Influence of internal variability on population exposure to hydroclimatic changes

Justin S. Mankin, Daniel Viviroli, Mesfin Mekonnen, Arjen Ysbert Hoekstra, Radley M. Horton, Jason E. Smerdon, Noah S. Diggenbaugh

    Research output: Contribution to journalArticleAcademicpeer-review

    9 Citations (Scopus)
    66 Downloads (Pure)

    Abstract

    Future freshwater supply, human water demand, and people's exposure to water stress are subject to multiple sources of uncertainty, including unknown future pathways of fossil fuel and water consumption, and 'irreducible' uncertainty arising from internal climate system variability. Such internal variability can conceal forced hydroclimatic changes on multi-decadal timescales and near-continental spatial-scales. Using three projections of population growth, a large ensemble from a single Earth system model, and assuming stationary per capita water consumption, we quantify the likelihoods of future population exposure to increased hydroclimatic deficits, which we define as the average duration and magnitude by which evapotranspiration exceeds precipitation in a basin. We calculate that by 2060, backsim31%–35% of the global population will be exposed to >50% probability of hydroclimatic deficit increases that exceed existing hydrological storage, with up to 9% of people exposed to >90% probability. However, internal variability, which is an irreducible uncertainty in climate model predictions that is under-sampled in water resource projections, creates substantial uncertainty in predicted exposure: backsim86%–91% of people will reside where irreducible uncertainty spans the potential for both increases and decreases in sub-annual water deficits. In one population scenario, changes in exposure to large hydroclimate deficits vary from −3% to +6% of global population, a range arising entirely from internal variability. The uncertainty in risk arising from irreducible uncertainty in the precise pattern of hydroclimatic change, which is typically conflated with other uncertainties in projections, is critical for climate risk management that seeks to optimize adaptations that are robust to the full set of potential real-world outcomes.
    Original languageEnglish
    Article number044007
    Pages (from-to)-
    JournalEnvironmental research letters
    Volume12
    Issue number4
    DOIs
    Publication statusPublished - 2017

    Fingerprint

    Uncertainty
    Population
    Climate
    fuel consumption
    climate
    Water
    water demand
    water stress
    Drinking
    fossil fuel
    evapotranspiration
    population growth
    climate modeling
    water resource
    Fossil Fuels
    timescale
    Water Resources
    Climate models
    Evapotranspiration
    exposure

    Keywords

    • METIS-322158

    Cite this

    Mankin, J. S., Viviroli, D., Mekonnen, M., Hoekstra, A. Y., Horton, R. M., Smerdon, J. E., & Diggenbaugh, N. S. (2017). Influence of internal variability on population exposure to hydroclimatic changes. Environmental research letters, 12(4), -. [044007]. https://doi.org/10.1088/1748-9326/aa5efc
    Mankin, Justin S. ; Viviroli, Daniel ; Mekonnen, Mesfin ; Hoekstra, Arjen Ysbert ; Horton, Radley M. ; Smerdon, Jason E. ; Diggenbaugh, Noah S. / Influence of internal variability on population exposure to hydroclimatic changes. In: Environmental research letters. 2017 ; Vol. 12, No. 4. pp. -.
    @article{72ca244dce34488a9c3cffbd57362095,
    title = "Influence of internal variability on population exposure to hydroclimatic changes",
    abstract = "Future freshwater supply, human water demand, and people's exposure to water stress are subject to multiple sources of uncertainty, including unknown future pathways of fossil fuel and water consumption, and 'irreducible' uncertainty arising from internal climate system variability. Such internal variability can conceal forced hydroclimatic changes on multi-decadal timescales and near-continental spatial-scales. Using three projections of population growth, a large ensemble from a single Earth system model, and assuming stationary per capita water consumption, we quantify the likelihoods of future population exposure to increased hydroclimatic deficits, which we define as the average duration and magnitude by which evapotranspiration exceeds precipitation in a basin. We calculate that by 2060, backsim31{\%}–35{\%} of the global population will be exposed to >50{\%} probability of hydroclimatic deficit increases that exceed existing hydrological storage, with up to 9{\%} of people exposed to >90{\%} probability. However, internal variability, which is an irreducible uncertainty in climate model predictions that is under-sampled in water resource projections, creates substantial uncertainty in predicted exposure: backsim86{\%}–91{\%} of people will reside where irreducible uncertainty spans the potential for both increases and decreases in sub-annual water deficits. In one population scenario, changes in exposure to large hydroclimate deficits vary from −3{\%} to +6{\%} of global population, a range arising entirely from internal variability. The uncertainty in risk arising from irreducible uncertainty in the precise pattern of hydroclimatic change, which is typically conflated with other uncertainties in projections, is critical for climate risk management that seeks to optimize adaptations that are robust to the full set of potential real-world outcomes.",
    keywords = "METIS-322158",
    author = "Mankin, {Justin S.} and Daniel Viviroli and Mesfin Mekonnen and Hoekstra, {Arjen Ysbert} and Horton, {Radley M.} and Smerdon, {Jason E.} and Diggenbaugh, {Noah S.}",
    year = "2017",
    doi = "10.1088/1748-9326/aa5efc",
    language = "English",
    volume = "12",
    pages = "--",
    journal = "Environmental research letters",
    issn = "1748-9318",
    publisher = "IOP Publishing Ltd.",
    number = "4",

