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Extreme weather events and agriculture: what are the impacts and what’s in store?

Farmers say they need more reliable forecasts as well as rescue, relief and rehabilitation measures – including crop insurance – to aid climate-resilient farming.

November 27, 2021 / 11:45 AM IST
Paddy in drought-stricken land. According to a report on climate change in India, regions which witnessed a significant drying trend, also experienced a higher annual frequency of droughts. Photo by International Rice Research Institute (IRRI)/Flickr.

Paddy in drought-stricken land. According to a report on climate change in India, regions which witnessed a significant drying trend, also experienced a higher annual frequency of droughts. Photo by International Rice Research Institute (IRRI)/Flickr.

Mid-October saw extreme weather events, specifically unusually heavy rains in some parts of India. In Kerala, heavy downpours — an excess of 135% for the first 19 days of the month, and most of it over a span of three days — and the landslides that followed claimed more than 30 lives. Shutters of the Idukki dam had to be opened — for just the fourth time since its construction in 1973.A day or two later, all eyes turned to Uttarakhand: heavy rainfall here exceeded the normal by a whopping 1427% between October 14 and 20 alone.

Such unusual rainfall patterns are becoming commonplace now: Hyderabad witnessed microbursts a few months ago, while large parts of western Maharashtra saw floods. How do such events impact agriculture, which is primarily rain-fed? What do these “extreme weather events” mean for farmers for the years to come, and what are the ways forward?

Extreme weather events

According to the IPCC, an extreme weather event is one that is rare at a particular place and time of year, the characteristics of which may vary from place to place.

The Indian Meteorological Department defines a heavy rainfall event as one when the daily rainfall is above 65 millimetres (mm), with extremely heavy rains at 245 mm and above, clarified climate scientist Dr. Roxy Mathew Koll of the Indian Institute of Tropical Meteorology. As per this definition based on daily rainfall, the recent rains in Kerala and Uttarakhand were both heavy-to-extreme rainfall events, he noted.

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Extreme weather events have another avatar too: droughts. According to a report on climate change in India by the Ministry of Earth Sciences (MoES) in 2020, regions which witnessed a significant drying trend (including parts of central India, the southwest coast and north-east India), also experienced a higher annual frequency of droughts (more than two droughts per decade on average, from 1951 to 2016). This has ramifications for India’s food and water security, said the report, because lower levels of soil moisture and groundwater storage can affect crop production.

India was the worst-affected due to extreme weather events in 2020, said a report recently released by Christian Aid, an international relief and humanitarian agency. Another report by the Council on Energy, Environment and Water found that between 1970 and 2005, India witnessed 250 extreme events; this however, shot up to 310 in the 14 years that followed. More than 75 percent of India’s districts, home to over 638 million people, are “extreme climate event hotspots,” found the report; and that the frequency of associated flood events such as landslides, heavy rainfall, hailstorms, thunderstorms, and cloudbursts has increased by more than 20 times between 1970 and 2019.

What’s causing these changes?

Natural variability in monsoonal systems is normal, and this has caused some big extreme weather events, said Dr. Jagdish Krishnaswamy, Dean, School of Environment and Sustainability at the Indian Institute for Human Settlements. “But overall, monsoon totals have been declining since the 1950s,” he said.

Earlier, land was heating up; now, the sea is too. The contrast between the hot land and cooler sea (which drove the monsoon patterns we used to see) is lower now: the ‘thermal gradient’ has reduced, said Krishnaswamy.

That is what a study by Koll and his team in 2014 showed: the western tropical Indian Ocean has been warming for more than 100 years now. And it continues to do so — a feature that has the potential to alter the Asian monsoon circulation and rainfall. Another analysis in 2015 by his team using historical observations and climate modelling revealed that this warming of the Indian Ocean plays a role in the weakening of the monsoon and rainfall across central India. And yet despite this, there has been a staggering three-fold increase in widespread extreme rain events across the central Indian subcontinent between 1950 and 2015, showed Koll’s 2017 study.

When natural variability is nested within such an overall warming trend, then the amplitude of these fluctuations gets amplified, commented Krishnaswamy. “That is a double whammy.”

Challenges on ground: erosion and more

When weather patterns deviate from the norm this way, farmers, whose livelihoods are tied to predictable weather patterns, are among the many who bear the brunt. News houses reported on how floods alone cost India crops standing on 18.176 million hectares of land between 2017 and 2019, according to data shared by the government in the Lok Sabha in February this year.

