News Excerpt:
A study in Communications Earth & Environment reports a rise in concurrent heatwaves and extreme sea level rise at coastal locations between 1998 and 2017. These events may occur five times more often between 2025 and 2049 under a high emissions scenario.
Key points related to study on concurrent heatwave and extreme sea level’ (CHWESL):
- A so-called ‘concurrent heatwave and extreme sea level’ (CHWESL) event is when a heatwave and an extreme short-term sea level rise occur at the same coastal location over the same time period.
- This can pose a serious threat to coastal communities.
- Yet, there has so far been little research into the characteristics and occurrences of these events.
- According to The Hong Kong Polytechnic University, China, CHWESL events worldwide between 1979 and 2017 and projected future events between 2025 and 2049 under a high emissions climate scenario (the IPCC’s SSP5-8.5 scenario).
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- The authors only included events occurring in the extended summer season,
- Spanning May to September in the Northern Hemisphere,
- November to March in the Southern Hemisphere
- The authors only included events occurring in the extended summer season,
- Approximately 88% of the world's coastlines experienced a CHWESL event during the period 1979-2017.
- Around 39% of coastlines recorded a significant increase in the total duration of CHWESL conditions experienced over a year during 1998-2017 compared to 1979-1998, with tropical regions more likely to experience a greater increase.
- The authors also found that if current trends in carbon emissions continue unabated,
- CHWESL events could become up to five times more likely between 2025 and 2049.
- The authors also found that if current trends in carbon emissions continue unabated,
- There is a significant association between heat wave intensity and the probability of a CHWESL event occurring, with a 1% increase in heatwave intensity associated with an approximately 2% increase in the probability of a CHWESL event.
- Global coastal areas could experience on average 38 days of CHWESL conditions each year between 2025 and 2049,
- an increase of 31 days compared to the historical period of 1989-2013,
- according to projections under a high emissions climate scenario.
- CHWESL events could pose a significant threat to coastal communities, particularly from the risks of excess heat to human health.
- Countries in tropical areas, many of which are low or middle-income countries, are likely to be the most severely affected by CHWESL events and may struggle to cope with the effects.