Singapore:

Climate change is driving changes in rainfall patterns across the world, scientists said in a paper published on Friday, which could also be intensifying typhoons and other tropical storms.

Taiwan, the Philippines and then China were lashed by the year’s most powerful typhoon this week, with schools, businesses and financial markets shut as wind speeds surged up to 227 kph (141 mph). On China’s eastern coast, hundreds of thousands of people were evacuated ahead of landfall on Thursday.

Stronger tropical storms are part of a wider phenomenon of weather extremes driven by higher temperatures, scientists say.

Researchers led by Zhang Wenxia at the China Academy of Sciences studied historical meteorological data and found about 75% of the world’s land area had seen a rise in “precipitation variability” or wider swings between wet and dry weather.

Warming temperatures have enhanced the ability of the atmosphere to hold moisture, which is causing wider fluctuations in rainfall, the researchers said in a paper published by the Science journal.

“(Variability) has increased in most places, including Australia, which means rainier rain periods and drier dry periods,” said Steven Sherwood, a scientist at the Climate Change Research Centre at the University of New South Wales, who was not involved in the study.

“This is going to increase as global warming continues, enhancing the chances of droughts and/or floods.”

FEWER, BUT MORE INTENSE, STORMS

Scientists believe that climate change is also reshaping the behaviour of tropical storms, including typhoons, making them less frequent but more powerful.

“I believe higher water vapour in the atmosphere is the ultimate cause of all of these tendencies toward more extreme hydrologic phenomena,” Sherwood told Reuters.

Typhoon Gaemi, which first made landfall in Taiwan on Wednesday, was the strongest to hit the island in eight years.

While it is difficult to attribute individual weather events to climate change, models predict that global warming makes typhoons stronger, said Sachie Kanada, a researcher at Japan’s Nagoya University.

“In general, warmer sea surface temperature is a favourable condition for tropical cyclone development,” she said.

In its “blue paper” on climate change published this month, China said the number of typhoons in the Northwest Pacific and South China Sea had declined significantly since the 1990s, but they were getting stronger.

Taiwan also said in its climate change report published in May that climate change was likely to reduce the overall number of typhoons in the region while making each one more intense.

The decrease in the number of typhoons is due to the uneven pattern of ocean warming, with temperatures rising faster in the western Pacific than the east, said Feng Xiangbo, a tropical cyclone research scientist at the University of Reading.

Water vapour capacity in the lower atmosphere is expected to rise by 7% for each 1 degree Celsius increase in temperatures, with tropical cyclone rainfall in the United States surging by as much as 40% for each single degree rise, he said.

(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)

Watch | Earth Day: wake-up call on climate change

In this episode, we will be discussing Earth Day, which The Hindu covered with thematic articles on April 22.

We look at multiple dimensions of climate change, beginning with the most recent Supreme Court ruling on climate change in terms of the rights of us citizens of India to have protection from the deleterious impact of climate change.

We look at heatwave projections for the entire Asia region in terms of what impact it could have on livelihoods, employment etc. We will also look at how algorithms can be used to project future droughts and floods across the region. And finally, we touch on the critical issue of water management and why it matters in the context of water-food-land nexus which together has an enormous impact on the economy.

We are joined by Jacob Koshy, the Deputy Science Editor at The Hindu.

Host: Narayan Lakshman

Guest: Jacob Koshy

Production: Richard Kujur

Homes are surrounded by floodwaters in Sohbat Pur city, a district of Pakistan’s southwestern Baluchistan province
| Photo Credit: Zahid Hussain

Disaster events are not only becoming more frequent and severe but their impact is also expected to worsen. The year 2023 brought an end to the warmest decade on record, marked by unprecedented extreme weather events and large-scale disasters. These catastrophes were worsened by ongoing conflicts and the COVID-19 pandemic.

A report by the Food and Agriculture Organization titled ‘The Impact of Disaster on Agriculture and Food Security’ found that the frequency of extreme disaster events has risen significantly over the past 50 years. The 1970s saw approximately 100 disaster events per year. In the last 20 years, that number went up to about 400, globally (Chart 1). 

Chart 1 | The chart shows the number of disasters by EM-DAT (the international disaster database) grouping and total economic losses in $ billion.

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According to the EM-DAT database of the Centre for Research on the Epidemiology of Disasters, 2022 witnessed nearly 31,000 deaths and an estimated $223.8 billion in economic losses from disasters, affecting over 185 million people. 

