid-Holocene Green Sahara. J Clim 27:4857–4870. doi:10.1175/JCLI-D-13-00690.1

    Article  Google Scholar 

  52. Thiéblemont R, Matthes K, Omrani N-E, Kodera K, Hansen F (2015) Solar forcing synchronizes decadal North Atlantic climate variability. Nat Commun 6:8268. doi:10.1038/ncomms9268

    Article  Google Scholar 

  53. Thorncroft CD, Nguyen H, Zhang C, Peyrille P (2011) Annual cycle of the West African monsoon: Regional circulations and associated water vapour transport. Q J R Meteorol Soc 137:129–147. doi:10.1002/qj.728

    Article  Google Scholar 

  54. Tierney JE, Pausata FSR, deMenocal PB (2017) Rainfall regimes of the Green Sahara. Sci Adv 3:1–9. doi:10.1126/sciadv.1601503

    Article  Google Scholar 

  55. Wang Y, Notaro M, Liu Z, Gallimore R, Levis S, Kutzbach JE (2008) Detecting vegetation-precipitation feedbacks in mid-Holocene North Africa from two climate models. 59–67. doi:10.5194/cp-4-59-2008

  56. Wu M-LC, Reale O, Schubert SD, Suarez MJ, Koster RD, Pegion PJ (2009) African easterly jet: structure and maintenance. J Clim 22:4459–4480. doi:10.1175/2009JCLI2584.1

    Article  Google Scholar 

  57. Yu K, D’Odorico P, Bhattachan A, Okin GS, Evan AT (2015) Dust-rainfall feedback in West African Sahel. Geophys Res Lett 42:7563–7571. doi:10.1002/2015GL065533

    Article  Google Scholar 

Download references

Acknowledgements

This work is a contribution to the DFG-funded Priority Program SPP 1689 and was partly performed within the Helmholtz-University Young Investigators Group NATHAN, funded by the Helmholtz-Association and GEOMAR, the Helmholtz Centre for Ocean Research Kiel. The CESM-WACCM simulations have been performed at the Deutsche Klimarechenzentrum (DKRZ) in Hamburg, Germany. We thank two anonymous reviewers for their helpful comments.

Author information

Affiliations

Authors

Corresponding author

Correspondence to Tronje Peer Kemena.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Kemena, T.P., Matthes, K., Martin, T. et al. Atmospheric feedbacks in North Africa from an irrigated, afforested Sahara. Clim Dyn 50, 4561–4581 (2018). https://doi.org/10.1007/s00382-017-3890-8

Download citation

Keywords

  • Afforestation
  • Climate engineering
  • Circulation
  • Irrigation
  • West African monsoon