Bangladesh, Cambodia, Vietnam (monsoon July/August 2023)

As monsoon season has arrived, countries like Bangladesh, Cambodia and Vietnam have been experiencing heavy and prolonged rainfall, leading to devastating landslides and floods.

Climate change is a major driver of increasing monsoon uncertainty. This is because the monsoon forms based on heat differentials between the South Asian landmass and the surrounding oceans. The atmospheric circulation patterns that have historically contributed to a consistent monsoon are now being disrupted by rapid global warming. One reason for this disruption is that not all regions of the globe are warming at the same rate: the Arctic is warming at a rate four times faster than the global average. Due in part to rapidly declining Arctic sea ice cover, the Arctic is experiencing a positive feedback loop by which less sunlight is reflected by ice and warming therefore accelerates.  Research into a past warm period in Earth’s history suggests that continued climate warming is linked to more intense precipitation over South Asia and that lower Arctic sea ice extent leads to a stronger South Asian monsoon, therefore similar mechanisms may be at play presently. 

Bangladesh

In Bangladesh, the southeastern region received 342 milimeters of rain on August 7th, which was the highest amount since 1988. Officials reported that monsoon rains and subsequent flooding in southeast Bangladesh have affected at least 1.2 million people. According to Oxfam nearly 300,000 people in Cox’s Bazar have been impacted, with thousands having been displaced. In Bandarban (Chattogram region), around 30.000 people were stranded, with hundreds losing their homes due to landslides. 

Vietnam 

Vietnam is also experiencing heavier rainfall than normal, with many areas reporting record rainfall and experiencing higher volumes of rain than average. Rainfall levels in both the southwest and southeast regions have surpassed those of the same period last year, with increases ranging from 50% to 130%. Notably, the Soc Trang Province has seen an astonishing 247% increase. Meanwhile, in the Central Highlands, rainfall has risen by 60-70%. The heavy rainfall has been triggering floods and landslides, having already led to heavy damage and dozens of deaths. From August 2nd to 7th, these extreme events resulted in the damage of 351 houses and 176 hectares of rice fields and other crops in North Vietnam.  

Cambodia

As climate change takes hold, Cambodians are also seeing changes such as higher temperatures, a less predictable monsoon and increasing floods and droughts. At the beginning of July, the capital of Cambodia, Phnom Penh, experienced the most intense rainfall in the past three years, resulting in flash floods that submerged several streets and roads. On August 2nd, widespread flooding hit nine Cambodian provinces, impacting residential areas, infrastructure, and rice crops. Nearly 7,000 homes housing over 7,000 families and more than 10,000 hectares of rice fields were affected. As the monsoon season continues, the risk to public health by vector-borne diseases, such as dengue fever, also grows stronger. Stagnant water following heavy rainfall and flooding is the biggest contributor to increased transmission of mosquito-borne disease. According to the Ministry of Health, Cambodia has seen 4,668 cases of dengue fever and 10 deaths in the past six months. These figures indicate a worrisome surge, almost doubling last year’s numbers. As the monsoon season persists, maintaining vigilance against the threat of dengue fever has become increasingly important. 

Read more about extreme weather here.

Read more about health risks related to climate change here.