Research ArticleCLIMATOLOGY

Deadly heat waves projected in the densely populated agricultural regions of South Asia

+ See all authors and affiliations

Science Advances  02 Aug 2017:
Vol. 3, no. 8, e1603322
DOI: 10.1126/sciadv.1603322
  • Fig. 1 Spatial distribution of highest daily maximum wet-bulb temperature, TWmax (°C), in modern record (1979–2015).

    Global distribution of TWmax is computed using ERA-Interim 3-hourly data with 0.75° × 0.75° horizontal resolution. The enlarged domain highlights three distinguishable regions with higher TWmax: southwest Asia around the Persian/Arabian Gulf and Red Sea, South Asia in the Indus and Ganges river valleys, and eastern China. TWmax values below 27°C are not shown.

  • Fig. 2 Histograms of daily maximum wet-bulb temperature, TWmax (°C), and maps of the ensemble averaged 30-year TWmax.

    (A) The histograms are generated for the most populous cities in the selected regions for each scenario: HIST (blue), RCP4.5 (green), and RCP8.5 (red). Values within each panel correspond to the 2- and 25-year return period of the bias-corrected annual maxima of TWmax, and the x and y axes indicate TWmax (°C) and the number of occurrences on a logarithmic scale, respectively. The background image was obtained from NASA Visible Earth. (B to D) The spatial distributions of bias-corrected ensemble averaged 30-year TWmax for each GHG scenario: HIST (1976–2005) (B), RCP4.5 (2071–2100) (C), and RCP8.5 (2071–2100) (D).

  • Fig. 3 Vulnerability due to population density, poverty, and outdoor working conditions.

    (A to C) Maps of population density in people/km2 (A), GDP in U.S. dollars per capita (B), and agricultural land fraction (C). (D to F) Population fraction exposed at least once in the simulations to TWmax (D) and exposed to median of annual maxima of TWmax (E), and agricultural land fraction (crop and pasture) exposed at least once in the simulations to TWmax (F). Blue, green, and red lines represent the HIST (1976–2005), RCP4.5 (2071–2100), and RCP8.5 (2071–2100) scenarios, respectively. Data for 2000 population density (43), 2014 GDP (Indian Ministry of Statistics and Programme Implementation), and 2000 agricultural intensity (44) are regridded onto the MRCM grid.

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/3/8/e1603322/DC1

    Supplementary Text

    fig. S1. Bias-corrected annual TWmax return period for the most populous cities in the selected regions for each scenario.

    fig. S2. Seasonal cycle of the 30-year average monthly maximum TWmax after bias correction for the most populous cities in the selected regions for each scenario.

    fig. S3. April-May-July climatological frequency (days/year) of severe heat wave calculated using daily maximum temperature derived from MRCM historical simulation (1976–2005) and RCP4.5 and RCP8.5 projections (2071–2100).

    fig. S4. As in fig. S3 but for intensity (°C) of severe heat wave.

    fig. S5. Geographical settings and typical climatological conditions of the South Asian monsoon.

    fig. S6. Spatial distribution of June-July-August 30-year (1982–2011) climatology of TW and TWmax (°C) for ERA-Interim and the MRCM simulations driven by ERA-Interim.

    fig. S7. Spatial distribution of June-July-August 30-year climatology of TW and TWmax (°C) for ERA-Interim (1979–2008) and the MRCM ensemble of the three simulations (1976–2005) driven by three AOGCMs (CCSM4, MPI-ESM, and ACCESS).

    fig. S8. Spatial distribution of 95th percentile exceedance of TWmax (days/year) from ERA-Interim (1979–2008) and the MRCM ensemble of simulations (1975–2005) driven by three AOGCMs (CCSM4, MPI-ESM, and ACCESS).

    fig. S9. Histogram of TWmax (°C) at three stations (Punjab, Patna, and Lucknow) from in situ observations (1979–2008) and the MRCM simulations (1976–2005) driven by three AOGCMs (CCSM4, MPI-ESM, and ACCESS).

    fig. S10. Histograms of daily maximum temperature, Tmax (°C), and maps of the ensemble averaged 30-year Tmax.

    fig. S11. Bias-corrected annual Tmax return period for the most populous cities in the selected regions for each scenario.

    fig. S12. Conversion tables between NOAA National Weather Service Heat Index and TW.

    table S1. Horizontal resolution of the atmospheric and ocean components of the three AOGCMs used in this study.

    References (4547)

  • Supplementary Materials

    This PDF file includes:

    • Supplementary Text
    • fig. S1. Bias-corrected annual TWmax return period for the most populous cities in the selected regions for each scenario.
    • fig. S2. Seasonal cycle of the 30-year average monthly maximum TWmax after bias correction for the most populous cities in the selected regions for each scenario.
    • fig. S3. April-May-July climatological frequency (days/year) of severe heat wave calculated using daily maximum temperature derived from MRCM historical simulation (1976–2005) and RCP4.5 and RCP8.5 projections (2071–2100).
    • fig. S4. As in fig. S3 but for intensity (°C) of severe heat wave.
    • fig. S5. Geographical settings and typical climatological conditions of the South Asian monsoon.
    • fig. S6. Spatial distribution of June-July-August 30-year (1982–2011) climatology of TW and TWmax (°C) for ERA-Interim and the MRCM simulations driven by ERA-Interim.
    • fig. S7. Spatial distribution of June-July-August 30-year climatology of TW and TWmax (°C) for ERA-Interim (1979–2008) and the MRCM ensemble of the three simulations (1976–2005) driven by three AOGCMs (CCSM4, MPI-ESM, and ACCESS).
    • fig. S8. Spatial distribution of 95th percentile exceedance of TWmax (days/year) from ERA-Interim (1979–2008) and the MRCM ensemble of simulations (1975–2005) driven by three AOGCMs (CCSM4, MPI-ESM, and ACCESS).
    • fig. S9. Histogram of TWmax (°C) at three stations (Punjab, Patna, and Lucknow) from in situ observations (1979–2008) and the MRCM simulations (1976–2005) driven by three AOGCMs (CCSM4, MPI-ESM, and ACCESS).
    • fig. S10. Histograms of daily maximum temperature, Tmax (°C), and maps of the ensemble averaged 30-year Tmax.
    • fig. S11. Bias-corrected annual Tmax return period for the most populous cities in the selected regions for each scenario.
    • fig. S12. Conversion tables between NOAA National Weather Service Heat Index and TW.
    • table S1. Horizontal resolution of the atmospheric and ocean components of the three AOGCMs used in this study.
    • References (45–47)

    Download PDF

    Files in this Data Supplement: