Nepalese monsoon June 2023

Nepal, home to 30 million inhabitants, is a country with diverse topography ranging from the low-lying plains in the south to the highest peaks in the Himalayas and the world. This provides for a range of different climatic zones, and therefore, potential climate risks, within the country. One of the most pronounced climate phenomena in Nepal is the South Asian monsoon, which starts each year around June and tends to peak in August.  

Monsoon rains have important societal impact, as drier years have negative implications for agriculture and water security, while wetter years can result in massive flooding. Nepal typically receives about 80% of its annual precipitation from the monsoon. However, the monsoon is becoming increasingly unreliable and difficult to predict due to climate change. This is especially the case during El Niño phases, during which the Eastern Pacific is warmer than average, and trade winds that draw moist air over the Indian subcontinent are weaker than usual. A strong El Niño phase is developing in June 2023, and Eastern Nepal has already been hit hard by heavy rains, flooding, and landslides, starting June 17, with 6 dead and 28 missing.  

Climate change is a major driver of increasing monsoon uncertainty and severity. 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. This amplified warming can alter the jet stream at mid latitudes, with potential downstream impacts on the South Asian monsoon. 

Changes in monsoon patterns make it difficult to forecast rains and adequately prepare for wetter or drier conditions. For example, just three weeks before the deadly flooding and landslides in Eastern Nepal, meteorologists predicted below-average monsoon rainfall. This indicates the urgency in developing adequate adaptation measures in Nepal, as well as reducing global emissions to slow climate change.  

Read more about extreme weather here.