Context

Increases in the number and days of rainfall and severity of downpour, due to human-induced climate change, may deal a blow to global economic growth, as per a new study.

• These changes are likely to take a higher toll on the manufacturing and services sectors.

Background

Rainfall pattern means the distribution of rain geographically, temporally, and seasonally.

• The study (conducted by researchers from Potsdam Institute for Climate Impact Research) looked at how rainfall patterns hurt the economy.
• The group compared daily rainfall data with subnational economic output from 77 countries between 1979 and 2019.
• It made the following revelations:
  • An increase in the number of days with rainfall exceeding one millimetre led to a substantial decline in growth rates. A rise in extreme rainfall days contributed further to this loss.
  • Extreme daily rainfall is the annual total of rain on days that exceed the 99.9th percentile of the distribution of daily rainfall between 1979 and 2019.
  • Increases in both the number and severity of extreme rainfall days within a given year reduce economic productivity.
  • Increasing wet days and extreme rainfall will likely hit prosperous countries harder. This is because these countries rely more on the manufacturing and services sectors.

Analysis

Why the rainfall pattern is changing?

• Global warming: Global warming leads to a near-term collapse of the ocean's thermohaline circulation. 

Thermohaline circulation is a global ocean circulation pattern that distributes water and heat both vertically, through the water column, and horizontally across the globe.

• Due to this collapse of thermohaline circulation, warm surface waters move from the tropics to the North Atlantic and extra-warm water surfaces in the Pacific Ocean surrounding the equator.
• Thus, Western Europe, some parts of Asia, and many parts of the Americas get warmer than normal, and some parts of Europe get cooler rapidly.
  • El Niño and La Niña are examples of this.
• This latest deviant trend generates dramatic weather impacts, such as
  • rapid cooling in some parts of the world
  • greatly diminished rainfall in agricultural and urban areas
• Shift in global wind pattern: UNESCO and other studies found that changes in rainfall pattern could be attributed to the shifts in global wind pattern. These shifts are due to the changes in the ocean surface temperature.
• Human activity: Effect of human activity on the surface vegetation is also causing rainfall pattern variation.
• Deforestation: Widespread deforestation in parts of Africa and Asia is causing scarce rainfall and subsequent drought.

The set pattern of rainfall in India The normal date for monsoon onset over India is June 1 and for monsoon withdrawal is October 15. The India Meteorological Department (IMD) closes its monsoon seasonal data on September 30. The rainfall that happens after this period is post-monsoon rainfall. This means that for the last 10 years, India’s monsoon rainfall pattern has been largely skewed. Monsoon is said to withdraw from a region when the following criteria are met: Rainfall activity ceases over the area for five continuous days an anti-cyclone establishes in the lower troposphere around 1.5 kilometres above sea level moisture content reduces Similar criteria are followed for the declaration of monsoon withdrawal from the country. The wind patterns over the country change from south-westerly direction to a more westerly direction when the monsoon retreats.

How the changing pattern can impact the manufacturing sector?

• The Indian country rely more on the manufacturing and services sectors, thus, it gets impacted from increasing wet days and extreme rainfall.
• Increases in both the number and severity of extreme rainfall days within a given year reduce economic productivity.
• India’s manufacturing industry is heavily dependent on supply chains and supply chains are heavily disrupted during extreme weather events.

Energy Policy Institute at the University of Chicago (Study) A study (2021) by Energy Policy Institute at the University of Chicago has revealed that hotter years have been routinely linked with reduced economic output in developing countries. Plants produce about 2 per cent less revenue for every one-degree rise in annual temperature. This is reflected in lower Indian GDP output in hot years and possibly also lower year-on-year growth. People are less productive at work and more likely to be absent on hot days

Why manufacturing industry is itself a climate criminal?

• Manufacturing – especially of the cheap construction staples steel and cement – accounts for about a third of global greenhouse gas emissions.
• That makes manufacturing more polluting than the power or transportation sectors, which receive far more attention in policies and investments.
• And the manufacturing sector is set to grow, as the global population climbs and countries further develop.

What are the other major consequences of changed rainfall?

• Affected agricultural sector: The world's agriculture, especially third world agriculture, depends upon the seasonal rainfall pattern. India has different agro-climatic zones.

Agro-Climatic Zones India is blessed with large arable land with 15 agro-climatic zones, having almost all types of weather conditions, soil types and capable of growing a variety of crops. Western Himalayan Region: Jammu and Kashmir, Himachal Pradesh and the hill region of Uttarakhand Eastern Himalayan Region: Arunachal Pradesh, the hills of Assam, Sikkim, Meghalaya, Nagaland, Manipur, Mizoram, Tripura, and the Darjeeling district of West Bengal Lower Gangetic Plain Region: West Bengal (except the hilly areas), eastern Bihar and the Brahmaputra valley Middle Gangetic Plain Region: Parts of Uttar Pradesh and Bihar Upper Gangetic Plains Region: Central and western parts of Uttar Pradesh and the Hardwar and Udham Nagar districts of Uttarakhand Trans-Ganga Plains Region: Punjab, Haryana, Chandigarh, Delhi and the Ganganagar district of Rajasthan Eastern Plateau and Hills: Chhotanagpur Plateau, extending over Jharkhand, Orissa, Chhattisgarh and Dandakaranya Central Plateau and Hills: Bundelkhand, Baghelkhand, Bhander Plateau, Malwa Plateau, and Vindhyachal Hills Western Plateau and Hills: Southern part of Malwa plateau and Deccan plateau (Maharashtra) Southern Plateau and Hills: Interior Deccan and includes parts of southern Maharashtra, the greater parts of Karnataka, Andhra Pradesh, and Tamil Nadu uplands from Adilabad District in the north to Madurai District in the south Eastern Coastal Plains and Hills: Coromandal and northern Circar coasts of Andhra Pradesh and Orissa Western Coastal Plains and Ghats: Malabar and Konkan coastal plains and the Sahyadris Gujarat Plains and Hills: Hills and plains of Kathiawar, and the fertile valleys of Mahi and Sabarmati rivers Western Dry Region: West of Aravalli (Rajasthan) Island Region: Andaman-Nicobar and Lakshadweep

• Food insecurity: Recent erratic changes in rainfall pattern lead toward low agriculture production, thus creating food insecurity for an ever-increasing world population.
• Migration: Rainfall pattern variability would certainly cause mass human migration.
• Increased disasters: Flood, drought, and famine are the consequences of these changing patterns.

Why this study assumes significance for India?

• The study offers important lessons for India as the country aims to become a manufacturing hub.
  • The sector currently contributes roughly 17 per centto GDP.
  • Its share in employment was 7.3 per cent in 2020-2021.
• According to India Brand Equity Foundation projections, India can add more than $500 billion annuallyto the global economy.
• But the manufacturing sector is vulnerable to climate change. The sector is heavily dependent on supply chains and supply chains are heavily disrupted during extreme weather events.

Way forward

If this trend of changed rainfall pattern continued, environmental managers need to make new decisions about the management of water and land. They need to accurately understand the inter-annual variability of rainfall and a possibility of runs of dry and wet years, which may cause important changes in runoff, sedimentation, soil erosion, or changes in communities of vegetation and animals, and of the viability of large water resource developments.