El Nino Enhances Exposure to Humid Heat Extremes

Outcome/Accomplishment

Humid heat extremes, characterized by high wet bulb temperature (Tw), pose health risks even to young, healthy individuals. While strong El Niño events are known to affect extreme Tw days, the impact of different El Niño types (Central Pacific and Eastern Pacific) has not been well studied. Using historical data and future climate projections, atmospheric scientists at the University of Hawaiʻi at Mānoa (UH-M) examined how these El Niño types affect the frequency and spatial extent of dangerous Tw. UH-M is a partner institution of the NSF-funded Engineering Research Center (ERC) for Environmentally Applied Technology Hub (EARTH), headquartered at the University of Kansas.

Impact/Benefits

The researchers found that under future warming, Eastern Pacific and Central Pacific El Niño events drive distinctly different, regionally varying patterns of dangerous Tw, yet both significantly increase the affected population and area impacted by humid heat extremes at all global warming levels. Even at low global warming levels, during El Niño events, the population exposed to dangerous Tw is expected to be equal to that exposed regularly when the mean warming is more than four times higher. This highlights the need to consider El Niño diversity in assessing the additional heat stress in heavily populated regions as the planet warms and approaches the critical threshold of heat stress.

Explanation/Background

Using a 12-member CMIP6 ensemble at discrete global warming targets (+1.5, 2, 3, 4°C), this study shows progressively enhanced humid heat extent during EP events primarily in Mainland Southeast Asia, while South Asia experiences regionally opposing effects from EP and CP events. EP and CP events drive distinctly different, regionally varying patterns of dangerous Tw, yet both significantly increase the affected population and area impacted by humid heat extremes at all global warming levels. This amplification surpasses the impact of an additional degree of global warming, highlighting El Niño's compounding effect on heat stress threats across warmer climates.

Image
Credit:
University of Hawaiʻi

Location

Lawrence, KS

e-mail

Start Year

Energy and Sustainability

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Energy and Smart Infrastructure

Lead Institution

The University of Kansas

Core Partners

Lehigh University, University of Hawaii, University of Maryland, University of Notre Dame, University of South Dakota

Fact Sheet

Image
Credit:
University of Hawaiʻi

Outcome/Accomplishment

Humid heat extremes, characterized by high wet bulb temperature (Tw), pose health risks even to young, healthy individuals. While strong El Niño events are known to affect extreme Tw days, the impact of different El Niño types (Central Pacific and Eastern Pacific) has not been well studied. Using historical data and future climate projections, atmospheric scientists at the University of Hawaiʻi at Mānoa (UH-M) examined how these El Niño types affect the frequency and spatial extent of dangerous Tw. UH-M is a partner institution of the NSF-funded Engineering Research Center (ERC) for Environmentally Applied Technology Hub (EARTH), headquartered at the University of Kansas.

Location

Lawrence, KS

e-mail

Start Year

Energy and Sustainability

Energy and Sustainability Icon
Energy and Sustainability Icon

Energy and Smart Infrastructure

Lead Institution

The University of Kansas

Core Partners

Lehigh University, University of Hawaii, University of Maryland, University of Notre Dame, University of South Dakota

Fact Sheet

Impact/benefits

The researchers found that under future warming, Eastern Pacific and Central Pacific El Niño events drive distinctly different, regionally varying patterns of dangerous Tw, yet both significantly increase the affected population and area impacted by humid heat extremes at all global warming levels. Even at low global warming levels, during El Niño events, the population exposed to dangerous Tw is expected to be equal to that exposed regularly when the mean warming is more than four times higher. This highlights the need to consider El Niño diversity in assessing the additional heat stress in heavily populated regions as the planet warms and approaches the critical threshold of heat stress.

Explanation/Background

Using a 12-member CMIP6 ensemble at discrete global warming targets (+1.5, 2, 3, 4°C), this study shows progressively enhanced humid heat extent during EP events primarily in Mainland Southeast Asia, while South Asia experiences regionally opposing effects from EP and CP events. EP and CP events drive distinctly different, regionally varying patterns of dangerous Tw, yet both significantly increase the affected population and area impacted by humid heat extremes at all global warming levels. This amplification surpasses the impact of an additional degree of global warming, highlighting El Niño's compounding effect on heat stress threats across warmer climates.