Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Multifaceted characteristics of dryland aridity changes in a warming world

Abstract

Drylands are an essential component of the Earth System and are among the most vulnerable to climate change. In this Review, we synthesize observational and modelling evidence to demonstrate emerging differences in dryland aridity dependent on the specific metric considered. Although warming heightens vapour pressure deficit and, thus, atmospheric demand for water in both the observations and the projections, these changes do not wholly propagate to exacerbate soil moisture and runoff deficits. Moreover, counter-intuitively, many arid ecosystems have exhibited significant greening and enhanced vegetation productivity since the 1980s. Such divergence between atmospheric and ecohydrological aridity changes can primarily be related to moisture limitations by dry soils and plant physiological regulations of evapotranspiration under elevated CO2. The latter process ameliorates water stress on plant growth and decelerates warming-enhanced water losses from soils, while simultaneously warming and drying the near-surface air. We place these climate-induced aridity changes in the context of exacerbated water scarcity driven by rapidly increasing anthropogenic needs for freshwater to support population growth and economic development. Under future warming, dryland ecosystems might respond non-linearly, caused by, for example, complex ecosystem–hydrology–human interactions and increased mortality risks from drought and heat stress, which is a foremost priority for future research.

Key points

  • Atmospheric, agricultural, hydrological and ecological indices of aridity reveal strongly divergent trends since 1950 and into the near future.

  • Warming-driven increases in vapour pressure deficit hasten evaporative water loss and deplete surface moisture, in turn amplifying atmospheric drying through land–atmosphere feedbacks.

  • Plant stomatal closure under elevated CO2 reduces transpiration and compensates for the adverse effect of higher vapour pressure deficit for plant growth, explaining the co-occurrence of ecosystem greening and atmospheric drying in drylands.

  • The physiologically induced lowering of evapotranspiration under rising CO2, along with the strong limitation by soil moisture, disconnects atmospheric drying and hydrological responses in drylands.

  • With rapid climate change and population growth, anthropogenic water demand in drylands is projected to increase by ~270% by the 2090s, exacerbating current water resource scarcity.

  • As future water deficits are driven mainly by increasing water demand, sustainable water resource management and water conservation technologies are needed to balance the socio-economic demands for water resources while maintaining healthy dryland ecosystems.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.

from$8.99

All prices are NET prices.

Fig. 1: Global drylands and ecohydrological conditions.
Fig. 2: Past and future dryland changes evaluated by five different aridity metrics.
Fig. 3: Continental assessment of future dryland changes.
Fig. 4: Physical and physiological mechanisms for dryland aridity changes.
Fig. 5: Dryland anthropogenic water stress under climatic and socio-economic changes.
Fig. 6: Conceptual diagram of future dryland aridity changes.

References

  1. 1.

    Reynolds, J. F. et al. Global desertification: building a science for dryland development. Science 316, 847–851 (2007).

    Google Scholar 

  2. 2.

    Huang, J. et al. Dryland climate change: recent progress and challenges. Rev. Geophys. 55, 719–778 (2017).

    Google Scholar 

  3. 3.

    Intergovernmental Panel on Climate Change (IPCC). Climate Change and Land: An IPCC Special Report on Climate Change, Desertification, Land Degradation, Sustainable Land Management, Food Security, and Greenhouse Gas Fluxes in Terrestrial Ecosystems (eds Akhtar-Schuster, M., Driouech, F. & Sankaran, M.) Ch. 3 (IPCC, Cambridge Univ. Press, 2019).

  4. 4.

    Prăvălie, R. Drylands extent and environmental issues. A global approach. Earth Sci. Rev. 161, 259–278 (2016).

    Google Scholar 

  5. 5.

    D’Odorico, P., Bhattachan, A., Davis, K. F., Ravi, S. & Runyan, C. W. Global desertification: drivers and feedbacks. Adv. Water Resour. 51, 326–344 (2013).

    Google Scholar 

  6. 6.

    Ahlström, A. et al. The dominant role of semi-arid ecosystems in the trend and variability of the land CO2 sink. Science 348, 895–899 (2015). Highlights the critical role of drylands in the global carbon budget by demonstrating that semi-arid ecosystems dominate the inter-annual variability and the increasing trend of global terrestrial carbon sink.

    Google Scholar 

  7. 7.

    Maestre, F. T. et al. Plant species richness and ecosystem multifunctionality in global drylands. Science 335, 214–218 (2012).

    Google Scholar 

  8. 8.

    Millennium Ecosystem Assessment. Ecosystems and Human Well-Being: Desertification Synthesis (World Resources Institute, 2005).

  9. 9.

    El-Beltagy, A. & Madkour, M. Impact of climate change on arid lands agriculture. Agric. Food Secur. 1, 3 (2012).

    Google Scholar 

  10. 10.

    Huang, J., Yu, H., Guan, X., Wang, G. & Guo, R. Accelerated dryland expansion under climate change. Nat. Clim. Change 6, 166–171 (2016).

    Google Scholar 

  11. 11.

    Cook, K. H. & Vizy, E. K. Detection and analysis of an amplified warming of the Sahara Desert. J. Clim. 28, 6560–6580 (2015).

    Google Scholar 

  12. 12.

    Zhou, L., Chen, H. & Dai, Y. Stronger warming amplification over drier ecoregions observed since 1979. Environ. Res. Lett. 10, 064012 (2015).

    Google Scholar 

  13. 13.

    Fu, B. et al. The Global-DEP conceptual framework — research on dryland ecosystems to promote sustainability. Curr. Opin. Environ. Sustain. 48, 17–28 (2021). Proposes a conceptual framework that aims to facilitate actionable pathways towards sustainable development of global dryland socio-ecological systems.

