Weather

Cyclones

Odisha has experienced numerous cyclones since the 1960s, ranging from tropical cyclones to devastating super cyclones. Over the decades, significant changes in the region's climate have led to a noticeable increase in the frequency and intensity of tropical cyclones. This shift can be attributed to evolving weather patterns, likely influenced by factors such as global warming, rising sea surface temperatures, and changing monsoon dynamics. The heightened cyclone activity has not only posed recurrent challenges for disaster management but has also significantly impacted the livelihoods, infrastructure, and ecosystems of the region.

In past 64 years there were 11 cyclones. However, the frequency of cyclones have increased since the year 1995.

The probability of cyclones increased from 11.4% (1960-1995) to 24.1%(1995-2024)

Implications of cyclones on built form

The shifting weather patterns have also influenced changes in the materials and construction systems used in built forms. As extreme climatic events, such as cyclones, became more frequent and intense, people began transitioning from traditional mud houses to more resilient structures made of bricks and chira (laterite stone) walls. This shift reflects a conscious adaptation to withstand the harsh impacts of changing weather conditions, prioritizing durability and safety.

Winds

The Chilika lagoon area receives rainfall twice a year majority of which is received from the month of June to September which is brought by the South-West Monsoon wind. The average rainfall in the catchment is 1238.8 mm with 72 rainy days and from November to December is brought by North - East Retreating winds.

Precipitation

The chart shows the year-round rainfall pattern in the Chilika Lake region. The graph clearly indicates that there has been a shift in the rainy months since 2009. The rainy period has shifted from June-September to July-October.The monsoon season has become shorter and more unpredictable, with more hot and dry periods instead of the wet and humid weather it used to bring. Additionally, a trend can be observed where the overall rainfall is decreasing year by year. This change adversely affects farming activities in the area due to inconsistent rainfall.

Shift in the precipitation months

The graph shows the shift in the rainy months from june to october to july to august . July is the wettest month of the year where as increasingly the june month has seen reduction in rainfall and the october month has seen increase in rainfall. Due to this unpredictable nature of rain the farming of kharif crops has become difficult.

Implication of flood on structure

Due to the changing and unpredictable nature of rainfall in the Chilika lagoon area their has been change in the plinth level of the houses in the area as seen in the drawing which shows the increase in the plinth height. This has happened in response to the changing rainfall patterns . The higher plinths restrict the water movement into the house .

Temperature

The chart shows the year around temperature graph of the Chilika lagoon region from 1980 to 2023 and the colour below show the increase or decrease in the particular year in comparison to the mean temperature . The graph indicates that there is a rise in the mean temperature of the area which has resulted into increase in the cyclones in the area affecting livelihood of the fishermen .

Effects of temperature on fishes

The first drawing shows the various fish species that have been coming into Chilika Lake, including Khainga, Charuli, Kamuda, Tiger Prawns, Crabs, Jagela, Gaona, and Khurrata. However, due to climate change and rising temperatures, the water temperature in the lake is also increasing. It is estimated that the lake's water temperature is rising by 0.39°C every 10 years. This has affected the fish species in the lake, with several species like Charuli, Jagela, and Gaona either disappearing or struggling to thrive. This trend has been seen from year 2015 .

Shifts in Landform

Chilika is India’s largest brackish water lagoon, with a blend of marine, brackish and freshwater ecosystems. A key feature of Chilika is its inlets, which contribute to its lagoonal nature. A narrow mouth was discovered during the later stages of the Pleistocene period according to geological evidence in 1964.

These inlets are influenced by longshore currents and littoral drift from the Bay of Bengal. The longshore current moves sand along the coast and wave energy generated by winds results in waves striking the shore at an angle, causing sand movement from south to north.

Changes and shifts in inlets over the years:

1975 - Three inlets of the lake were created naturally due to sedimentation and coastal erosion, opening to the Bay of Bengal.
1986 - One opening was slightly displaced in the northward direction.
1990 - The mouth had shifted around 3 - 4 km northward.
2000 - A new inlet was dredged at Sipakuda village after the suggestion of scientists, having a width of 280m to decrease the freshwater in the lake.
2003 - The inlet near Motto Village was closed due to littoral drift.
2008 - A new mouth opened at Gabakunda village.
2019 - Four new mouths were formed after the Cyclone Fani.
2024 - At present, three inlets to the lake have shifted northward.

Major shifting of the mouth takes place from June to October, when freshwater flows from the lake to the ocean and northward littoral drift is high. This shift in landform has affected the ecosystems that exist along the lake.

The main impacts of opening the new sea mouth in 2000 were:

1) water depth reduction in the lagoon,

2) depletion of fish, shrimp, and crab, and

3) changes in fishing practices including an increase in aquaculture activities.

These inlets play an important role in controlling the lake’s seasonal changes, such as fluctuations in water levels and salinity, which impact agriculture and local livelihoods.

Shifts in Occupation & Livelihood

The changing weather patterns have significantly impacted the livelihoods of communities residing near the Chilika Lagoon. Natural factors such as frequent cyclones, rising temperatures, and other climate-related changes have disrupted traditional ways of life, forcing many to adapt and shift their occupations. The lagoon, once a rich source of sustenance through fishing and agriculture, has faced environmental stresses, including salinity fluctuations, loss of biodiversity, and damage to fishing infrastructure caused by extreme weather events. Consequently, many local inhabitants have been compelled to explore alternative means of earning a livelihood, such as engaging in tourism, small-scale trade, or seeking employment outside the region. These changes highlight the profound socio-economic implications of climate change on vulnerable communities.