Climate Dynamics

, Volume 37, Issue 5–6, pp 915–931

# Albedo enhancement of marine clouds to counteract global warming: impacts on the hydrological cycle

• G. Bala
• Ken Caldeira
• Rama Nemani
• Long Cao
• George Ban-Weiss
• Ho-Jeong Shin
Article

## Abstract

Recent studies have shown that changes in solar radiation affect the hydrological cycle more strongly than equivalent CO2 changes for the same change in global mean surface temperature. Thus, solar radiation management “geoengineering” proposals to completely offset global mean temperature increases by reducing the amount of absorbed sunlight might be expected to slow the global water cycle and reduce runoff over land. However, proposed countering of global warming by increasing the albedo of marine clouds would reduce surface solar radiation only over the oceans. Here, for an idealized scenario, we analyze the response of temperature and the hydrological cycle to increased reflection by clouds over the ocean using an atmospheric general circulation model coupled to a mixed layer ocean model. When cloud droplets are reduced in size over all oceans uniformly to offset the temperature increase from a doubling of atmospheric CO2, the global-mean precipitation and evaporation decreases by about 1.3% but runoff over land increases by 7.5% primarily due to increases over tropical land. In the model, more reflective marine clouds cool the atmospheric column over ocean. The result is a sinking motion over oceans and upward motion over land. We attribute the increased runoff over land to this increased upward motion over land when marine clouds are made more reflective. Our results suggest that, in contrast to other proposals to increase planetary albedo, offsetting mean global warming by reducing marine cloud droplet size does not necessarily lead to a drying, on average, of the continents. However, we note that the changes in precipitation, evaporation and P-E are dominated by small but significant areas, and given the highly idealized nature of this study, a more thorough and broader assessment would be required for proposals of altering marine cloud properties on a large scale.

## Keywords

Climate change Global warming Geoengineering Solar radiation management Marine cloud-albedo enhancement Hydrological cycle

## Notes

### Acknowledgments

We thank Prof. J. Srinivasan of Divecha Center for Climate Change, Indian Institute of Science for suggestions which helped to improve this manuscript.

## Supplementary material

382_2010_868_MOESM1_ESM.doc (98 kb)
(DOC 97 kb)