    Google Scholar 

  14. 14.

    Larigauderie, A. & Mooney, H. A. The Intergovernmental science-policy Platform on Biodiversity and Ecosystem Services: moving a step closer to an IPCC-like mechanism for biodiversity. Curr. Opin. Environ. Sustain. 2, 9–14 (2010).

    Google Scholar 

  15. 15.

    Convention on Biological Diversity. Aichi Biodiversity Targets http://www.cbd.int/sp/targets/default.shtml (2010).

  16. 16.

    United Nations. Transforming Our World: The 2030 Agenda for Sustainable Development (United Nations General Assembly, 2015).

  17. 17.

    Park, C.-E. et al. Keeping global warming within 1.5 °C constrains emergence of aridification. Nat. Clim. Change 8, 70–74 (2018).

    Google Scholar 

  18. 18.

    Sherwood, S. & Fu, Q. A drier future? Science 343, 737–739 (2014).

    Google Scholar 

  19. 19.

    Ukkola, A. M. et al. Reduced streamflow in water-stressed climates consistent with CO2 effects on vegetation. Nat. Clim. Change 6, 75–78 (2015).

    Google Scholar 

  20. 20.

    Wang, J. et al. Recent global decline in endorheic basin water storages. Nat. Geosci. 11, 926–932 (2018). Provides observational evidence for widespread loss of terrestrial water storage over global endorheic basins during 2002–2016 from climate variability and human water extractions.

    Google Scholar 

  21. 21.

    Scheff, J. & Frierson, D. M. W. Terrestrial aridity and its response to greenhouse warming across CMIP5 climate models. J. Clim. 28, 5583–5600 (2015).

    Google Scholar 

  22. 22.

    Koutroulis, A. G. Dryland changes under different levels of global warming. Sci. Total Environ. 655, 482–511 (2019).

    Google Scholar 

  23. 23.

    Schewe, J. et al. Multimodel assessment of water scarcity under climate change. Proc. Natl Acad. Sci. USA 111, 3245–3250 (2014).

    Google Scholar 

  24. 24.

    Feng, S. & Fu, Q. Expansion of global drylands under a warming climate. Atmos. Chem. Phys. Discuss. 13, 14637–14665 (2013).

    Google Scholar 

  25. 25.

    Cook, B. I., Smerdon, J. E., Seager, R. & Coats, S. Global warming and 21st century drying. Clim. Dyn. 43, 2607–2627 (2014).

    Google Scholar 

  26. 26.

    Zhang, P. et al. Abrupt shift to hotter and drier climate over inner East Asia beyond the tipping point. Science 370, 1095–1099 (2020).

    Google Scholar 

  27. 27.

    He, B., Wang, S., Guo, L. & Wu, X. Aridity change and its correlation with greening over drylands. Agric. For. Meteorol. 278, 107663 (2019).

    Google Scholar 

  28. 28.

    Donohue, R. J., Roderick, M. L., McVicar, T. R. & Farquhar, G. D. Impact of CO2 fertilization on maximum foliage cover across the globe’s warm, arid environments. Geophys. Res. Lett. 40, 3031–3035 (2013). Reveals widespread greening in global arid regions despite warming, and provides quantitative theoretical evidence linking this greening pattern with elevated CO2.

    Google Scholar 

  29. 29.

    Fensholt, R. et al. Greenness in semi-arid areas across the globe 1981–2007 — an Earth Observing Satellite based analysis of trends and drivers. Remote Sens. Environ. 121, 144–158 (2012).

    Google Scholar 

  30. 30.

    Andela, N., Liu, Y. Y., van Dijk, A. I. J. M., de Jeu, R. A. M. & McVicar, T. R. Global changes in dryland vegetation dynamics (1988–2008) assessed by satellite remote sensing: comparing a new passive microwave vegetation density record with reflective greenness data. Biogeosciences 10, 6657–6676 (2013).

    Google Scholar 

  31. 31.

    Zhu, Z. et al. Greening of the Earth and its drivers. Nat. Clim. Change 6, 791–795 (2016).

    Google Scholar 

  32. 32.

    Piao, S. et al. Characteristics, drivers and feedbacks of global greening. Nat. Rev. Earth Environ. 1, 14–27 (2020).

    Google Scholar 

  33. 33.

    Beck, H. E. et al. Global evaluation of four AVHRR–NDVI data sets: Intercomparison and assessment against Landsat imagery. Remote Sens. Environ. 115, 2547–2563 (2011).

    Google Scholar 

  34. 34.

    United Nations World Water Assessment Programme. The United Nations World Water Development Report 2015: Water for a Sustainable World (UNESCO, 2015).

  35. 35.

    Wang, L. et al. Dryland ecohydrology and climate change: critical issues and technical advances. Hydrol. Earth Syst. Sci. 16, 2585–2603 (2012).

    Google Scholar 

  36. 36.

    Roderick, M. L., Greve, P. & Farquhar, G. D. On the assessment of aridity with changes in atmospheric CO2. Water Resour. Res. 51, 5450–5463 (2015). A comprehensive summary of contradictory viewpoints of ‘warmer is more arid’ versus ‘warmer is less arid’ that arise from different interpretations of aridity changes, and provides a road map for reconciling such disparities.

    Google Scholar 

  37. 37.

    Swann, A. L. S. Plants and drought in a changing climate. Curr. Clim. Change Rep. 4, 192–201 (2018).

    Google Scholar 

  38. 38.

