Chennai floods December 2015

The study investigated the December 1, 2015, rainfall event in Chennai, where some stations recorded up to 494 mm of rain in 24 hours, causing an estimated US $3 billion in economic costs. Using observational data and regional climate models, researchers found no detectable effect of human-induced climate change on the probability of this extreme one-day rainfall. The analysis suggests that the cooling effect of aerosols in the western Bay of Bengal likely counteracted greenhouse gas warming, while non-anthropogenic factors, such as El Niño and sea surface temperature anomalies, played a more significant role.

• The rainfall event on December 1, 2015, was meteorologically extreme, with the highest recorded daily rainfall of 494 mm having a probability of occurrence in the current climate of between one in 600 and one in 2500 per year (95% confidence level).
• Analysis of observational data and SST-forced regional models indicates that human-caused emissions did not influence the extreme one-day rainfall in Chennai on December 1, 2015, for the periods 1900–1970 or 1970–2014.
• The lack of attribution to human-caused factors is likely due to the opposing effects of greenhouse gases and aerosols; specifically, air pollution (the 'brown cloud') has limited the increase of sea surface temperatures in the northern and western Bay of Bengal over the last 35 years.
• The flooding's impact was exacerbated by urban vulnerability and exposure, including unplanned growth, the presence of approximately 150,000 illegal buildings, encroachment of drainage channels, and a lack of timely desilting and flood zone planning.

APA

World Weather Attribution (2015). Chennai floods December 2015. https://www.worldweatherattribution.org/chennai-floods-december-2015/

Chicago

World Weather Attribution. Chennai floods December 2015. 2015. https://www.worldweatherattribution.org/chennai-floods-december-2015/.

Wikipedia

{{cite report |author=World Weather Attribution |title=Chennai floods December 2015 |date=1 December 2015 |url=https://www.worldweatherattribution.org/chennai-floods-december-2015/ |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{worldweatherattribution2015chennai, author = {{World Weather Attribution}}, title = {{Chennai floods December 2015}}, institution = {World Weather Attribution}, year = {2015}, month = dec, url = {https://www.worldweatherattribution.org/chennai-floods-december-2015/}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }