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CHWESL events: When sea levels rise in response to heatwaves

Recent research reveals a concerning escalation in the simultaneous occurrence of heatwaves and extreme sea level rises along coastlines worldwide. This phenomenon, known as Concurrent Heat Wave and Extreme Sea Level (CHWESL) events, has experienced a significant uptick in frequency between 1998 and 2017.

This increase is highly notable when compared to the preceding two decades. A recent study detailed in Communications Earth & Environment highlights this alarming trend and includes projections that suggest an even more drastic increase under future high emissions scenarios.

Tracking the tide and temperature

Shuo Wang and Mo Zhou conducted the research, focusing on CHWESL events from 1979 through 2017. They also projected future occurrences from 2025 to 2049, using the Intergovernmental Panel on Climate Change’s high emissions pathway, the SSP5-8.5 scenario.

Their analysis shows that CHWESL events have already affected roughly 88% of the world’s coastlines during the study period.

Additionally, about 39% of these coastlines have experienced a noticeable increase in the frequency and duration of these events over the last two decades. Tropical regions have suffered most from this escalation.

The researchers found a strong correlation between the intensity of heatwaves and the increased likelihood of concurrent sea level rises.

Specifically, a 1% increase in heat wave intensity leads to a 2% increase in the likelihood of a CHWESL event occurring.

Escalating CHWESL events and their impacts

Looking ahead, the study forecasts that global coastal areas might endure, on average, 38 days of CHWESL conditions each year. This projection covers the period between 2025 and 2049.

Consequently, this represents a staggering increase of 31 days compared to the historical period of 1989–2013.

Such a surge in CHWESL events poses severe risks. The intensified heat directly impacts human health, and heightened sea levels compound these effects.

Strengthening resilience against climatic threats

“The significant rise in both the occurrence and intensity of these events, especially in tropical areas, calls for an urgent need to develop robust risk mitigation strategies,” explained Shuo Wang.

“Countries, particularly those with low to middle incomes in these regions, are likely to face severe challenges in coping with these dual threats,” he adds.

Mo Zhou further emphasized the importance of preparedness. He stated, “It is crucial that we prioritize and refine our strategies for dealing with these events. Developing comprehensive risk mitigation plans is imperative for enhancing resilience against future CHWESL occurrences.”

Global collaboration to combat CHWESL events

The findings from Wang and Zhou’s study serve as a crucial call to action for policymakers, researchers, and community leaders globally.

Furthermore, as the planet warms and sea levels rise, experts project that the frequency and severity of CHWESL events will increase.

This trend underscores the urgent need for proactive approaches in climate adaptation and disaster preparedness.

Consequently, the intersection of intensifying heatwaves and rising sea levels presents a formidable challenge to coastal communities worldwide.

Therefore, addressing this dual hazard requires a concerted effort to integrate scientific research with effective policy and community engagement.

Such collaboration ensures that all nations, especially the most vulnerable, are equipped to manage and mitigate the risks of future CHWESL events.

The full study was published in the journal Communications Earth & Environment.


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