    Greve, P. et al. Global assessment of trends in wetting and drying over land. Nat. Geosci. 7, 716–721 (2014).

    Google Scholar 

  39. 39.

    Smith, W. K. et al. Remote sensing of dryland ecosystem structure and function: progress, challenges, and opportunities. Remote Sens. Environ. 233, 111401 (2019).

    Google Scholar 

  40. 40.

    Greve, P., Roderick, M. L., Ukkola, A. M. & Wada, Y. The aridity index under global warming. Environ. Res. Lett. 14, 124006 (2019).

    Google Scholar 

  41. 41.

    Huang, J., Yu, H., Dai, A., Wei, Y. & Kang, L. Drylands face potential threat under 2°C global warming target. Nat. Clim. Change 7, 417–422 (2017).

    Google Scholar 

  42. 42.

    Middleton, N. & Thomas, D. World Atlas of Desertification (Arnold, 1997).

  43. 43.

    Fu, Q. & Feng, S. Responses of terrestrial aridity to global warming. J. Geophys. Res. Atmos. 119, 7863–7875 (2014).

    Google Scholar 

  44. 44.

    Yang, Y. et al. Disconnection between trends of atmospheric drying and continental runoff. Water Resour. Res. 54, 4700–4713 (2018).

    Google Scholar 

  45. 45.

    Yang, Y., Roderick, M. L., Zhang, S., McVicar, T. R. & Donohue, R. J. Hydrologic implications of vegetation response to elevated CO2 in climate projections. Nat. Clim. Change 9, 44–48 (2019).

    Google Scholar 

  46. 46.

    Greve, P., Roderick, M. L. & Seneviratne, S. I. Simulated changes in aridity from the last glacial maximum to 4xCO2. Environ. Res. Lett. 12, 114021 (2017).

    Google Scholar 

  47. 47.

    Yuan, W. et al. Increased atmospheric vapor pressure deficit reduces global vegetation growth. Sci. Adv. 5, eaax1396 (2019).

    Google Scholar 

  48. 48.

    Zhou, S. et al. Land–atmosphere feedbacks exacerbate concurrent soil drought and atmospheric aridity. Proc. Natl Acad. Sci. USA 116, 18848–18853 (2019).

    Google Scholar 

  49. 49.

    Grossiord, C. et al. Plant responses to rising vapor pressure deficit. New Phytol. 226, 1550–1566 (2020).

    Google Scholar 

  50. 50.

    Berdugo, M. et al. Global ecosystem thresholds driven by aridity. Science 367, 787–790 (2020).

    Google Scholar 

  51. 51.

    Keenan, T. F., Luo, X., Zhang, Y. & Zhou, S. Ecosystem aridity and atmospheric CO2. Science 368, 251–252 (2020).

    Google Scholar 

  52. 52.

    Burrell, A. L., Evans, J. P. & De Kauwe, M. G. Anthropogenic climate change has driven over 5 million km2 of drylands towards desertification. Nat. Commun. 11, 3853 (2020).

    Google Scholar 

  53. 53.

    Trenberth, K. E. et al. Global warming and changes in drought. Nat. Clim. Change 4, 17–22 (2013).

    Google Scholar 

  54. 54.

    Milly, P. C. D. & Dunne, K. A. Potential evapotranspiration and continental drying. Nat. Clim. Change 6, 946–949 (2016).

    Google Scholar 

  55. 55.

    Milly, P. & Dunne, K. A. A hydrologic drying bias in water-resource impact analyses of anthropogenic climate change. J. Am. Water Resour. Assoc. 53, 822–838 (2017).

    Google Scholar 

  56. 56.

    De Jeu, R. A. et al. Global soil moisture patterns observed by space borne microwave radiometers and scatterometers. Surv. Geophys. 29, 399–420 (2008).

    Google Scholar 

  57. 57.

    Berg, A. & Sheffield, J. Climate change and drought: the soil moisture perspective. Curr. Clim. Change Rep. 4, 180–191 (2018).

    Google Scholar 

  58. 58.

    Feng, H. & Zhang, M. Global land moisture trends: drier in dry and wetter in wet over land. Sci. Rep. 5, 18018 (2015).

    Google Scholar 

  59. 59.

    Berg, A., Sheffield, J. & Milly, P. C. D. Divergent surface and total soil moisture projections under global warming. Geophys. Res. Lett. 44, 236–244 (2017).

    Google Scholar 

  60. 60.

    Cook, B. I. et al. Twenty-first century drought projections in the CMIP6 forcing scenarios. Earths Future 8, e2019EF001461 (2020).

    Google Scholar 

  61. 61.

    Li, M., Wu, P., Ma, Z., Lv, M. & Yang, Q. Changes in soil moisture persistence in China over the past 40 years under a warming climate. J. Clim. 33, 9531–9550 (2020).

    Google Scholar 

  62. 62.

    Rodell, M. et al. Emerging trends in global freshwater availability. Nature 557, 651–659 (2018).

    Google Scholar 

  63. 63.

    Dai, A., Zhao, T. & Chen, J. Climate change and drought: a precipitation and evaporation perspective. Curr. Clim. Change Rep. 4, 301–312 (2018). Highlights the dominant role of CO2 radiative forcing in shaping global land surface drying patterns for the twenty-first century.

    Google Scholar 

  64. 64.

    Schlaepfer, D. R. et al. Climate change reduces extent of temperate drylands and intensifies drought in deep soils. Nat. Commun. 8, 14196 (2017).

    Google Scholar 

  65. 65.

    Li, L. et al. Global trends in water and sediment fluxes of the world’s large rivers. Sci. Bull. 65, 62–69 (2019).

