Lok Sabha Question No. 1823 (UNSTARRED), answered on 2023-12-13
Subject: Alarming increase in Aerosol Levels
Ministry: EARTH SCIENCES
Asked by: Sanjay Sadashivrao Mandlik, Prataprao  Jadhav, Sudheer Gupta, Sambhajirao Mane Dhairyasheel

- (a) Yes Sir.
- (b) The  study  by  the  Indian  Space  Research  Organization's  (ISRO)  Physical  Research Laboratory  using  the  ground-based  observations  of  aerosol  characteristics  including radiative  forcing  data  suggests  that  aerosol  levels  have  increased  specifically  over  the Indo-Gangetic Plain (IGP) and the Himalayan foothills and have implication which may lead to increased temperatures, altered rainfall patterns and accelerated melting of glacier ice and snow. The said study reports that the aerosol radiative forcing efficiency (ARFE) in  the  atmosphere  is  clearly  high  over  the  IGP  and  the  Himalayan  foothills  (80-135 Wm-2  per  unit  aerosol  optical  depth  (AOD)),  with  values  being  greater  at  higher elevations.  The aerosol-induced atmospheric warming and deposition of light-absorbing carbonaceous aerosols  on  snow  and  ice are  reported  to  be  the  primary  reasons  for  the current and future accelerated glacier and snow melt.

## GOVERNMENT OF INDIA MINISTRY OF EARTH SCIENCES LOK SABHA UNSTARRED QUESTION NO. 1823

## TO BE ANSWERED ON WEDNESDAY, 13 TH  DECEMBER, 2023

## ALARMING INCREASE IN AEROSOL LEVELS

## 1823. SHRI SANJAY SADASHIVRAO MANDLIK:

SHRI PRATAPRAO JADHAV:

SHRI SUDHEER GUPTA:

SHRI DHAIRYASHEEL SAMBAJIRAO MANE:

SHRI SHRIRANG APPA BARNE:

Will the Minister of EARTH SCIENCES be pleased to state:

- (a) whether  as  per  the  study  conducted  by  Indian  Space  Research  Organization's  (ISRO) Physical  Research  Laboratory,  Hindu  Kush-Himalaya-Tibetan  Plateau  region  has  been witnessing  an  alarming  increase  in  aerosol  levels  leading  to  increased  temperatures, altering rainfall patterns accelerating glacier retreat, etc.;
- (b) if so, the details thereof and the reasons for the same;
- (c) whether the study also shows that aerosols alone account for over 50 per cent of the total warming;
- (d) if so, the details thereof and the corrective measures taken by the Government to reduce flow of aerosols in the environment;
- (e) whether Hindu Kush-Himalaya-Tibetan Plateau  region having  largest  ice  mass  outside Antarctica are melting fast; and
- (f) if  so,  the  corrective  measures  taken/being  taken  by  the  Government  to  prevent  the melting of ice mass in the said region?

## ANSWER

## THE MINISTER OF EARTH SCIENCES (SHRI KIREN RIJIJU)

- (c) Yes  Sir.  It  has  been  reported  that  the  BC  aerosol  dominates  (≥75  %)  the  aerosol absorption over the Indo-Gangetic Plain including the Himalayas throughout the year and aerosols alone account for >50 % of the total warming of lower atmosphere.
- (d) India represents a unique case for aerosol loading, properties and their effects. Varying aerosol  sources  get  activated  at  different  spatial  and  temporal  scales.  This  changing nature of aerosols temporally and spatially when coupled with different land use nature across  India,  produces  a  very  complex  aerosol  radiation-cloud-precipitation-climate interaction. Over the years several institutes, universities and organizations in India have conducted  active  research  under  various  government  initiatives  towards  characterizing aerosol properties and their effects over the Indian region.
- (e) Yes  Sir.  The  Hindu  Kush-Himalaya-Tibetan  Plateau  region  consists  of  the  largest  ice mass outside the Polar regions. Several Indian institutes/universities/organizations funded by the Government of India through Ministry of Earth Sciences (MoES), Department of Science  &  Technology  (DST),  Ministry  of  Environment  Forest  and  Climate  Change (MoEF&CC), Department of Space (DoS), Ministry of Mines (MoM) and Ministry of Jal Shakti (MoJS) monitor Himalayan glaciers for various scientific studies including glacier melting and have reported accelerated  heterogeneous  mass loss  in  Himalayan  glaciers. The  mean  retreat  rate  of  Hindu  Kush  Himalayan  glaciers  is  14.9  ±  15.1  meter/annum (m/a); which varies from 12.7 ± 13.2 m/a in Indus, 15.5 ± 14.4 m/a in Ganga and 20.2 ± 19.7 m/a in Brahmaputra River basins. However, glaciers in the Karakoram region have shown  comparatively  minor  length  change  (-1.37  ±  22.8  m/a),  indicating  the  stable conditions.
- (f) The melting of glaciers is mostly a natural. The recession or melting of glaciers is also caused by global warming and climate change. Therefore, the rate of melting of glacier can't  be  prevented  or  slowed  down,  unless  all  the  factors  responsible  for  the  global warming and climate change can be controlled.

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