India is heading for a drought, in meteorological terms, for the fourth time in the past 11 years. The previous droughts during this period were in 2002, 2004 and 2009.
A meteorological drought, in the sense that atmospheric scientists typically use the term, occurs when a monsoon ends with nationwide rainfall during the season falling below 90 per cent of the long-term average.
Such a string of droughts is not unprecedented. However, scientists have noticed some worrisome features in the monsoon in recent years. The question, inevitably, is whether human-induced factors driving climate change are involved, and whether they could affect rain in the coming years too.
There were five droughts between 1965 and 1975, and five more between 1979 and 1989, points out J. Srinivasan, who heads the Divecha Centre for Climate Change at the Indian Institute of Science in Bangalore. However, during the periods of 1965-1975 and 1979-1989, there were two ‘excess’ monsoon years when the nationwide rainfall quantum exceeded 110 per cent of the long-term average.
But there has not been a single excess-monsoon year since 1994. The balance between instances of drought and excess monsoon seems to have become skewed, he remarks.
“We are passing through a phase where the monsoon is tending to be on the negative side,” notes K. Krishna Kumar of the Indian Institute of Tropical Meteorology in Pune.
La Nina and El Nino
The monsoon has traditionally been sensitive to below-average temperatures in the tropical Pacific Ocean, known as La Nina, he points out. Such a cooling in the Pacific would usually produce copious rain over India and the monsoon would often end on the excess side. However, despite a La Nina that persisted for two years, the monsoons of 2010 and 2011 were only close to average. On the other hand, even a moderate El Nino can greatly retard the monsoon. “We need to understand what is holding the monsoon back and often pushing it to the negative side,” Dr. Krishna Kumar says.
Downward trend
There has been a downward trend in all-India monsoon rainfall since the late-1990s, observes Raghuram Murtugudde of the University of Maryland in the U.S. However, it is also important to bear in mind that the monsoon has cycles of high and low rainfall, and “it could be that we are in the middle of a low-rainfall cycle.” Even so, the severity of the last few droughts is unusual. “My worry is whether climate change is modulating and extending this long-term cycle [of low rainfall],” he told The Hindu.
Professor Murtugudde points to the steady and rapid warming of the Indian Ocean over at least the last 50 years. By reducing the land-ocean contrast, such warming could affect the monsoon. “We’ve to figure out what that means for the monsoon.”
In recent years, some high-profile research papers have pointed to fine particles in the atmosphere generated by human activity as having a major impact on the monsoon. These particles are borne in soot and in emissions by vehicles, thermal power stations and industrial plants. A paper published in Science last year by Massimo Bollasina of Princeton University, along with Yi Ming and V. Ramaswamy of the Geophysical Fluid Dynamics Laboratory in the U.S., came to the conclusion that such aerosols were weakening the monsoon over South Asia (see “Do aerosols have an impact on Indian monsoon?”, The Hindu, September 30, 2011).
However, S.K. Satheesh of the Centre for Atmospheric and Oceanic Sciences at the Indian Institute of Science, who works in this field, argues that more needs to be understood about the characteristics of aerosols found over India and their interaction with clouds before conclusions can be drawn about how these particles influence the monsoon.
Climate models
Climate models, which simulate the complex interactions over land, in the oceans and atmosphere, have grown in sophistication and become powerful tools. These models let scientists examine how factors like carbon dioxide build-up in the atmosphere, which produce global warming, and how aerosols can, individually and collectively, change climate.
Although these climate models predict global mean temperature well, they do poorly when it comes to the Indian monsoon and its variability, observes Professor Srinivasan. Some models show the monsoon increasing in strength as a result of climate change and others show the opposite.
“We know that climate change is going to affect the monsoon,” he says. “But there is still considerable uncertainty about just what’s going to happen, when and where.”
Keywords: Missing monsoon column, India monsoon, India drought
I would like to point to another research by Dutch scientist Marten Scheffer focusing on identifying the early-warning signals for climate that precede abrupt transitions related to patterns of climate that repeat themselves each year like the Indian monsoon. This study finds that dynamic systems like the Indian monsoon could suddenly shift gear and disappear altogether. While scientists are doing great work on trying to understand weather patterns and their likely trajectories, it does not take much intelligence to see how human activity is negatively impacting the environment around us. Over consumption of resources, the tons of garbage generated, drastic alterations of our eco-systems; especially by large infrastructure and developmental projects, all are causing irreversible change in the environmental cycles. In our quest to lead comfortable and long lives, we have entered a "chakravyuh" of change from which there seems to be no return but certain death of the species.