    Google Scholar 

  66. 66.

    Yang, H. et al. Regional patterns of future runoff changes from Earth system models constrained by observation. Geophys. Res. Lett. 44, 5540–5549 (2017).

    Google Scholar 

  67. 67.

    Wang, S. et al. Reduced sediment transport in the Yellow River due to anthropogenic changes. Nat. Geosci. 9, 38–41 (2015).

    Google Scholar 

  68. 68.

    Milly, P. C. D. & Dunne, K. A. Colorado River flow dwindles as warming-driven loss of reflective snow energizes evaporation. Science 367, 1252–1255 (2020).

    Google Scholar 

  69. 69.

    Trancoso, R., Larsen, J. R., McVicar, T. R., Phinn, S. R. & McAlpine, C. A. CO2-vegetation feedbacks and other climate changes implicated in reducing base flow. Geophys. Res. Lett. 44, 2310–2318 (2017).

    Google Scholar 

  70. 70.

    Dai, A., Qian, T., Trenberth, K. E. & Milliman, J. D. Changes in continental freshwater discharge from 1948 to 2004. J. Clim. 22, 2773–2792 (2009).

    Google Scholar 

  71. 71.

    Hobeichi, S., Abramowitz, G., Evans, J. & Beck, H. E. Linear Optimal Runoff Aggregate (LORA): A global gridded synthesis runoff product. Hydrol. Earth Syst. Sci. 23, 851–870 (2019).

    Google Scholar 

  72. 72.

    Novick, K. A. et al. The increasing importance of atmospheric demand for ecosystem water and carbon fluxes. Nat. Clim. Change 6, 1023–1027 (2016).

    Google Scholar 

  73. 73.

    Chen, C. et al. China and India lead in greening of the world through land-use management. Nat. Sustain. 2, 122–129 (2019).

    Google Scholar 

  74. 74.

    Eyring, V. et al. Overview of the Coupled Model Intercomparison Project Phase 6 (CMIP6) experimental design and organization. Geosci. Model Dev. 9, 1937–1958 (2016).

    Google Scholar 

  75. 75.

    Eyring, V. et al. Taking climate model evaluation to the next level. Nat. Clim. Change 9, 102–110 (2019).

    Google Scholar 

  76. 76.

    Berg, A. et al. Land–atmosphere feedbacks amplify aridity increase over land under global warming. Nat. Clim. Change 6, 869–874 (2016). Reveals the important mechanism that declining soil moisture and altered vegetation physiology under climate change and rising CO2 could make the near-surface air even warmer and drier.

    Google Scholar 

  77. 77.

    Stephens, C. M., McVicar, T. R., Johnson, F. M. & Marshall, L. A. Revisiting pan evaporation trends in Australia a decade on. Geophys. Res. Lett. 45, 11164–11172 (2018).

    Google Scholar 

  78. 78.

    Byrne, M. P. & O’Gorman, P. A. The response of precipitation minus evapotranspiration to climate warming: why the “wet-get-wetter, dry-get-drier” scaling does not hold over land. J. Clim. 28, 8078–8092 (2015).

    Google Scholar 

  79. 79.

    Zhou, S. et al. Soil moisture–atmosphere feedbacks mitigate declining water availability in drylands. Nat. Clim. Change 11, 38–44 (2020).

    Google Scholar 

  80. 80.

    Lau, W. K. & Kim, K. M. Robust Hadley circulation changes and increasing global dryness due to CO2 warming from CMIP5 model projections. Proc. Natl Acad. Sci. USA 112, 3630–3635 (2015).

    Google Scholar 

  81. 81.

    Lau, W. K. M. & Tao, W. Precipitation–radiation–circulation feedback processes associated with structural changes of the ITCZ in a warming climate during 1980–2014: an observational portrayal. J. Clim. 33, 8737–8749 (2020).

    Google Scholar 

  82. 82.

    Burls, N. J. & Fedorov, A. V. Wetter subtropics in a warmer world: contrasting past and future hydrological cycles. Proc. Natl Acad. Sci. USA 114, 12888–12893 (2017).

    Google Scholar 

  83. 83.

    Condon, L. E., Atchley, A. L. & Maxwell, R. M. Evapotranspiration depletes groundwater under warming over the contiguous United States. Nat. Commun. 11, 873 (2020).

    Google Scholar 

  84. 84.

    Jung, M. et al. Recent decline in the global land evapotranspiration trend due to limited moisture supply. Nature 467, 951–954 (2010).

    Google Scholar 

  85. 85.

    García, M. et al. Actual evapotranspiration in drylands derived from in-situ and satellite data: Assessing biophysical constraints. Remote Sens. Environ. 131, 103–118 (2013).

    Google Scholar 

  86. 86.

    Betts, R. A. et al. Projected increase in continental runoff due to plant responses to increasing carbon dioxide. Nature 448, 1037–1041 (2007).

    Google Scholar 

  87. 87.

    Swann, A. L., Hoffman, F. M., Koven, C. D. & Randerson, J. T. Plant responses to increasing CO2 reduce estimates of climate impacts on drought severity. Proc. Natl Acad. Sci. USA 113, 10019–10024 (2016).

    Google Scholar 

  88. 88.

    Fowler, M. D., Kooperman, G. J., Randerson, J. T. & Pritchard, M. S. The effect of plant physiological responses to rising CO2 on global streamflow. Nat. Clim. Change 9, 873–879 (2019).

    Google Scholar 

  89. 89.