## References

1. Allen MR, Ingram WJ (2002) Constraints on future changes in climate and the hydrologic cycle. Nature 419(6903):224–232
2. Andrews T, Forster PM, Gregory JM (2009) A surface energy perspective on climate change. J Clim 22:2557–2570
3. Angel R (2006) Feasibility of cooling the earth with a cloud of small spacecraft near the inner Lagrange point (L1). Proc Natl Acad Sci USA 103(46):17184–17189
4. Bala G (2009) Problems with geoengineering schemes to combat climate change. Curr Sci 96(1):41–48Google Scholar
5. Bala G, Duffy PB, Taylor KE (2008) Impact of geoengineering schemes on the global hydrological cycle. Proc Natl Acad Sci USA 105(22):7664–7669
6. Bala G, Caldeira K, Nemani R (2009) Fast versus slow response in climate change: implications for the global hydrological cycle. Clim Dyn. doi:
7. Bengtsson L (2006) Geo-engineering to confine climate change: is it at all feasible? Clim Change 77(3–4):229–234
8. Betts RA et al (2007) Projected increase in continental runoff due to plant responses to increasing carbon dioxide. Nature 448(7157):U5–U1037
9. Boucher O, Jones A, Betts RA (2009) Climate response to the physiological impact of carbon dioxide on plants in the Met Office Unified Model HadCM3. Clim Dyn 32(2–3):237–249
10. Bower K, Choularton T, Latham J, Sahraei J, Salter S (2006) Computational assessment of a proposed technique for global warming mitigation via albedo-enhancement of marine stratocumulus clouds. Atmos Res 82(1–2):328–336
11. Cao L, Bala G, Caldeira K, Nemani R, Ban-Weiss G (2009) Climate response to physiological forcing of carbon dioxide simulated by the coupled community atmosphere model (CAM3.1) and community land model (CLM3.0). Geophys Res Lett 36:L10402. doi:
12. Collins WD et al (2006) The formulation and atmospheric simulation of the community atmosphere model version 3 (CAM3). J Clim 19(11):2144–2161
13. Crutzen PJ (2006) Albedo enhancement by stratospheric sulfur injections: a contribution to resolve a policy dilemma? Clim Change 77(3–4):211–219
14. Doutriaux-Boucher M, Webb MJ, Gregory JM, Boucher O (2009) Carbon dioxide induced stomatal closure increases radiative forcing via a rapid reduction in low cloud. Geophys Res Lett 36Google Scholar
15. Early JT (1989) The space based solar shield to offset greenhouse effect. J Br Interplanet Soc 42:567–569Google Scholar
16. Fasullo JT, Trenberth KE (2008a) The annual cycle of the energy budget. Part I: global mean and land-ocean exchanges. J Clim 21(10):2297–2312
17. Fasullo JT, Trenberth KE (2008b) The annual cycle of the energy budget. Part II: meridional structures and poleward transports. J Clim 21(10):2313–2325
18. Forster PM, Blackburn M, Glover R, Shine KP (2000) An examination of climate sensitivity for idealised climate change experiments in an intermediate general circulation model. Clim Dyn 16(10–11):833–849
19. Gedney N et al (2006) Detection of a direct carbon dioxide effect in continental river runoff records. Nature 439(7078):835–838
20. Govindasamy B, Caldeira K (2000) Geoengineering earth’s radiation balance to mitigate CO2-induced climate change. Geophys Res Lett 27(14):2141–2144
21. Govindasamy B, Thompson S, Duffy PB, Caldeira K, Delire C (2002) Impact of geoengineering schemes on the terrestrial biosphere. Geophys Res Lett 29(22):2061. doi:
22. Govindasamy B, Caldeira K, Duffy PB (2003) Geoengineering earth’s radiation balance to mitigate climate change from a quadrupling of CO2. Glob Planet Change 37(1–2):157–168
23. Gregory J, Webb M (2008) Tropospheric adjustment induces a cloud component in CO2 forcing. J Clim 21(1):58–71
24. Gregory JM et al (2004) A new method for diagnosing radiative forcing and climate sensitivity. Geophys Res Lett 31(3):L03205. doi:
25. Hansen J, Sato M, Ruedy R (1997) Radiative forcing and climate response. J Geophys Res Atmos 102(D6):6831–6864
26. Hansen J et al (2005) Efficacy of climate forcings. J Geophys Res Atmos 110(D18):D18104. doi:
27. Held IM, Soden BJ (2006) Robust responses of the hydrological cycle to global warming. J Clim 19(21):5686–5699
28. Holton J (1992) An introduction to dynamics meteorology, 5th edn. Academic Press, New York, USA, p 511Google Scholar
29. IPCC (2007) Climate change 2007: the physical science basis. Contribution of working group I to the fourth assessment report of the intergovernmental panel on climate change. Cambridge University Press, Cambridge, UK and New York, NY, USAGoogle Scholar