Agricultural activities and livelihoods rely heavily on environmental conditions, natural resources, and ecosystems. Globally, the agriculture sector faces growing threats from hazards such as flooding, water scarcity, drought, diminishing agricultural yields, fisheries depletion, loss of biodiversity, and environmental degradation. For instance, in Pakistan, exceptional monsoon rainfalls in 2022 led to nearly $4 billion in damages to the agricultural sector. In the U.S., the National Oceanic and Atmospheric Administration estimated over $21.4 billion in crop and rangeland losses in 2022, with drought and wildfires responsible for most of the crop losses.

Data from 88 Post-Disaster Needs Assessment surveys conducted from 2007 to 2022 in 60 countries indicated that agricultural losses constituted an average of 23% of the overall impact of disasters across all sectors. However, the available data are limited, primarily focusing on low-income countries and major extreme events. A comprehensive global estimate of economic losses across all sectors is unavailable.

PDNAs revealed that more than 65% of losses attributed to drought affected the agricultural sector, while floods, storms, cyclones, and volcanic activities each accounted for roughly 20% (Chart 2). 

Chart 2 | The chart shows the share of loss in agriculture by hazard type. 

However, data on loss and damage are not systematically collected or reported. To address this gap, the report used secondary data sources such as EM-DAT and FAOSTAT production data to quantify the impact of disasters on agriculture, with a specific focus on crop and livestock production. Findings indicated that estimated losses in these sub-sectors have been gradually increasing over the past three decades. 

The total loss from extreme events over the past 31 years amounted to approximately $3.8 trillion, averaging about $123 billion per year. 

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Losses across major crop and livestock product groups exhibited increasing trends (Chart 3). Over the past three decades, estimated losses in cereals averaged 69 million tonnes annually. Losses in fruits and vegetables, along with sugar crops, averaged 40 million tonnes each annually. Meats, dairy products, and eggs experienced an estimated loss of 16 million tonnes per year. 

Chart 3 | The chart shows the estimated loss in various product groups (in million tonnes) between 1991 and 2021.

The distribution of total losses across regions from 1991 to 2021 also reflected the geographic size of each region. Asia bore the largest share of economic losses (45%), while Africa, Europe, and the Americas displayed similar orders of magnitude. Oceania experienced the lowest total losses (Chart 4).

Chart 4 | The chart shows the distribution of the total estimated $3.8 trillion losses by region (1991-2021).

In absolute terms, high-income countries, lower-middle-income countries, and upper-middle-income countries reported higher losses, while low-income countries and Small Island Developing States experienced lower levels. However, when considering losses relative to agricultural value added, low-income countries suffered losses more than double those of upper-middle-income countries on average (Chart 5).

Chart 5 | The chart shows total agricultural losses as a share of agricultural GDP by country groups (1991-2021).

Source: FAO report titled “The Impact of Disasters on Agriculture and Food Security 2023”

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Guwahati:

The flood situation in Assam turned grim on Monday with over 1.90 lakh people affected by the deluge and one person dying, according to an official bulletin.

Incessant rains in the higher altitudes have led to an increase in water levels of most rivers with many flowing above the danger mark in different parts of the state, it said.

Ferry services on the Brahmaputra river have been suspended in Guwahati, and at Nematighat in Jorhat due to the rising water levels.

The Assam State Disaster Management Authority (ASDMA) said one death was reported from Demow in Sivasagar district, taking the toll to 15 in this year’s flood.

As many as 17 districts are currently reeling under the deluge, affecting 1,90,675 people, it said.

The worst hit is Lakhimpur district where 47,338 people have been affected, followed by Dhemaji with 40,997 affected population.

Altogether 427 people are taking refuge in two relief camps, while 45 relief distribution centres are functional.

Local administration and SDRF are carrying out rescue operations in different affected areas, the ASDMA said.

Among the major rivers flowing above the danger level is the Brahmaputra in Dibrugarh, Dhubri, Tezpur and Nematighat in Jorhat.

The Beki, Jia-Bharali, Disang, Dikhou and Subansiri rivers have also breached the red mark, the ASDMA bulletin said.

The Inland Water Transport Department said that ferry services in Guwahati will remain suspended from Tuesday in view of the rising water level of the Brahmaputra.

It also said that following incessant rain in higher altitudes leading to a surge in water levels of downstream rivers, ferry services between Nematighat and Majuli have been suspended.

The ASDMA said 8,086.40 hectares of cropland is currently under the floodwaters, and 1,30,514 animals have been affected, including 81,340 large animals and 11,886 poultry.

Breach of embankments by floodwaters were reported from two areas in Udalguri, and one each in Biswanath and Darrang, it said.

Roads, bridges, power poles and schools, among others, were also damaged in the flood, it added.

Erosions were reported from Barpeta, Biswanath, Dhubri, Lakhimpur, Morigaon, Nalbari, Sivasagar, Sonitpur, Tinsukia and Udalguri, the ASDMA bulletin said.

(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)