Drought has resulted in millions of deaths in India over the years.[ citation needed ] Indian agriculture is heavily dependent on the country's climate: a favorable monsoon is critical to securing water for irrigating India's crops. In parts of India, failure of the monsoons causes water shortages, resulting in poor yields. [1] This is particularly true of major drought-prone regions southeastern Maharashtra, northern Karnataka, Andhra Pradesh, Odisha, Gujarat, Telangana, and Rajasthan.
Only about 35% of total agricultural land in India is irrigated and two-thirds of cultivated land is entirely dependent on rainfall. As such, the agricultural production system in the country is more vulnerable to damage from extreme climatic events, which causes increased water stress leading to inadequate water supplies for irrigation. Already, rises in average temperatures, changes in rainfall patterns, increasing frequency of extreme weather events, such as severe droughts and floods, and the shifting of agricultural seasons have been observed in different agro-ecological zones of India. Long drought spells during Kharif and increased temperatures and unseasonal heavy rains during the rabi season have caused serious distress to the farming communities in different states in recent years. Four major farming systems are prevailing in India: the irrigated system, rainfed system, silvo-pastoral system, and desert farming. [2]
In the past, droughts have periodically led to major Indian famines, including the Bengal famine of 1770, in which up to one third of the population in affected areas died; the 1876–1877 famine, in which over five million people died; and the 1899 famine, in which over 4.5 million died. [3] [4] In simple words, drought has destroyed India on a large scale. Eighteen meteorological and 16 hydrological droughts occurred in India between 1870 and 2018. The most severe meteorological droughts were in the years 1876, 1899, 1918, 1965, and 2000, while the five worst hydrological droughts occurred in the years 1876, 1899, 1918, 1965, and 2000. The drought of 1899 can be classified as meteorological as well as hydrological and was the most severe documented drought India has ever experienced to date.
Droughts correlate with heat waves (see List of Indian heat waves).
All such episodes of severe drought correlate with El Niño–Southern Oscillation (ENSO) events. [5] [6] El Niño-related droughts have also been implicated in periodic declines in Indian agricultural output. [7] Nevertheless, ENSO events that have coincided with abnormally high sea surfaces temperatures in the Indian Ocean—in one instance during 1997 and 1998 by up to 3 °C (5 °F)—have resulted in increased oceanic evaporation, resulting in unusually wet weather across India. Such anomalies occurred during a sustained warm spell that began in the 1990s. [8] A contrasting phenomenon is that, instead of the usual high-pressure air mass over the southern Indian Ocean, an ENSO-related oceanic low-pressure convergence center forms; it then continually pulls dry air from Central Asia, desiccating India during what should have been the humid summer monsoon season. This reversed airflow causes India's droughts. [9] The extent that an ENSO event raises sea surface temperatures in the central Pacific Ocean influences the degree of drought. [5] Around 43 percent of El Niño events are followed by drought in India. [10]
El Niño is the warm phase of the El Niño–Southern Oscillation (ENSO). It is associated with a band of warm ocean water that develops in the central and east-central equatorial Pacific, including the area off the west coast of South America. The ENSO is the cycle of warm and cold sea surface temperature (SST) of the tropical central and eastern Pacific Ocean.
A drought is a period of drier-than-normal conditions. A drought can last for days, months or years. Drought often has large impacts on the ecosystems and agriculture of affected regions, and causes harm to the local economy. Annual dry seasons in the tropics significantly increase the chances of a drought developing and subsequent wildfires. Periods of heat can significantly worsen drought conditions by hastening evaporation of water vapour, drying out forests and other vegetation and increasing fuel for wildfires.
Bangladesh is a densely populated, low-lying, mainly riverine country located in South Asia with a coastline of 580 km (360 mi) on the northern littoral of the Bay of Bengal. The delta plain of the Ganges (Padma), Brahmaputra (Jamuna), and Meghna Rivers and their tributaries occupy 79 percent of the country. Four uplifted blocks occupy 9 percent and steep hill ranges up to approximately 1,000 metres (3,300 ft) high occupy 12 percent in the southeast and in the northeast. Straddling the Tropic of Cancer, Bangladesh has a tropical monsoon climate characterised by heavy seasonal rainfall, high temperatures, and high humidity. Natural disasters such as floods and cyclones accompanied by storm surges periodically affect the country. Most of the country is intensively farmed, with rice the main crop, grown in three seasons. Rapid urbanisation is taking place with associated industrial and commercial development. Exports of garments and shrimp plus remittances from Bangladeshis working abroad provide the country's three main sources of foreign exchange income.
