Global Warming is Weakening Sea Breeze, Threatens Urban Liveability: Report
The report says without these breezes, cities will face intensified urban heat stress, stagnant air quality, and a potential decline in wind power energy potential
Historical increase in sea-surface temperatures have already triggered a decline in sea-breeze days for 67% of the 18 coastal megacities
Visual Credits: Pixabay
A recent study by Nature warned that rising ocean temperatures are systematically weakening sea-land breeze, a natural circulation system that regulates temperature and air quality for the coastal cities and for more than 50% of the population that lives within 100 kms of coast where population is still rapidly growing.
The research also found that historical increase in sea-surface temperatures have already triggered a decline in sea-breeze days for 67% of the 18 coastal megacities, including London, Shanghai, and New York. These breezes act as a natural “air conditioner”, essential for mitigating urban heat islands and dispersing pollutants.
Declining Breeze Days
According to the research, the mid latitude cities, urban areas located between 30˚ and 60˚ north or south of the equator, are most vulnerable with New York, London, and Shanghai experiencing a decrease in breeze days between 29% and 45%. The research said the primary driver of this decline is shrinking sea-land temperature difference. As the ocean warms faster than coastal air, the thermal engine that pulls cool marine air inland is stalling.
The report projected that by 2050, the loss of breeze will be 4.5 times greater than under moderate emission-reduction pathways. This weakening of these coastal winds poses a direct threat to Sustainable Development Goals 11 about sustainable cities and Goal 13 about climate action. Without these breezes, cities also face intensified urban heat stress, stagnant air quality, and a potential decline in wind power energy potential.
In India, the study categorised Mumbai as a low impact region, with only experiencing a slight 3% decrease in breeze days because ocean warming near Mumbai has been relatively modest compared to the warming seen in higher latitudes. Despite a relatively stable coastal circulation, the research warned that these tropical regions still face other significant risks from warming oceans, such as more intense typhoons and extreme rainfall events.
Way Forward
The report concluded that while urban planning such as preserving ventilation corridors and designing building shapes to channel remaining sea breezes into urban centers may help but the researchers point out that it may not be enough as local planning cannot stop the rising ocean temperature. The only permanent solution is aggressive global climate action to slow ocean warming