Large deviations of the Indian Summer monsoon rainfall is not unusual. IT happened in 1972, 1982, 2002 and perhaps now in 2012. But we have to wait till monsoon ends by September end to verify if this is true. You cannot conclude the result of a match, half way. Be patient. Wait for the end of the season.
Gopal Raj has interviewed eminent Indian earth Science Scientists. Has any of these big Scientist even said that monsoon this year will be even below normal ?. Can we depend of the other government Scientists like those of IMD and IITM, who have vested interest in the game ?, We have a wonderful perception that Indian Monsoon has to be connected with some thing Indian. Perhaps we have to correct our Indian Monsoon is a part of the Global Climate System. These Scientist seems to know much about El Nino and La Nino. Have they heard about Pacific Ocean Warm Pool and its shifts in certain years ? . They still live in era of tele-connections.
Any body can speculate about monsoon. They can attribute it Aerosol or even climate change. What is lacking is proof.
I am a retired CSIR Scientist.
"However, scientists have noticed some worrisome features in the
monsoon in recent years.The question,inevitably, is whether human-
induced factors driving climate change are involved, and whether
they could affect rain in the coming years too."The first sentence
who are the scientists? Blank. The second sentence implies that that
the worrisome fact is being explained. is it? The data quoted is
from 1965. (even assume it is from 1865) So what? Is not the time
frame too small - when one compares it with the fact that the earth
itself is very young and is constantly evolving / changing (5billion
years). While the Universe is barely 15 billion years. There is a
earthquake every five minutes somewhere in the world, a lighting
strike every two minutes. A mild volcano in a country can shut down
Europe's airport for days together. Why is man arrogating himself
that he can do damage to the extent that it can change climatic
conditions? It part of the politico-media-legal hype to make money.
IITM has published all-India rainfall for month-wise, season-wise and annual for the period 1871 to 1994 -- along with individual sub-division-wise. The data clearly show a cyclic variation of 60-year cycle following Astrological 60-year cycle. We have completed two 60-year cycles and we are in third cycle since 1987 and will complete by 2046. In the first cycle first 30 years refer to above the average part in which 7 years with more than 110% and in 2 years less than 90%. In the next 30 year below the average part they are 3 and 7. In the second cycle they are 5 & 2; 5 and 10; in the third cycle we are in better part of 30 years in which less than 90% is in 2002 and 2009. 2004 is above 90% and this year yet has to complete August and September. Let us wait and see. Don't give importance to poor research. Let IITM extend the data series beyond 1994.
It is correct that we should conclude that man-made factors are
responsible for drought.The population being high the usage is more
and so the water table will go down much more and therefore more
steps
should be taken and what are these steps?
1.More effluent treatment plants.
2.Rain Water harvesting in all places.
3.Check dams and weirs along all rivers.
4.Pollution from riverside industries to be totally blocked.
5.More desalination plants along the coast.
6.Landscaping in all cities so that more waterbodies are present
to store more water and prevent floods reaching residences.
Water is a precious requirement and we should take care of it for
our requirements to be met.
All nuclear powered countries are suffering from heavy droughts. 40% of France's
drinking water goes to cool nuclear plants which are also known to dehydrate the
atmosphere. Arnie Gundersen nuclear consultant with the NRC U.S.A clearly states that
nuclear power plants are 40% more thermally polluting than other modes of power
generation and also only at best 60% efficient as opposed to near 90 + efficiency of
other modes of power generation. Although we have only 20 smallMW operating plants
at present, our local temperature average is very high when compared to France and
England, (heavy nuclear power countries) both of which due to large number of nuclear
plants are suffering from HEAVY DROUGHTS with even farmer suicides in France.
During heat waves when there is no water, nuclear plants have to be shut down as they
rely heavily on water. That's the time electricity is needed most! So how can this be a
reliable base load form of electricity. France US shuts plants during the droughts!
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