India is experiencing yet another erratic monsoon as the South West monsoons appear to have come to a halt in peninsular India. After two weeks of normal monsoons, the second week of July proved to be a relatively dry spell for the southern states of Karnataka, Kerala, Madhya Pradesh and Maharashtra, even as heavy floods were witnessed in the Northeast. In 2016, the monsoons were late by around a fortnight.

Although the stark changes in Indian monsoon — both south-western and north-eastern — are manifesting their effects on the annual rainfall, affecting a plethora of flora and fauna and the agricultural economy, thus leading to failed crops, droughts and floods, the correlation between climate change and monsoon patterns is multifaceted and requires a detailed look.

Past records and statistics show that India has been experiencing delayed south-west monsoon along the Western Ghats, the northern states of Rajasthan and Punjab and the central state of Maharashtra for four years in a row. This delay in monsoons has been accompanied by rising temperatures in the subcontinent, which shot up to the highest recorded in 2016. The temperature over the Indian Ocean has also steadily increased by an average of 1.2-degree centigrade, which is alarmingly higher than the global average surface water warming of 0.8-degree centigrade.

Atmospheric temperature over land is higher as the land heats faster than the sea, attracting moisture-laden cool winds from the sea towards landmasses and brings rainfall. Therefore, such sweltering temperature changes inadvertently affect the differential heating and cooling patterns of land and sea, disrupting the atmospheric pressure gradient and changes monsoon patterns in the country.

Environmental pollution caused by human activity is the central protagonists in such massive ramifications of global climate change. Excessive carbon dioxide emissions due to vehicular smoke and the increased burning of fossil fuels to meet ends for the ‘modern man’ in a neoliberal economy are putting the planet at the receiving end of climate change.

UNESCO (United Nations Educational Scientific and Cultural Organization), apart from deeming the Western Ghats as a ‘world heritage site’ in 2012, also bestowed the honour of being ‘one of the best examples of the monsoon systems on the planet’. The Western Ghats bordering the Deccan Plateau separates the Southern Plateau from the Arabian Sea, pulls cold air from the ocean during summer months and brings in refreshing showers in the months of June-August in the states of Karnataka, Tamil Nadu, Goa, Maharashtra, Gujarat and Kerala. But the past four decades have seen a gradually declining rainfall, especially affecting Kerala. The Indian Meteorological Department monitoring stations have recorded a 10 percent decline in annual rainfall along the western coast while also showing a significant increase in the annual and the seasonal mean temperature in all these six states.

While south-western monsoons have experienced a decline, north-eastern monsoon or what is popularly known as ‘retreating monsoon’ is hitting with full force in parts of Tamil Nadu, south-eastern Karnataka and Andhra Pradesh. The November rains which pick up moisture from the Bay of Bengal while retreating is opposing the trend of decreasing south-west monsoons which continue to affect the neighbouring regions of these states. The Chennai floods in December 2015 were majorly attributed to these retreating rains.

If we look at the rainfall data of last the three years, the south-western monsoon in June-July had arrived late, generating systematic droughts in the northern states of Rajasthan and Maharashtra. A third of the last 15 years have been drought years for India. Arguably, climate change is not the only factor that contributes to monsoonal changes with other factors such as land-use and altitudinal differences mingling with the monsoon.

Another important phenomenon that amends the Indian monsoon is El Nino Southern Oscillation (ENSO), which has global implications in determining climate.

The last massive El Nino occurred in 2015 and it was largely held responsible for the delay, intermittent pours and shortened duration of monsoon previous year. The El Nino which leads to the abnormal warming of Eastern Equatorial Pacific waters pushes the Asian monsoon to South America. Although El Nino has significantly backed the erratic monsoon in 2015, the 2014 monsoonal delay is unaccounted for.

Historically, El Nino years of 1982, 1987, 2002, 2004 and 2009 are marked as drought years in India due to the ENSO effect. However, studies have repeatedly shown that El Nino does not necessarily lead to decreased rainfall. India had experienced surplus rainfall in the 1997 El Nino, which was the strongest ever recorded. The El Nino years of 1994 and 2006 have also presented normal rainfall data in the subcontinent.

The two-week long deliberations in the climate conference COP 21 (Conference of Parties) held in Paris in 2015 marked India as one of the worst affected by Climate Change. The creation of monitoring stations across India is in the works. Although the factors distressing the monsoons are manifold, it would be difficult for scientists to deny the impact of climate change as one of the major influences in upsetting monsoon trends in India.