    Lemordant, L., Gentine, P., Swann, A. S., Cook, B. I. & Scheff, J. Critical impact of vegetation physiology on the continental hydrologic cycle in response to increasing CO2. Proc. Natl Acad. Sci. USA 115, 4093–4098 (2018).

    Google Scholar 

  90. 90.

    Haverd, V. et al. Higher than expected CO2 fertilization inferred from leaf to global observations. Glob. Change Biol. 26, 2390–2402 (2020).

    Google Scholar 

  91. 91.

    Nie, M., Lu, M., Bell, J., Raut, S. & Pendall, E. Altered root traits due to elevated CO2: a meta-analysis. Glob. Ecol. Biogeogr. 22, 1095–1105 (2013).

    Google Scholar 

  92. 92.

    Zhang, Y. et al. Multi-decadal trends in global terrestrial evapotranspiration and its components. Sci. Rep. 6, 19124 (2016).

    Google Scholar 

  93. 93.

    Sun, X., Wilcox, B. P. & Zou, C. B. Evapotranspiration partitioning in dryland ecosystems: A global meta-analysis of in situ studies. J. Hydrol. 576, 123–136 (2019).

    Google Scholar 

  94. 94.

    Lian, X. et al. Partitioning global land evapotranspiration using CMIP5 models constrained by observations. Nat. Clim. Change 8, 640–646 (2018).

    Google Scholar 

  95. 95.

    Yang, H., Huntingford, C., Wiltshire, A., Sitch, S. & Mercado, L. Compensatory climate effects link trends in global runoff to rising atmospheric CO2 concentration. Environ. Res. Lett. 14, 124075 (2019).

    Google Scholar 

  96. 96.

    Mankin, J. S. et al. Blue water trade-offs with vegetation in a CO2-enriched climate. Geophys. Res. Lett. 45, 3115–3125 (2018).

    Google Scholar 

  97. 97.

    Stocker, B. D. et al. Quantifying soil moisture impacts on light use efficiency across biomes. New Phytol. 218, 1430–1449 (2018).

    Google Scholar 

  98. 98.

    Liu, L. et al. Soil moisture dominates dryness stress on ecosystem production globally. Nat. Commun. 11, 4892 (2020).

    Google Scholar 

  99. 99.

    Morgan, J. A. et al. C4 grasses prosper as carbon dioxide eliminates desiccation in warmed semi-arid grassland. Nature 476, 202–205 (2011).

    Google Scholar 

  100. 100.

    Farrior, C. E., Rodriguez-Iturbe, I., Dybzinski, R., Levin, S. A. & Pacala, S. W. Decreased water limitation under elevated CO2 amplifies potential for forest carbon sinks. Proc. Natl Acad. Sci. USA 112, 7213–7218 (2015).

    Google Scholar 

  101. 101.

    Lu, X., Wang, L. & McCabe, M. F. Elevated CO2 as a driver of global dryland greening. Sci. Rep. 6, 20716 (2016).

    Google Scholar 

  102. 102.

    Ukkola, A. M., Keenan, T. F., Kelley, D. I. & Prentice, I. C. Vegetation plays an important role in mediating future water resources. Environ. Res. Lett. 11, 094022 (2016).

    Google Scholar 

  103. 103.

    Mankin, J. S., Smerdon, J. E., Cook, B. I., Williams, A. P. & Seager, R. The curious case of projected twenty-first-century drying but greening in the American West. J. Clim. 30, 8689–8710 (2017).

    Google Scholar 

  104. 104.

    Zarakas, C. M., Swann, A. L. S., Laguë, M. M., Armour, K. C. & Randerson, J. T. Plant physiology increases the magnitude and spread of the transient climate response to CO2 in CMIP6 Earth system models. J. Clim. 33, 8561–8578 (2020).

    Google Scholar 

  105. 105.

    Mankin, J. S., Seager, R., Smerdon, J. E., Cook, B. I. & Williams, A. P. Mid-latitude freshwater availability reduced by projected vegetation responses to climate change. Nat. Geosci. 12, 983–988 (2019).

    Google Scholar 

  106. 106.

    Song, J. et al. Elevated CO2 does not stimulate carbon sink in a semi-arid grassland. Ecol. Lett. 22, 458–468 (2019).

    Google Scholar 

  107. 107.

    Obermeier, W. A. et al. Reduced CO2 fertilization effect in temperate C3 grasslands under more extreme weather conditions. Nat. Clim. Change 7, 137–141 (2016).

    Google Scholar 

  108. 108.

    Craine, J. M. et al. Isotopic evidence for oligotrophication of terrestrial ecosystems. Nat. Ecol. Evol. 2, 1735–1744 (2018).

    Google Scholar 

  109. 109.

    Medlyn, B. E. et al. How do leaf and ecosystem measures of water-use efficiency compare? New Phytol. 216, 758–770 (2017).

    Google Scholar 

  110. 110.

    Keenan, T. F. et al. Increase in forest water-use efficiency as atmospheric carbon dioxide concentrations rise. Nature 499, 324–327 (2013).

    Google Scholar 

  111. 111.

    Peters, W. et al. Increased water-use efficiency and reduced CO2 uptake by plants during droughts at a continental-scale. Nat. Geosci. 11, 744–748 (2018).

    Google Scholar 

  112. 112.

    Skinner, C. B., Poulsen, C. J. & Mankin, J. S. Amplification of heat extremes by plant CO2 physiological forcing. Nat. Commun. 9, 1094 (2018).

    Google Scholar 

  113. 113.

    Lemordant, L. & Gentine, P. Vegetation response to rising CO2 impacts extreme temperatures. Geophys. Res. Lett. 46, 1383–1392 (2019).