30. Jones A, Haywood J, Boucher O (2009) Climate impacts of geoengineering marine stratocumulus clouds. J Geophys Res Atmos 114:D10106. doi:
31. Joshi M, Gregory J (2008) Dependence of the land-sea contrast in surface climate response on the nature of the forcing. Geophys Res Lett 35(24)Google Scholar
32. Joshi MM, Gregory JM, Webb MJ, Sexton DMH, Johns TC (2008) Mechanisms for the land/sea warming contrast exhibited by simulations of climate change. Clim Dyn 30(5):455–465
33. Lambert FH, Chiang JCH (2007) Control of land-ocean temperature contrast by ocean heat uptake. Geophys Res Lett 34(13)Google Scholar
34. Latham J (1990) Control of global warming. Nature 347(6291):339–340
35. Latham J (2002) Amelioration of global warming by controlled enhancement of the albedo and longevity of low-level maritime clouds. Atmos Sci Lett. doi:
36. Latham J et al (2008) Global temperature stabilization via controlled albedo enhancement of low-level maritime clouds. Philos Trans Roy Soc Math Phys Eng Sci 366(1882):3969–3987
37. Lunt DJ, Ridgwell A, Valdes PJ, Seale A (2008) “Sunshade World”: a fully coupled GCM evaluation of the climatic impacts of geoengineering. Geophys Res Lett 35(12):L12710. doi:
38. Mathews D, Cao L, Caldeira K (2009) Sensitivity of ocean acidification to geoengineered climate stabilization. Geophys Res Lett 36:L10706. doi:
39. Matthews HD, Caldeira K (2007) Transient climate-carbon simulations of planetary geoengineering. Proc Natl Acad Sci USA 104(24):9949–9954
40. NAS 1992 (1992) Policy implications of greenhouse warming: mitigation, adaptation and the science base. National Academy of Sciences. National Academy Press, Washington ,DC, Chap. 28 (Geoengineering), pp 433–464Google Scholar
41. Oleson KW, et al (2008) Improvements to the Community Land Model and their impact on the hydrological cycle. J Geophys Res Biogeosci 113(G1)Google Scholar
42. Rasch PJ, Crutzen PJ, Coleman DB (2008) Exploring the geoengineering of climate using stratospheric sulfate aerosols: the role of particle size. Geophys Res Lett 35(2):L02809. doi:
43. Robock A, Oman L, Stenchikov GL (2008) Regional climate responses to geoengineering with tropical and Arctic SO2 injections. J Geophys Res 113:D16101. doi:
44. Schneider SH (2001) Earth systems engineering and management. Nat 409(6818):417–421
45. Seifritz W (1989) Mirrors to halt global warming. Nature 340(6235):603
46. Shin HJ, Chung IU, Kim HJ, Kim JW (2006) Global energy cycle between land and ocean in the simulated 20th century climate systems. Geophys Res Lett 33(14)Google Scholar
47. Stevens B, Feingold G (2009) Untangling aerosol effects on clouds and precipitation in a buffered system. Nature 461:607–613
48. Sutton RT, Dong BW, Gregory JM (2007) Land/sea warming ratio in response to climate change: IPCC AR4 model results and comparison with observations. Geophys Res Lett 34(2):L02701. doi:
49. Teller E, Wood L, Hyde R (1997) Global warming and ice ages: I. Prospects for physics based modulation of global change, UCRL-231636/UCRL JC 128715. Lawrence Livermore National Laboratory, Livermore, CA, USAGoogle Scholar
50. Tilmes S, Garcia RR, Kinnison DE, Gettelman A, Rasch P (2009) Impact of geoengineered aerosols on the troposphere and stratosphere. Geophys Res Lett 114:D12305. doi: Google Scholar
51. Trenberth KE, Dai A (2007) Effects of mount Pinatubo volcanic eruption on the hydrological cycle as an analog of geoengineering. Geophys Res Lett 34(15):L15702. doi:
52. Twomey S (1977) Influence of pollution on shortwave albedo of clouds. J Atmos Sci 34(7):1149–1152
53. Zwiers F, von Storch H (1995) Taking serial correlation into account in tests of the mean. J Clim 8:336–351

## Authors and Affiliations

• G. Bala
• 1
• 4
• Ken Caldeira
• 2
• Rama Nemani
• 3
• Long Cao
• 2
• George Ban-Weiss
• 2
• Ho-Jeong Shin
• 2
1. 1.Divecha Center for Climate ChangeIndian Institute of ScienceBangaloreIndia
2. 2.Department of Global EcologyCarnegie InstitutionStanfordUSA
3. 3.NASA Ames Research CenterMoffett FieldUSA
4. 4.Center for Atmospheric and Oceanic SciencesIndian Institute of ScienceBangaloreIndia
{"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8004799485206604, "perplexity": 29884.083895529304}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-39/segments/1537267155561.35/warc/CC-MAIN-20180918150229-20180918170229-00404.warc.gz"}