New Delhi: Major droughts and pluvials – periods of excessive precipitation and water storage on land – have indeed been occurring more often, confirmed a new National Aeronautics and Space Administration(NASA)-led study. Droughts and floods will become more frequent and severe as our planet warms and climate changes, scientists have predicted, but detecting this on regional and continental scales has proven difficult, the study said. Two NASA, US, scientists examined 20 years of data from the NASA/German GRACE and GRACE-FO satellites to identify extreme wet and dry events, the study published in the journal Nature Water said.
Also Read: Climate Change: Lessons From Latest Global Warming
Floods and droughts account for more than 20 per cent of the economic losses caused by extreme weather events in the US each year. The economic impacts are similar around the world, though the human toll tends to be most devastating in poor neighbourhoods and developing nations.
The scientists also found that the worldwide intensity of these extreme wet and dry events – a metric that combines extent, duration, and severity – is closely linked to global warming.
From 2015-2021 – seven of the nine warmest years in the modern record – the frequency of extreme wet and dry events was four per year, compared with three per year in the previous 13 years.
This makes sense, said the authors, because warmer air causes more moisture to evaporate from Earth’s surface during dry events; warm air can also hold more moisture to fuel severe snowfall and rainfall events.
“The idea of climate change can be abstract. A couple of degrees warmer doesn’t sound like much, but water cycle impacts are tangible,” said Matt Rodell, study co-author at NASA.
Global warming is going to cause more intense droughts and wet periods, which affects people, the economy, and agriculture around the world. Monitoring hydrological extremes is important for preparing for future events, mitigating their impacts, and adapting, said Mr Rodell.
Also Read: Blog: Mitigating The Risks Of Climate Change On The Health Of Marginalised Communities
Mr Rodell and study co-author Bailing Li studied 1,056 extreme wet and dry events from 2002 to 2021, as observed by the Gravity Recovery and Climate Experiment (GRACE) and GRACE-Follow-On (GRACE-FO) satellites.
The satellites use precise measurements of Earth’s gravity field to detect water storage anomalies – specifically, how the amount of water stored in soils, aquifers, lakes, rivers, snow cover, and ice compares to normal, the study said.
“It’s like watching the level of the water in your bathtub.
You can see how much it rises and falls without knowing the total amount of water in the tub, said Mr Rodell.
Because GRACE and GRACE-FO provide a new map of water storage anomalies around the world every month, they provide a comprehensive view of the severity of hydrological events and how they evolve over time, the study said.
In their study, Mr Rodell and Bailing Li applied an “intensity” metric that accounts for the severity, duration, and spatial extent of droughts and extreme wet events.
They found the global total intensity of extreme events increased from 2002 to 2021, mirroring Earth’s rising temperatures over the same period.
According to the study, by far the most intense event identified in the study was a pluvial that began in 2019 in central Africa and is still ongoing.
It has caused the level of Lake Victoria to rise by more than one metre.
Also Read: 14 Indian States On List Of World’s Top 100 Facing Huge Climate Risk: Report
A 2015-2016 drought in Brazil was the most intense dry event of the past two decades, leading to empty reservoirs, and water rationing across some Brazilian cities, the study said.
Both events were associated with climate variability, but the Brazilian drought occurred in the warmest year on record (2016), reflecting the impact of global warming, said Bailing Li.
“The recent southwestern US and southern Europe droughts were also some of the most intense events, in part, due to anthropogenic warming,” said Bailing Li.
Global warming has had broad and profound impacts on terrestrial water storage, such as reduction of annual snow in high elevations and depletion of groundwater by people when surface waters are scarce, Bailing Li added.
“Reflecting these changes, GRACE data provide us a unique perspective of how hydrological extremes have been changing around the world,” said Bailing Li.
Also Read: Sea Level Rose By 4.5 mm Per Year During 2013-22 Period: World Meteorological Organization
(This story has not been edited by NDTV staff and is published from a syndicated feed.)
NDTV – Dettol have been working towards a clean and healthy India since 2014 via the Banega Swachh India initiative, which is helmed by Campaign Ambassador Amitabh Bachchan. The campaign aims to highlight the inter-dependency of humans and the environment, and of humans on one another with the focus on One Health, One Planet, One Future – Leaving No One Behind. It stresses on the need to take care of, and consider, everyone’s health in India – especially vulnerable communities – the LGBTQ population, indigenous people, India’s different tribes, ethnic and linguistic minorities, people with disabilities, migrants, geographically remote populations, gender and sexual minorities. In wake of the current COVID-19 pandemic, the need for WASH (Water, Sanitation and Hygiene) is reaffirmed as handwashing is one of the ways to prevent Coronavirus infection and other diseases. The campaign will continue to raise awareness on the same along with focussing on the importance of nutrition and healthcare for women and children, fight malnutrition, mental wellbeing, self care, science and health, adolescent health & gender awareness. Along with the health of people, the campaign has realised the need to also take care of the health of the eco-system. Our environment is fragile due to human activity, which is not only over-exploiting available resources, but also generating immense pollution as a result of using and extracting those resources. The imbalance has also led to immense biodiversity loss that has caused one of the biggest threats to human survival – climate change. It has now been described as a “code red for humanity.” The campaign will continue to cover issues like air pollution, waste management, plastic ban, manual scavenging and sanitation workers and menstrual hygiene. Banega Swasth India will also be taking forward the dream of Swasth Bharat, the campaign feels that only a Swachh or clean India where toilets are used and open defecation free (ODF) status achieved as part of the Swachh Bharat Abhiyan launched by Prime Minister Narendra Modi in 2014, can eradicate diseases like diahorrea and the country can become a Swasth or healthy India.