    Google Scholar 

  114. 114.

    Sellers, P. J. et al. Comparison of radiative and physiological effects of doubled atmospheric CO2 on climate. Science 271, 1402–1406 (1996).

    Google Scholar 

  115. 115.

    Warren, J. M., Norby, R. J. & Wullschleger, S. D. Elevated CO2 enhances leaf senescence during extreme drought in a temperate forest. Tree Physiol. 31, 117–130 (2011).

    Google Scholar 

  116. 116.

    De Kauwe, M. G. et al. Examining the evidence for decoupling between photosynthesis and transpiration during heat extremes. Biogeosciences 16, 903–916 (2019).

    Google Scholar 

  117. 117.

    Huang, M. et al. Air temperature optima of vegetation productivity across global biomes. Nat. Ecol. Evol. 3, 772–779 (2019).

    Google Scholar 

  118. 118.

    Reich, P. B., Hobbie, S. E., Lee, T. D. & Pastore, M. A. Unexpected reversal of C3 versus C4 grass response to elevated CO2 during a 20-year field experiment. Science 360, 317–320 (2018).

    Google Scholar 

  119. 119.

    Norby, R. J. et al. Model-data synthesis for the next generation of forest free-air CO2 enrichment (FACE) experiments. New Phytol. 209, 17–28 (2016).

    Google Scholar 

  120. 120.

    Steffen, W. et al. The emergence and evolution of Earth System Science. Nat. Rev. Earth Environ. 1, 54–63 (2020).

    Google Scholar 

  121. 121.

    Hoekstra, A. Y. & Mekonnen, M. M. The water footprint of humanity. Proc. Natl Acad. Sci. USA 109, 3232–3237 (2012).

    Google Scholar 

  122. 122.

    Marvel, K. et al. Twentieth-century hydroclimate changes consistent with human influence. Nature 569, 59–65 (2019).

    Google Scholar 

  123. 123.

    Di Baldassarre, G. et al. Sociohydrology: scientific challenges in addressing the sustainable development goals. Water Resour. Res. 55, 6327–6355 (2019).

    Google Scholar 

  124. 124.

    van der Esch, S. et al. Exploring Future Changes in Land Use and Land Condition and the Impacts on Food, Water, Climate Change and Biodiversity: Scenarios for the UNCCD Global Land Outlook (PBL Netherlands Environmental Assessment Agency, 2017).

  125. 125.

    Gleick, P. H. Transitions to freshwater sustainability. Proc. Natl Acad. Sci. USA 115, 8863–8871 (2018).

    Google Scholar 

  126. 126.

    Wada, Y., de Graaf, I. E. M. & van Beek, L. P. H. High-resolution modeling of human and climate impacts on global water resources. J. Adv. Model Earth Syst. 8, 735–763 (2016).

    Google Scholar 

  127. 127.

    Wada, Y. et al. Modeling global water use for the 21st century: the Water Futures and Solutions (WFaS) initiative and its approaches. Geosci. Model Dev. 9, 175–222 (2016). Provides an ensemble model projection of significant increases in the twenty-first century’s water demand by major water-use sectors under envisaged population growth and socio-economic developments.

    Google Scholar 

  128. 128.

    Wada, Y., van Beek, L. P. H. & Bierkens, M. F. P. Nonsustainable groundwater sustaining irrigation: a global assessment. Water Resour. Res. 48, W00L06 (2012).

    Google Scholar 

  129. 129.

    Chen, Y. et al. Recent global cropland water consumption constrained by observations. Water Resour. Res. 55, 3708–3738 (2019).

    Google Scholar 

  130. 130.

    Allen, L. H. Jr., Kakani, V. G., Vu, J. C. & Boote, K. J. Elevated CO2 increases water use efficiency by sustaining photosynthesis of water-limited maize and sorghum. J. Plant Physiol. 168, 1909–1918 (2011).

    Google Scholar 

  131. 131.

    Elliott, J. et al. Constraints and potentials of future irrigation water availability on agricultural production under climate change. Proc. Natl Acad. Sci. USA 111, 3239–3244 (2014).

    Google Scholar 

  132. 132.

    Urban, D. W., Sheffield, J. & Lobell, D. B. Historical effects of CO2 and climate trends on global crop water demand. Nat. Clim. Change 7, 901–905 (2017).

    Google Scholar 

  133. 133.

    Gleeson, T., Wada, Y., Bierkens, M. F. & van Beek, L. P. Water balance of global aquifers revealed by groundwater footprint. Nature 488, 197–200 (2012).

    Google Scholar 

  134. 134.

    Bierkens, M. F. P. & Wada, Y. Non-renewable groundwater use and groundwater depletion: a review. Environ. Res. Lett. 14, 063002 (2019).

    Google Scholar 

  135. 135.

    Rodell, M., Velicogna, I. & Famiglietti, J. S. Satellite-based estimates of groundwater depletion in India. Nature 460, 999–1002 (2009).

    Google Scholar 

  136. 136.

    Feng, W. et al. Evaluation of groundwater depletion in North China using the Gravity Recovery and Climate Experiment (GRACE) data and ground-based measurements. Water Resour. Res. 49, 2110–2118 (2013).

    Google Scholar 

  137. 137.

    Eamus, D. & Froend, R. Groundwater-dependent ecosystems: the where, what and why of GDEs. Aust. J. Bot. 54, 91–96 (2006).

    Google Scholar 

  138. 138.

    Griebler, C. & Avramov, M. Groundwater ecosystem services: a review. Freshw. Sci. 34, 355–367 (2015).

    Google Scholar 

  139. 139.