La Niña is an oceanic and atmospheric phenomenon that is the colder counterpart of El Niño, as part of the broader El Niño–Southern Oscillation (ENSO) climate pattern. The name La Niña originates from Spanish for "the girl", by analogy to El Niño, meaning "the boy". In the past, it was also called an anti-El Niño and El Viejo, meaning "the old man."
Climatology or climate science is the scientific study of Earth's climate, typically defined as weather conditions averaged over a period of at least 30 years. Climate concerns the atmospheric condition during an extended to indefinite period of time; weather is the condition of the atmosphere during a relative brief period of time. The main topics of research are the study of climate variability, mechanisms of climate changes and modern climate change. This topic of study is regarded as part of the atmospheric sciences and a subdivision of physical geography, which is one of the Earth sciences. Climatology includes some aspects of oceanography and biogeochemistry.
El Niño–Southern Oscillation (ENSO) is an irregular periodic variation in winds and sea surface temperatures over the tropical eastern Pacific Ocean, affecting the climate of much of the tropics and subtropics. The warming phase of the sea temperature is known as El Niño and the cooling phase as La Niña. The Southern Oscillation is the accompanying atmospheric component, coupled with the sea temperature change: El Niño is accompanied by high air surface pressure in the tropical western Pacific and La Niña with low air surface pressure there. The two periods last several months each and typically occur every few years with varying intensity per period.
The climate of India consists of a wide range of weather conditions across a vast geographic scale and varied topography. Based on the Köppen system, India hosts six major climatic sub types, ranging from arid deserts in the west, alpine tundra and glaciers in the north, and humid tropical regions supporting rain forests in the southwest and the island territories. Many regions have starkly different microclimates, making it one of the most climatically diverse countries in the world. The country's meteorological department follows the international standard of four seasons with some local adjustments: winter, summer, monsoon or rainy season, and a post-monsoon period.
The Walker circulation, also known as the Walker cell, is a conceptual model of the air flow in the tropics in the lower atmosphere (troposphere). According to this model, parcels of air follow a closed circulation in the zonal and vertical directions. This circulation, which is roughly consistent with observations, is caused by differences in heat distribution between ocean and land. It was discovered by Gilbert Walker. In addition to motions in the zonal and vertical direction the tropical atmosphere also has considerable motion in the meridional direction as part of, for example, the Hadley Circulation.
Drought in Australia is defined by the Australian Bureau of Meteorology as rainfall over period greater than three-months being in the lowest decile of what has been recorded for that region in the past. This definition takes into account that drought is a relative term and rainfall deficiencies need to be compared to typical rainfall patterns including seasonal variations. Specifically, drought in Australia is defined in relation to a rainfall deficiency of pastoral leases and is determined by decile analysis applied to a certain area. Note that this definition uses rainfall only because long-term records are widely available across most of Australia. However, it does not take into account other variables that might be important for establishing surface water balance, such as evaporation and condensation.
The characteristics of United States rainfall climatology differ significantly across the United States and those under United States sovereignty. Summer and early fall bring brief, but frequent thundershowers and tropical cyclones which create a wet summer and drier winter in the eastern Gulf and lower East Coast. During the winter, and spring, Pacific storm systems bring Hawaii and the western United States most of their precipitation. Low pressure systems moving up the East Coast and through the Great Lakes, bring cold season precipitation to from the Midwest to New England, as well as Great Salt Lake. The snow to liquid ratio across the contiguous United States averages 13:1, meaning 13 inches (330 mm) of snow melts down to 1 inch (25 mm) of water.
The Indian Ocean Dipole (IOD), also known as the Indian Niño, is an irregular oscillation of sea surface temperatures in which the western Indian Ocean becomes alternately warmer and then colder than the eastern part of the ocean.
Natural catastrophe in India, many of them related to the climate of India, cause massive losses of life and property. Droughts, flash floods, cyclones, avalanches, landslides brought by torrential rains, and snowstorms pose the greatest threats. A natural disaster might be caused by earthquakes, flooding, volcanic eruption, landslides, hurricanes etc. In order to be classified as a disaster, it will need to have a profound environmental effect and/or human loss and frequently incurs a financial loss. Other dangers include frequent summer dust storms, which usually track from north to south; they cause extensive property damage in North India and deposit large amounts of dust and dirt from arid regions. Hail is also common in parts of India, causing severe damage to standing crops such as rice and wheat and many more crops and effects many people.
The climate of Asia is dry across its southwestern region, with dry across much of the interior. Some of the largest daily temperature ranges on Earth occur in the western part of Asia. The monsoon circulation dominates across the southern and eastern regions, due to the Himalayas forcing the formation of a thermal low which draws in moisture during the summer. The southwestern region of the continent experiences low relief as a result of the subtropical high pressure belt; they are hot in summer, warm to cool in winter, and may snow at higher altitudes. Siberia is one of the coldest places in the Northern Hemisphere, and can act as a source of arctic air mass for North America. The most active place on Earth for tropical cyclone activity lies northeast of the Philippines and south of Japan, and the phase of the El Nino-Southern Oscillation modulates where in Asia landfall is more likely to occur. Many parts of Asia are being impacted by climate change.