Wayanad in northern Kerala, for instance, is witnessing weather patterns that even old and experienced farmers have never seen before, said Rajesh Krishnan, a paddy farmer who heads the Tirunelli Agri Producer Company, a collective of around 100 organic farmers in the area.

“Both 2015 and 2016 were drought years, with a monsoon deficiency of around 65%,” he said. “Then 2018 and 2019 saw intense rains that occurred over just a couple of months, while drought-like conditions prevailed for the rest of the year.”

While landslides and land erosion that destroy standing crops are the major fallouts of such intense rain over short periods of time, erratic rains also cause another issue: pestilence. Last year, for instance, saw no visible destruction such as landslides but incessant rains that dragged into September and October caused crop yields to dip by half due to persistent bacterial and fungal crop infections, said Krishnan.

The new normal?

Unfortunately, extreme weather events are here to stay.

Changes in monsoon rains are only going to intensify further in the coming decades, wrote Koll in an email. “Particularly, the frequency, intensity and the area covered by heavy rains will increase further in the future. At the same time, we might also have long dry periods.”

Such long dry periods intermittent with short spells of heavy-to-extreme rains means that both droughts and floods will intensify, he added. What does this mean for farmers and their livelihoods?

According to Koll, this can create problems for rain-fed agriculture because we won’t get the right amount of rain at the right time. “Even if a lot of rain falls in a short time, that floods the crops and could damage it,” he said. “Also, the water will flow away quickly or evaporate instead of a gradual absorption by the terrain. This means that when the dry period comes, it can hit the crops adversely due to dryness.”

The latest report of the Intergovernmental Panel on Climate Change (IPCC) AR6 predicts that south Asia, including India, will see more extreme weather events in the years to come. The Indian subcontinent could witness more heat extremes and droughts, as well as extreme rainfall events, it says. So we need to think about how agriculture, fisheries and many other sectors which require specific moisture at specific times can adapt to this new regime, commented Krishnaswamy. What type of cropping patterns or farming practices need to be used and whether there are seasonal shifts occurring — knowledge must be synthesized, and extension services offered to farmers to adapt, he said. “That adaptive capacity currently requires a lot more investment.”

Does that make the COP26 at Glasgow in Scotland an important turning point, given that the negotiations at the Conference could facilitate on-ground actions that promote climate resilience for agriculture too?

There is definitely more evidence now that we, people in the Global South, are paying the price for decades of emissions from the north, responded Krishnaswamy. Given that we are seeing a lot of extreme events, resources for both adaptive capacity and new technology must come to developing countries, he added.

While India has done fairly well on its Nationally Determined Contributions (pledges on emission cuts made by countries under the Paris Agreement and updated every five years), the carbon that we are sequestering has to be resilient to climate shocks such as the extreme weather events we’re seeing now, he commented.

“We need to invest carbon across different ecosystems – wetlands, grasslands, forests, agroecosystems and even urban areas which require a lot of green spaces now to cope with heat stress.”

Rescue, relied and rehab

While all eyes are now turned to the COP to see how India updates its pledges and what help it obtains from the developed world, farmers have more pressing worries.

“We need more rescue, relief and rehabilitation measures,” said Krishnan.

Local agricultural departments need to respond faster to concerns such as pestilence, and relief measures such as crop insurance, though mandatory to obtain government subsidies, often never reach a farmer who has lost his crop. We need to rehabilitate our entire agricultural system with the reality of erratic weather in mind, he added.

Watershed management, for instance, can prevent loss of soil nutrients during intense rains and droughts, while land use planning and promoting farming practices that maintain biodiversity richness (such as preventing intense land tilling) can go a long way too. Resilient cropping patterns, such as having cover crops all year round, can ensure that topsoil doesn’t run off with intense rains he said.

But from a farmer’s point of view, the inability to predict local weather is the biggest failure, he said. Every farm activity, including applying manure, needs a forecast.

“It may be trivial for the rest of the world, but these are very important things for farmers because we are investing money there, and our hopes.”

There is indeed a potential for predicting organized, largescale rainfall events associated with the monsoon, since they have a strong link to ocean conditions a few weeks prior to the event, commented Koll. However, small scale events do not have that predictability and it is challenging to forecast them in advance with the current systems, he said.

The Uttarakhand rains were forecasted well in advance, though the Kerala rains were not; this is because the tropics have fast-moving small-scale weather systems and clouds which are hard to simulate with current weather models, said Koll.

“The positive note is that we are conducting cloud experiments and improving our forecast models for better predictions. We also need high density observations to characterize these localised rainfall events,” he said.
Mongabay .
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