Climate Change (Input 2) - Insights from a recent paper : 'Anthropogenic footprint of climate change in the June 2013 Northern India flood'

 Synopsis of the Report :-

1. During 13 –17 June 2013, heavy rainfall occurred in the northern Indian state of Uttarakhand and led to one of the worst floods and landslides in history, resulting in more than 5000 casualties and a huge loss of property. This event also affected other parts of India including Himachal Pradesh, Haryana, Delhi and Uttar Pradesh, as well as western Nepal and parts of Tibet.

2. In a study by scientists, meteorological and climatic conditions leading up to this rainfall event in 2013 and similar cases were analyzed for the period of 1979–2012.

• Using complex meteorological models to study natural and anthropogenic influences as well as the role of the long-term climate trends on rainfall in the region it was found that:-  Northern India has experienced increasingly large rainfall in June since the late 1980s.
•  The increase in rainfall appears to be associated with a tendency in the upper troposphere towards amplified short waves.
•  The phasing of such amplified short waves is tied to increased loading of green-house gases and aerosols.
•  In June2013, 60–90 % of the rainfall amount was attributed to post-1980 climate trends with another study revealing that though this rainfall was at least a century scale event, the probability for such an incident recurring has increased in the present climate compared to that of pre-industrial times.

3. The study also found that such heavy rainfall and widespread flood events have become increasingly frequent in northern South Asia :-

•  In July2010, an extreme rainfall event in northern Pakistan resulted in floods that killed about 3000 and affected around 20 million people.

• More recently (2–6 September 2014), some regions in India (Jammu and Kashmir) and Pakistan (Azad Kashmir, Gilgit-Baltistan and Punjab) suffered extreme floods caused by heavy rainfall which killed more than 500 people.

4. The study found that increased levels of greenhouse gases and aerosols in the post-1980 period have caused changes in the upper troposphere and that as a result of anthropogenic climate change, the circulation structure has been modified in such a way that it significantly aggravates rainstorm occurrences in northern South Asia, hence increasing the severity of floods.
5. Also, the occurrence of this June 2013 event during pre-monsoon season in northern South Asia, along with the circulation and precipitation trends in June, calls for the adaptation of risk management strategies in the face of increasingly frequent and strong rainstorms outside the core monsoon months (July–August). Adaptation measures such as developing strategies and policies for flood management in the face of climate-related extreme events are urged.
6. In addition, the amplified upper-level stationary waves and associated dynamics, as revealed in this study, will need to be represented accurately in the forecasting tools revealed in the post-1980 trends is attributed.

The full paper is available here
For animation of the cloud movements of the 'Uttarakhand Cloudburst' see here

" It appears that the increase in aerosols due to pollution, combined with changes in the jet stream due to increasing greenhouse gases, have made June events like the 2013 flood more likely to occur since 1988."
- Jeff Masters, Director of Meteorology, wunderground.com

Praful Rao,
Kalimpong,
Dist Darjeeling

Rainfall data Darjeeling district and N Sikkim - Jun2013

Jun2013 was extraordinary; it was the month of the "Himalayan Tsunami" when torrential rains over Uttarakhand and Himachal Pradesh in mid Jun2013, caused unprecedented loss of life and a disaster which the country is still trying to grapple with.
Whilst the rest of the country reported normal to excess rainfall, the north eastern states of India went deficient in rainfall. STH reported the formation of two low pressure areas in the Bay of Bengal, the first weather system eventually reaching the Uttarakhand region in mid Jun2013.
Also, two interesting facts observed in Jun2013 were :-

• The 24hr rainfall over Dehradun on 17Jun2013 (338mm) was more than the entire month's rainfall in Kalimpong for Jun2013.
• In the Darjeeling -Sikkim area, approximately half the month of June2013 was almost dry (less than 5mm rainfall).
  
  
  Praful Rao,
  Kalimpong,
  Dist Darjeeling.
  
  
  
  

Darjeeling & Sikkim - queuing up for the next 'Himalayan Tsunami'

Do you notice the uncanny similarity between images of the 'Himalayan Tsunami' of mid-Jun2013 (placed on the LHS) and those from the Darjeeling - Sikkim Himalaya (on RHS)?

Here are 10 reasons why the Darjeeling - Sikkim Himalaya could also suffer the same fate as Uttarakhand :-
           

• Our geographical location on the southern most part of the Himalayan arc is unique. As such the Darjeeling – Sikkim Himalaya is situated barely 800km north of the Bay of Bengal, which brews up 5-7 cyclones or depressions annually.
• Due to our location, our average annual rainfall is approx 3000mm, double that of Uttarakhand (1523mm) and 3 X the national average.
• Rainfall pattern has shown a perceptible change in the recent past – extremes in rainfall being more the norm than an exception (In May2013 we had double the monthly rainfall but Jun2013 has been largely dry till date)
• We have a long history of landslide disasters viz Sep 1899, Jun 1950, Oct 1968, Sep 2007, Cyclone AILA in May 2009 and 18Sep2011 (earthquake induced).
• Geological Survey of India (or GSI, the nodal Govt. body looking after landslides in India) categorizes our area as amongst the most landslide prone in the country.
• In the recent past, there has been phenomenal developmental activity much of which has been unplanned and haphazard, paying scant heed to building codes etc.
  More than 30 dams have been constructed or are planned in the Teesta river basin.
  Also the tremendous rural to urban migration has resulted in our major towns showing signs of severe distress with basic civic facilities such as potable water, public latrines, solid waste management and most importantly, drainage being on the verge of collapse. Densely populated colonies have sprung up on unstable and unsafe slopes.
  Non-engineered roads constructed on a massive scale all over the region by poorly trained or unemployed petty contractors will be a major cause of landslides in the future.
• Both Darjeeling and Sikkim have large scale influx of tourists, many more than the pilgrims who were caught up in the Uttarakhand disaster.
• Densely populated settlements and towns such as Rangpo, Singtam, Majitar, Melli, Jorethang have comeup along banks of rivers ie Teesta and Rangit.
• As population increases, forest cover has reduced all over the region
• Even after the earthquake of 18Sep2011, disaster management has received little priority in this region.

Photo credits of Darjeeling/Sikkim :
Kundan Yolmo, Sikkim Express, Das Studio (Darjeeling)
Photos from Uttarakhand obtained from the internet.

Praful Rao,
Kalimpong,
Darjeeling District.