The climate of Uttar Pradesh (U.P.) is primarily defined as humid subtropical with dry winter (Cwa) type with parts of Western U.P. as hot semi-arid (BSh) type. Alternatively, some authors refer to it as tropical monsoon. Variations do exist in different parts of the large state, however the uniformity of the vast Indo-Gangetic Plain forming bulk of the state gives a predominantly single climatic pattern to the state with minor regional variations. U.P. has a climate of extremes. With temperatures fluctuating anywhere from 0 °C or 32 °F to 50 °C or 122 °F in several parts of the state and cyclical droughts and floods due to unpredictable rains, the summers are extremely hot, winters are cold and the rainy season can be either very wet or very dry.
The Monsoon of South Asia is among several geographically distributed global monsoons. It affects the Indian subcontinent, where it is one of the oldest and most anticipated weather phenomena and an economically important pattern every year from June through September, but it is only partly understood and notoriously difficult to predict. Several theories have been proposed to explain the origin, process, strength, variability, distribution, and general vagaries of the monsoon, but understanding and predictability are still evolving.
The 1997–1998 El Niño was regarded as one of the most powerful El Niño–Southern Oscillation events in recorded history, resulting in widespread droughts, flooding and other natural disasters across the globe. It caused an estimated 16% of the world's reef systems to die, and temporarily warmed air temperature by 1.5 °C (2.7 °F) compared to the usual increase of 0.25 °C (0.45 °F) associated with El Niño events. The costs of the event were considerable, leading to global economic losses of US$5.7 trillion within five years.
The 2010–2012 La Niña event was one of the strongest on record. It caused Australia to experience its wettest September on record in 2010, and its second-wettest year on record in 2010. It also led to an unusual intensification of the Leeuwin Current, the 2010 Pakistan floods, the 2010–2011 Queensland floods, and the 2011 East Africa drought. It also helped keep the average global temperature below recent trends, leading to 2011 tying with 1997 for the 14th-warmest year on record. This La Niña event also led to above-average tropical cyclone activity in the North Atlantic Ocean during the 2010, 2011, and 2012 hurricane seasons, while the Eastern and Western Pacific experienced record low activity in 2010 and below average activity in 2011.
The 2014–2016 El Niño was a warming of the eastern equatorial Pacific Ocean that resulted in unusually warm waters developing between the coast of South America and the International Date Line. These unusually warm waters influenced the world's weather in a number of ways, which in turn significantly affected various parts of the world. These included drought conditions in Venezuela, Australia and a number of Pacific islands while significant flooding was also recorded. During the event, more tropical cyclones than normal occurred within the Pacific Ocean, while fewer than normal occurred in the Atlantic Ocean.
During 2014, tropical cyclones formed within seven different tropical cyclone basins, located within various parts of the Atlantic, Pacific and Indian Oceans. During the year, a total of 117 tropical cyclones had formed this year to date. 79 tropical cyclones had been named by either a Regional Specialized Meteorological Center (RSMC) or a Tropical Cyclone Warning Center (TCWC). The most active basin in 2014 was the Western Pacific, which documented 23 named systems, while the Eastern Pacific, despite only amounting to 22 named systems, was its basin's most active since 1992. Conversely, both the North Atlantic hurricane and North Indian Ocean cyclone seasons experienced the fewest cyclones reaching tropical storm intensity in recorded history, numbering 9 and 3, respectively. Activity across the southern hemisphere's three basins—South-West Indian, Australian, and South Pacific—was spread evenly, with each region recording seven named storms apiece. So far, 26 Category 3 tropical cyclones formed, including ten Category 5 tropical cyclones in the year, becoming as the third-most intense tropical cyclone activity on record, only behind with 1997 and 2018.
Effects of the El Niño–Southern Oscillation in Australia is present across most of Australia, particularly the north and the east, and is one of the main climate drivers of the country. Associated with seasonal abnormality in many areas in the world, Australia is one of the continents most affected and experiences extensive droughts alongside considerable wet periods that cause major floods. There exist three phases — El Niño, La Niña, and Neutral, which help to account for the different states of ENSO. Since 1900, there have been 28 El Niño and 19 La Niña events in Australia including the current 2023 El Niño event, which was declared on 17th of September in 2023. The events usually last for 9 to 12 months, but some can persist for two years, though the ENSO cycle generally operates over a time period from one to eight years.
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