Research ArticleENVIRONMENTAL SCIENCE

Increasing probability of mortality during Indian heat waves

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Science Advances  07 Jun 2017:
Vol. 3, no. 6, e1700066
DOI: 10.1126/sciadv.1700066
  • Fig. 1 Temperature and heat wave increases in India (1960–2009).

    Summer mean temperatures in India have increased from 1960 to 2009, as indicated by the MK trend test (A). The (B) accumulated heat wave intensity, (C) number of heat wave events, (D) heat wave duration, and (E) heat wave days during the latter period (1985–2009) has also increased over most areas of India relative to the previous period of 1960–1984.

  • Fig. 2 Standardized number of heat wave days, summer mean temperatures, and heat-related mortality.

    Standardized trends show the correspondence among the three variables. In years when heat wave days (yellow) and summer mean temperature (red) are above average, heat-related deaths also spike upward.

  • Fig. 3 Standardized population-weighted heat wave days, income-weighted heat wave days, and heat-related mortality.

    Standardized trends show the correspondence among the three variables. In most years when income-weighted heat waves (light green) and population-weighted heat waves (dark green) are above average, heat-related deaths also increase markedly.

  • Fig. 4 Probabilities of heat wave–caused mass mortality events.

    Parametric conditional probability density functions (PDFs) for yearly mortality given certain thresholds for summer mean temperatures (A) and heat wave days (B). With 0.5°C warmer mean temperatures or two more heat wave days per year, the probability of >100 heat-related deaths increase markedly. The relationship between the two variables and probability of mass mortality events is shown in (C).

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/3/6/e1700066/DC1

    fig. S1. Heat wave thresholds across India.

    fig. S2. Summer mean temperatures have increased substantially from 1960 to 2009.

    fig. S3. Mean heat wave characteristic value for two 25-year periods (1960–1984 and 1985–2009).

    fig. S4. Trend in the accumulated intensity, count, duration, and days of Indian heat waves’ distribution functions from 1960 to 2009 based on the MK trend test.

    fig. S5. Population and income spatial distribution in India and the number of heat wave days that occurred in 1973, 1983, 1984, and 1995.

    fig. S6. Results of a conditional probability density analysis of mortality given certain thresholds for summer maximum temperatures.

    fig. S7. CDDs have increased substantially from 1960 to 2009.

    table S1. Maximum likelihood and P values for mean summer mean temperature (MST mean)/mortality and heat wave days (HW days)/mortality for different copula families.

    table S2. Values of mortality, heat wave days, and summer mean temperatures.

  • Supplementary Materials

    This PDF file includes:

    • fig. S1. Heat wave thresholds across India.
    • fig. S2. Summer mean temperatures have increased substantially from 1960 to 2009.
    • fig. S3. Mean heat wave characteristic value for two 25-year periods (1960–1984 and 1985–2009).
    • fig. S4. Trend in the accumulated intensity, count, duration, and days of Indian heat waves’ distribution functions from 1960 to 2009 based on the MK trend test.
    • fig. S5. Population and income spatial distribution in India and the number of heat wave days that occurred in 1973, 1983, 1984, and 1995.
    • fig. S6. Results of a conditional probability density analysis of mortality given certain thresholds for summer maximum temperatures.
    • fig. S7. CDDs have increased substantially from 1960 to 2009.
    • table S1. Maximum likelihood and P values for mean summer mean temperature (MST mean)/mortality and heat wave days (HW days)/mortality for different copula families.
    • table S2. Values of mortality, heat wave days, and summer mean temperatures.

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