Abstract The present study examines heatwave intensification across Vietnam under global warming levels (GWLs) of 1.5–4°C using high-resolution CMIP6-VN data from 20 downscaled models. Applying the excess heat factor methodology, we analyse four heatwave characteristics – intensity (HWI), duration (HWD), frequency (HWF), and peak temperature (HWP) – across seven sub-climate regions, validated against observations from 146 meteorological stations (1995–2014). Results reveal severe escalation with rising GWLs: HWI increases from 2.80°C2 to 4.25°C2, HWD from 13.6 to 118 days annually, HWF from 3.7 to 12.4 events, and HWP by 1.04°C nationally. Northern regions show greater intensity and frequency increases, while southern areas, especially R7, experience durations exceeding 160 days, highlighting stark regional disparities. Non-linear escalation beyond 3°C emerges with stronger model agreement (SNR > 1) at higher GWLs. These findings illustrate Vietnam’s acute vulnerability to heatwave extremes threatening agriculture, health, and infrastructure, emphasising urgent needs for region-specific adaptation strategies. With global temperatures reaching 1.55°C above pre-industrial levels in 2024, this research provides critical evidence for policymakers to strengthen climate resilience and support international efforts to limit warming. Research highlights <OrderedList> <ListItem> <ItemNumber>1.</ItemNumber> <ItemContent> Future heatwave characteristics across Vietnam were investigated using 20 climate models from the CMIP6-VN dataset. </ItemContent> </ListItem> <ListItem> <ItemNumber>2.</ItemNumber> <ItemContent> Changes in heatwave intensity (HWI), duration (HWD), frequency (HWF), and peak temperature (HWP) were evaluated at 1.5–4°C GWLs. </ItemContent> </ListItem> <ListItem> <ItemNumber>3.</ItemNumber> <ItemContent> The multi-model multi-scenario ensemble shows a nonlinear amplification of heatwave hazards, particularly beyond 3°C warming. </ItemContent> </ListItem> <ListItem> <ItemNumber>4.</ItemNumber> <ItemContent> Northern Vietnam exhibits the most severe increases in HWI and frequency, suggesting the growing on thermal stress in densely populated regions. </ItemContent> </ListItem> <ListItem> <ItemNumber>5.</ItemNumber> <ItemContent> Southern Vietnam may experience extremely long heatwave seasons, up to over 160 days over some areas, under high warming scenarios, indicating major risks to ecosystems, agriculture, and human health. </ItemContent> </ListItem> </OrderedList>

Regional patterns of heatwave intensification in Vietnam under global warming levels based on CMIP6 projections

期刊论文
发表日期：

2026年7月9日

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Quan Tran-Anh,
Ngoc Nguyen-Thi-Hong,
Wan Shafrina Wan Mohd Jaafar,
Nurul Asyiqin Abu Bakar,
Maggie Chel Gee Ooi

摘要

Abstract

The present study examines heatwave intensification across Vietnam under global warming levels (GWLs) of 1.5–4°C using high-resolution CMIP6-VN data from 20 downscaled models. Applying the excess heat factor methodology, we analyse four heatwave characteristics – intensity (HWI), duration (HWD), frequency (HWF), and peak temperature (HWP) – across seven sub-climate regions, validated against observations from 146 meteorological stations (1995–2014). Results reveal severe escalation with rising GWLs: HWI increases from 2.80°C² to 4.25°C², HWD from 13.6 to 118 days annually, HWF from 3.7 to 12.4 events, and HWP by 1.04°C nationally. Northern regions show greater intensity and frequency increases, while southern areas, especially R7, experience durations exceeding 160 days, highlighting stark regional disparities. Non-linear escalation beyond 3°C emerges with stronger model agreement (SNR > 1) at higher GWLs. These findings illustrate Vietnam’s acute vulnerability to heatwave extremes threatening agriculture, health, and infrastructure, emphasising urgent needs for region-specific adaptation strategies. With global temperatures reaching 1.55°C above pre-industrial levels in 2024, this research provides critical evidence for policymakers to strengthen climate resilience and support international efforts to limit warming.

Research highlights

Future heatwave characteristics across Vietnam were investigated using 20 climate models from the CMIP6-VN dataset.

Changes in heatwave intensity (HWI), duration (HWD), frequency (HWF), and peak temperature (HWP) were evaluated at 1.5–4°C GWLs.

The multi-model multi-scenario ensemble shows a nonlinear amplification of heatwave hazards, particularly beyond 3°C warming.

Northern Vietnam exhibits the most severe increases in HWI and frequency, suggesting the growing on thermal stress in densely populated regions.

Southern Vietnam may experience extremely long heatwave seasons, up to over 160 days over some areas, under high warming scenarios, indicating major risks to ecosystems, agriculture, and human health.