    }

    Mankin, JS, Viviroli, D, Mekonnen, M, Hoekstra, AY, Horton, RM, Smerdon, JE & Diggenbaugh, NS 2017, 'Influence of internal variability on population exposure to hydroclimatic changes', Environmental research letters, vol. 12, no. 4, 044007, pp. -. https://doi.org/10.1088/1748-9326/aa5efc

    Influence of internal variability on population exposure to hydroclimatic changes. / Mankin, Justin S.; Viviroli, Daniel; Mekonnen, Mesfin; Hoekstra, Arjen Ysbert; Horton, Radley M.; Smerdon, Jason E.; Diggenbaugh, Noah S.

    In: Environmental research letters, Vol. 12, No. 4, 044007, 2017, p. -.

    Research output: Contribution to journalArticleAcademicpeer-review

    TY - JOUR

    T1 - Influence of internal variability on population exposure to hydroclimatic changes

    AU - Mankin, Justin S.

    AU - Viviroli, Daniel

    AU - Mekonnen, Mesfin

    AU - Hoekstra, Arjen Ysbert

    AU - Horton, Radley M.

    AU - Smerdon, Jason E.

    AU - Diggenbaugh, Noah S.

    PY - 2017

    Y1 - 2017

    N2 - Future freshwater supply, human water demand, and people's exposure to water stress are subject to multiple sources of uncertainty, including unknown future pathways of fossil fuel and water consumption, and 'irreducible' uncertainty arising from internal climate system variability. Such internal variability can conceal forced hydroclimatic changes on multi-decadal timescales and near-continental spatial-scales. Using three projections of population growth, a large ensemble from a single Earth system model, and assuming stationary per capita water consumption, we quantify the likelihoods of future population exposure to increased hydroclimatic deficits, which we define as the average duration and magnitude by which evapotranspiration exceeds precipitation in a basin. We calculate that by 2060, backsim31%–35% of the global population will be exposed to >50% probability of hydroclimatic deficit increases that exceed existing hydrological storage, with up to 9% of people exposed to >90% probability. However, internal variability, which is an irreducible uncertainty in climate model predictions that is under-sampled in water resource projections, creates substantial uncertainty in predicted exposure: backsim86%–91% of people will reside where irreducible uncertainty spans the potential for both increases and decreases in sub-annual water deficits. In one population scenario, changes in exposure to large hydroclimate deficits vary from −3% to +6% of global population, a range arising entirely from internal variability. The uncertainty in risk arising from irreducible uncertainty in the precise pattern of hydroclimatic change, which is typically conflated with other uncertainties in projections, is critical for climate risk management that seeks to optimize adaptations that are robust to the full set of potential real-world outcomes.

    AB - Future freshwater supply, human water demand, and people's exposure to water stress are subject to multiple sources of uncertainty, including unknown future pathways of fossil fuel and water consumption, and 'irreducible' uncertainty arising from internal climate system variability. Such internal variability can conceal forced hydroclimatic changes on multi-decadal timescales and near-continental spatial-scales. Using three projections of population growth, a large ensemble from a single Earth system model, and assuming stationary per capita water consumption, we quantify the likelihoods of future population exposure to increased hydroclimatic deficits, which we define as the average duration and magnitude by which evapotranspiration exceeds precipitation in a basin. We calculate that by 2060, backsim31%–35% of the global population will be exposed to >50% probability of hydroclimatic deficit increases that exceed existing hydrological storage, with up to 9% of people exposed to >90% probability. However, internal variability, which is an irreducible uncertainty in climate model predictions that is under-sampled in water resource projections, creates substantial uncertainty in predicted exposure: backsim86%–91% of people will reside where irreducible uncertainty spans the potential for both increases and decreases in sub-annual water deficits. In one population scenario, changes in exposure to large hydroclimate deficits vary from −3% to +6% of global population, a range arising entirely from internal variability. The uncertainty in risk arising from irreducible uncertainty in the precise pattern of hydroclimatic change, which is typically conflated with other uncertainties in projections, is critical for climate risk management that seeks to optimize adaptations that are robust to the full set of potential real-world outcomes.

    KW - METIS-322158

    U2 - 10.1088/1748-9326/aa5efc

    DO - 10.1088/1748-9326/aa5efc

    M3 - Article

    VL - 12

    SP - -

    JO - Environmental research letters

    JF - Environmental research letters

    SN - 1748-9318

    IS - 4

    M1 - 044007

    ER -