    Devitt, T. J., Wright, A. M., Cannatella, D. C. & Hillis, D. M. Species delimitation in endangered groundwater salamanders: implications for aquifer management and biodiversity conservation. Proc. Natl Acad. Sci. USA 116, 2624–2633 (2019).

    Google Scholar 

  140. 140.

    Feng, X. et al. Revegetation in China’s Loess Plateau is approaching sustainable water resource limits. Nat. Clim. Change 6, 1019–1022 (2016).

    Google Scholar 

  141. 141.

    Hong, S. et al. Divergent responses of soil organic carbon to afforestation. Nat. Sustain. 3, 694–700 (2020).

    Google Scholar 

  142. 142.

    McVicar, T. R. et al. Developing a decision support tool for China’s re-vegetation program: Simulating regional impacts of afforestation on average annual streamflow in the Loess Plateau. For. Ecol. Manag. 251, 65–81 (2007).

    Google Scholar 

  143. 143.

    Zhao, M. et al. Ecological restoration impact on total terrestrial water storage. Nat. Sustain. 4, 56–62 (2020).

    Google Scholar 

  144. 144.

    Kwon, H.-Y. et al. in Economics of Land Degradation and Improvement – A Global Assessment for Sustainable Development Ch. 8 (eds Nkonya E., Mirzabaev A. & von Braun J.) 197-214 (Springer, 2016).

  145. 145.

    Asner, G. P., Elmore, A. J., Olander, L. P., Martin, R. E. & Harris, A. T. Grazing systems, ecosystem responses, and global change. Annu. Rev. Environ. Resour. 29, 261–299 (2004).

    Google Scholar 

  146. 146.

    Dunne, T., Western, D. & Dietrich, W. E. Effects of cattle trampling on vegetation, infiltration, and erosion in a tropical rangeland. J. Arid. Environ. 75, 58–69 (2011).

    Google Scholar 

  147. 147.

    Griscom, B. W. et al. Natural climate solutions. Proc. Natl Acad. Sci. USA 114, 11645–11650 (2017).

    Google Scholar 

  148. 148.

    Lewis, S. L., Wheeler, C. E., Mitchard, E. T. & Koch, A. Restoring natural forests is the best way to remove atmospheric carbon. Nature 568, 25–28 (2019).

    Google Scholar 

  149. 149.

    Reisman-Berman, O., Keasar, T. & Tel-Zur, N. Native and non-native species for dryland afforestation: bridging ecosystem integrity and livelihood support. Ann. For. Sci. 76, 114 (2019).

    Google Scholar 

  150. 150.

    Zhang, J. et al. Carrying capacity for vegetation across northern China drylands. Sci. Total Environ. 710, 136391 (2020).

    Google Scholar 

  151. 151.

    Liu, Y., Kumar, M., Katul, G. G. & Porporato, A. Reduced resilience as an early warning signal of forest mortality. Nat. Clim. Change 9, 880–885 (2019).

    Google Scholar 

  152. 152.

    Fita, A., Rodríguez-Burruezo, A., Boscaiu, M., Prohens, J. & Vicente, O. Breeding and domesticating crops adapted to drought and salinity: a new paradigm for increasing food production. Front. Plant Sci. 6, 978 (2015).

    Google Scholar 

  153. 153.

    Graham, N. T. et al. Water sector assumptions for the Shared Socioeconomic Pathways in an integrated modeling framework. Water Resour. Res. 54, 6423–6440 (2018).

    Google Scholar 

  154. 154.

    Muhs, D. R. The geologic records of dust in the Quaternary. Aeolian Res. 9, 3–48 (2013).

    Google Scholar 

  155. 155.

    Scheff, J., Seager, R., Liu, H. & Coats, S. Are glacials dry? Consequences for paleoclimatology and for greenhouse warming. J. Clim. 30, 6593–6609 (2017).

    Google Scholar 

  156. 156.

    Lambert, F. et al. Dust-climate couplings over the past 800,000 years from the EPICA Dome C ice core. Nature 452, 616–619 (2008).

    Google Scholar 

  157. 157.

    Salzmann, U. et al. Climate and environment of a Pliocene warm world. Palaeogeogr. Palaeoclimatol. Palaeoecol. 309, 1–8 (2011).

    Google Scholar 

  158. 158.

    Fu, Q., Lin, L., Huang, J., Feng, S. & Gettelman, A. Changes in terrestrial aridity for the period 850–2080 from the Community Earth System Model. J. Geophys. Res. Atmos. 121, 2857–2873 (2016).

    Google Scholar 

  159. 159.

    Prudhomme, C. et al. Hydrological droughts in the 21st century, hotspots and uncertainties from a global multimodel ensemble experiment. Proc. Natl Acad. Sci. USA 111, 3262–3267 (2014).

    Google Scholar 

  160. 160.

    Cook, B. I., Ault, T. R. & Smerdon, J. E. Unprecedented 21st century drought risk in the American Southwest and Central Plains. Sci. Adv. 1, e1400082 (2015).

    Google Scholar 

  161. 161.

    Ault, T. R. On the essentials of drought in a changing climate. Science 368, 256–260 (2020).

    Google Scholar 

  162. 162.

    Reichstein, M. et al. Climate extremes and the carbon cycle. Nature 500, 287–295 (2013).

    Google Scholar 

  163. 163.

    Anderegg, W. R. L., Kane, J. M. & Anderegg, L. D. L. Consequences of widespread tree mortality triggered by drought and temperature stress. Nat. Clim. Change 3, 30–36 (2012).

    Google Scholar 

  164. 164.

    Williams, A. P. et al. Forest responses to increasing aridity and warmth in the southwestern United States. Proc. Natl Acad. Sci. USA 107, 21289–21294 (2010).

    Google Scholar 

  165. 165.

    Pellegrini, A. F. A. et al. Fire frequency drives decadal changes in soil carbon and nitrogen and ecosystem productivity. Nature 553, 194–198 (2018).

    Google Scholar 

  166. 166.

    Bowman, D. M. J. S. et al. Vegetation fires in the Anthropocene. Nat. Rev. Earth Environ. 1, 500–515 (2020).

    Google Scholar 

  167. 167.

    Andela, N. et al. A human-driven decline in global burned area. Science 356, 1356–1362 (2017).

    Google Scholar 

  168. 168.

    Pechony, O. & Shindell, D. T. Driving forces of global wildfires over the past millennium and the forthcoming century. Proc. Natl Acad. Sci. USA 107, 19167–19170 (2010).

    Google Scholar 

  169. 169.

    Hoover, D. L., Knapp, A. K. & Smith, M. D. Resistance and resilience of a grassland ecosystem to climate extremes. Ecology 95, 2646–2656 (2014).

    Google Scholar 

  170. 170.

    Greve, P. et al. Global assessment of water challenges under uncertainty in water scarcity projections. Nat. Sustain. 1, 486–494 (2018).

    Google Scholar 

  171. 171.

    Scanlon, B. R. et al. Global models underestimate large decadal declining and rising water storage trends relative to GRACE satellite data. Proc. Natl Acad. Sci. USA 115, E1080–E1089 (2018).

    Google Scholar 

  172. 172.

    Abatzoglou, J. T., Dobrowski, S. Z., Parks, S. A. & Hegewisch, K. C. TerraClimate, a high-resolution global dataset of monthly climate and climatic water balance from 1958–2015. Sci. Data 5, 170191 (2018).

    Google Scholar 

  173. 173.

    Roderick, M. L., Sun, F., Lim, W. H. & Farquhar, G. D. A general framework for understanding the response of the water cycle to global warming over land and ocean. Hydrol. Earth Syst. Sci. 18, 1575–1589 (2014).

    Google Scholar 

  174. 174.

    Gudmundsson, L., Greve, P. & Seneviratne, S. I. The sensitivity of water availability to changes in the aridity index and other factors—A probabilistic analysis in the Budyko space. Geophys. Res. Lett. 43, 6985–6994 (2016).

    Google Scholar 

  175. 175.

    American Meteorological Society. Glossary of Meteorology http://glossary.ametsoc.org/wiki/Aridity (2000).

  176. 176.

    Allen, R. G., Pereira, L. S., Raes, D. & Smith, M. Crop Evapotranspiration — Guidelines for Computing Crop Water Requirements — FAO Irrigation and Drainage Paper 56 (Food and Agriculture Organization of the United Nations, 1998).

  177. 177.

    Dai, A. Drought under global warming: a review. Wiley Interdiscip. Rev. Clim. Change 2, 45–65 (2011).

    Google Scholar 

  178. 178.

    Dai A. in Terrestrial Water Cycle and Climate Change: Natural and Human-Induced Impacts 1st edn, Ch. 2 (eds Tang, Q. & Oki, T.) 17-37 (Wiley, 2016).

  179. 179.

    Sitch, S. et al. Trends and drivers of regional sources and sinks of carbon dioxide over the past two decades. Biogeosci. Discuss. 10, 20113–20177 (2013).

    Google Scholar 

  180. 180.

    Donohue, R. J., Roderick, M. L., McVicar, T. R. & Yang, Y. A simple hypothesis of how leaf and canopy-level transpiration and assimilation respond to elevated CO2 reveals distinct response patterns between disturbed and undisturbed vegetation. J. Geophys. Res. Biogeosci. 122, 168–184 (2017).

    Google Scholar 

  181. 181.

    Barton, C. V. M. et al. Effects of elevated atmospheric [CO2] on instantaneous transpiration efficiency at leaf and canopy scales in Eucalyptus saligna. Glob. Change Biol. 18, 585–595 (2012).

    Google Scholar 

  182. 182.

    Savvides, A. M. & Fotopoulos, V. Two inexpensive and non-destructive techniques to correct for smaller-than-gasket leaf area in gas exchange measurements. Front. Plant Sci. 9, 548 (2018).

    Google Scholar 

Download references

Acknowledgements

This study was supported by the National Natural Science Foundation of China (41991230, 41988101), the Second Tibetan Plateau Scientific Expedition and Research (STEP) program (grant no. 2019QZKK0405) and the Xplorer Prize.

Author information

Affiliations

Authors

Contributions

S.P. formulated the Review and identified the themes to be covered. X.L. performed the analyses and drafted the figures. X.L., S.P. and A.C. wrote the first draft of the manuscript. C.H., B.F., L.Z.X.L., J.H., J.S., A.M.B., T.F.K., T.R.M., Y.W., X.W., T.W., Y.Y. and M.L.R. reviewed and edited the manuscript before submission. All authors made substantial contributions to the discussion of content.

Corresponding author

Correspondence to Shilong Piao.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

Peer review information

Nature Reviews Earth & Environment thanks Aristeidis Koutroulis, Sujong Jeong and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

Publisher’s note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary information

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Lian, X., Piao, S., Chen, A. et al. Multifaceted characteristics of dryland aridity changes in a warming world. Nat Rev Earth Environ 2, 232–250 (2021). https://doi.org/10.1038/s43017-021-00144-0

Download citation

Further reading

Search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing