Monsoon to get longer in India [sub-continent]: IPCC

NEW DELHI: North India is likely to heat up more than the southern parts of the country while the entire Indian subcontinent may see longer rainy seasons in second half of the century, the UN's climate body has predicted in its latest comprehensive document on climate change.

The conclusion, showing variation in temperature and rainfall in South Asia, is part of the lengthy technical details of the United Nation's Intergovernmental Panel on Climate Change (IPCC) which made its comprehensive report — Climate Change 2013, The Physical Science Basis — public in Stockholm on Monday.

The findings of the report show that the northern part of the continent is likely to witness winter temperatures rise of up to 0.4 to 0.8 degree Celsius during 2016-35 as compared to the 1986-2005 average, 2 to 3 degree Celsius during 2046-65 and up to 3 to 5 degree Celsius by the end of the century (2081-2100), under different scenarios of action to limit greenhouse gas emissions.

Though the UN body's report on region-wise "impact, adaptation and vulnerability" will come out in March next year, the technical details comprising 14 chapters and Atlas of Global and Regional Climate Projections in its annexure carry indications of these changes in South Asia.

Krishna Kumar Kanikicharla, climate scientist at Pune's Indian Institute of Tropical Meteorology and one of the drafting authors of the IPCC report, told TOI there was "growing evidence" of the impact of the climate change on monsoons in South Asia and the tropical cyclone system in the Bay of Bengal.

Kanikicharla, responsible for drafting the chapter comprising details of monsoon systems, said: "There is strong hint that the duration of the rainy season would increase due to early onset of monsoon. The quantum of rainfall will also increase during the later part of this century."

He said though the Indian summer monsoon circulation will weaken, rainfall will increase due to higher atmospheric moisture resulting from a rise in temperatures.

In its projection for South Asia, the technical summary of the report clearly points at "enhanced summer monsoon precipitation and increased rainfall extremes of landfall cyclones on the coasts of the Bay of Bengal and Arabian Sea".

What is the confidence level of these predictions? Prashant Goswami, one of the lead authors of the IPCC report, admitted that these conclusions were based on climatic projections that were not as firm as those made at a global level.

"These uncertainties increase as you go to smaller scale (from global to regional or from regional to sub-regional levels). But one has to have an element of faith in these conclusions which are based on well defined scientific methodology," Goswami, chief scientist at Bangalore's CSIR Centre for Mathematical Modelling and Computer Simulation, told TOI.

The impact of temperature rise and rainfall variations on the region's agriculture that's highly dependent on monsoon, will be considered in the report on impact, adaptation and vulnerability, to be released next year as part of the IPCC's fifth assessment report (AR5). More

 

North African Countries Commit to Cooperative Management of Nubian Aquifer read more: http://land-l.iisd.org/news/north-african-countries-commit-to-cooperative-management-of-nubian-aquifer/

18 September 2013: Chad, Egypt, Libya and Sudan signed a Strategic Action Programme to establish a long-term framework for managing the Nubian Sandstone Aquifer System (NSAS), the world's largest known fossil water aquifer system.

The agreement establishes a Joint Authority for the NSAS, with the aim of strengthening regional coordination and optimizing equitable use among the four arid North African countries.

The Aquifer is the main water resource for humans, livestock, irrigation and industry in this region, and is under pressure from increasing populations, agricultural expansion and decreasing water availability from other sources. The agreement seeks to strengthen transboundary water cooperation among the four countries to ensure water removal does not threaten water quality, harm the surrounding desert ecosystem and its biodiversity, or accelerate land degradation. The agreement is based on an ecosystem-based management approach (EBMA) and integrated water resources management (IWRM), and includes transboundary actions and targets that individual countries are expected to translate into national actions.

The agreement resulted from a technical cooperation project among the International Atomic Energy Agency (IAEA), the UN Development Programme (UNDP), the Global Environment Facility (GEF) and the UN Educational, Scientific and Cultural Organization (UNESCO). The project, which began in 2006, created an aquifer model to assist the countries in optimizing the aquifer's use for human needs and ecosystem protection. The project also improved understanding of the transboundary ecosystem threats and improved data sharing. The Programme will build upon this project by continuing to strengthen the countries' capacity to monitor groundwater quantity and quality, and providing a framework for transboundary cooperation.

UNDP Administrator Helen Clark congratulated the African countries on the agreement, saying cooperative management of their shared sub-surface waters “will help to ensure maintenance of livelihoods and ecosystems dependent upon the aquifer." The agreement was signed at IAEA headquarters in Vienna, Austria. [UN Press Release] [UNDP Press Release] [GEF Press Release] [Strategic Action Programme Agreement]

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Littlest continent had biggest role in sea level drop [and rainfall]

A unique and complex set of circumstances came together over Australia from 2010 to 2011 to cause Earth's smallest continent to be the biggest contributor to the observed drop in global sea level rise during that time, finds a new study co-authored and co-funded by NASA.

In 2011, scientists at NASA's Jet Propulsion Laboratory in Pasadena, Calif., and the University of Colorado at Boulder reported that between early 2010 and summer 2011, global sea level fell sharply, by about a quarter of an inch, or half a centimeter. Using data from the NASA/German Aerospace Center's Gravity Recovery and Climate Experiment (GRACE) spacecraft, they showed that the drop was caused by the very strong La Nina that began in late 2010. That La Nina changed rainfall patterns all over our planet, moving huge amounts of Earth's water from the ocean to the continents. The phenomenon was short-lived, however.

By mid-2012, global mean sea level had resumed its long-term mean annual rise of 0.13 inches (3.2 millimeters) per year (see http://www.jpl.nasa.gov/news/news.php?release=2012-362).

But analyses of the historical record showed that past La Nina events only rarely accompanied such a pronounced drop in sea level. So what made this particular La Nina unique?

To better understand this phenomenon, scientists at the National Center for Atmospheric Research (NCAR) in Boulder, Colo.; JPL; and the University of Colorado at Boulder combined GRACE data with data from the Argo global array of 3,000 free-drifting floats and satellite altimeters (Jason-1, Jason-2 and Topex/Poseidon).

They found that three atmospheric patterns converged over the Indian and Pacific Oceans in 2010 and 2011 to drive excessive precipitation over Australia. On average, the continent received almost one foot (300 millimeters) of rain more than normal. The result was widespread flooding. The flooding was in large part prevented from running back into the ocean by Australia's dry soils and the mountain-ringed topography of the country's vast interior, called the Outback, leading to the measurable drop in the world's ocean levels.

"No other continent has this combination of atmospheric set-up and topography," said NCAR scientist John Fasullo, lead author of the study. "Only in Australia could the atmosphere carry such heavy tropical rains to such a large area, only to have those rains fail to make their way to the ocean."

Now that the atmospheric patterns have snapped back and more rain is falling over tropical oceans, the seas are rising again. In fact, with Australia in a major drought, they are rising faster than before. Since 2011, when the atmospheric patterns shifted out of their unusual combination, sea levels have been rising at a faster pace of about 0.4 inches (10 millimeters) per year.

The study, co-funded by NASA and the National Science Foundation, will be published next month in the journal Geophysical Research Letters.

For more information, read the full NCAR news release: http://www2.ucar.edu/atmosnews/news/10090/global-sea-level-rise-dampened-australia-floods.

 

Northeast Pakistan hit by 'surprise' floods, as monsoon rains intensify

SIALKOT, Pakistan (Thomson Reuters Foundation) - “We kept quivering with fear the whole night and could not sleep even a wink,” recalled Salma Zehra, a mother of five teenage children. The family trembled to think that the roof of their mud house could cave in at any time, as the rain lashed down in a huge thunderstorm.

Mehtabpur, District Sialkot, Pakistan

By early morning on July 22, the house in Mehtabpur village in northeast Pakistan’s Sialkot district was waist-deep in water. The torrential downpour had left Zehra’s two buffaloes dead, the 45-year-old said in a shaky voice.

Another bout of heavy rain followed later that night. The Dek tributary of the Chenab River in Sialkot, 192 km (122 miles) from Islamabad, burst its banks, submerging more than 72 villages in the district.

Besides Sialkot, other districts in Punjab province have also suffered massive damage to crops across 1,000 hectares of land, as well as to properties. According to the district disaster management authorities of Sialkot, Gujranwala and Narowal, an estimated 400 villages have been flooded.

Officials have declined to give final figures for the losses, but say dozens have died and thousands of people remain stranded in the affected parts of the three districts. Some are starting to return home, but many houses have collapsed and must be rebuilt, they report.

Sialkot District Coordination Officer Iftikhar Ali Sahu told Thomson Reuters Foundation thousands of people had been trapped on the roofs of their houses during the worst of the flooding. “Mortality among cattle is high - the number of dead animals continued to rise as the floodwaters began to recede on July 26,” he added.

The situation in adjoining districts is just as bad. In Narowal alone, around 2,000 people were marooned on their rooftops in some seven villages a week ago.

Less than 30 percent of the floodwater has yet to recede, according to Mujahid Sherdil, director-general of the Punjab Provincial Disaster Management Authority.

Machines have been brought in to help drain water out of the flood-affected areas, and he hopes the task will be accomplished in the next two to three days, he told Thomson Reuters Foundation from Lahore.

Sherdil said the torrential rainfall had caused breaches of irrigation canals, streams and natural dams, and the floods had washed away crops, livestock, roads, bridges, buildings and even entire villages.

Farmers say surviving cattle in flood-hit areas are now at risk.

“Besides paddy, maize and vegetable crops, fodder fields are also underwater. This has created an acute shortage of fodder, and it is barely possible to save our cattle from the looming threat of hunger and disease,” said Zehra’s husband, Ghulam Abbas.

METEOROLOGISTS ‘STARTLED’

The above-normal monsoon rains in Punjab’s northeastern districts have taken weather experts by surprise.

“Last month, we predicted that this year monsoon rains across the country would remain normal with no possibility of flooding. But unexpected heavy rains in the northeastern districts are startling for us,” said Ghulam Rasul, a senior weather scientist at the Pakistan Meteorological Department (PMD) in Islamabad. “This shows how monsoon rains have become erratic and unpredictable in timing, volume and intensity.”

Sherdil, head of the Punjab disaster management agency, said the heavy rains and flooding had caught them unprepared.

“We were closely following the weekly and monthly forecasts of PMD that never predicted heavy rains of unprecedented significance for July in northeastern parts, which have been nearly 40 percent above normal for the month,” he said.

It has been difficult to get aid into the affected areas due to damaged and flooded roads and bridges, he said. “Nevertheless, we left no stone unturned to get the emergency relief items including food, medicines, to the flood victims on boats – although (they arrived) a bit late,” he added.

MONSOON SHIFTS

In June 2012, scientists argued in the Nature Climate Change journal that global warming would make understanding changes in the South Asian monsoon more difficult.

They said the impacts of short- and long-term monsoon shifts would affect the lives of over a billion people in the region, who rely on rainfall for agriculture, hydropower generation, economic growth and basic human needs.

Understanding how the South Asian monsoon will alter due to climate change is necessary to cope with the effects, reduce the risk of disasters and safeguard people’s livelihoods, they underlined.

“Addressing the uncertainties in projected changes of the monsoon variability in coming years will remain a daunting challenge for climate scientists,” said Arshad Abbasi, a water and energy expert at the Sustainable Development Policy Institute in Islamabad.

Arshad Khan, the executive director of the Global Change Impact Study Centre (GCISC), the research arm of Pakistan’s Federal Climate Change Division, said the country is in the grip of unpredictable weather patterns.

Intense monsoon rains will be a common phenomenon, particularly on the country’s southern plains which lack water reservoirs and are highly vulnerable to floods, he warned.

And a spurt in the speed of glacial melt, due to rising global temperatures and above-normal monsoon rains, is likely to cause rivers to overflow and burst their banks across the country, he added.

GOVERNMENT EFFORTS

Officials at the Climate Change Division, which operates under the oversight of the prime minister, said efforts are underway to tackle the vagaries of climate change across different sectors of the economy, particularly agriculture and water.

“Consultations are being made with national and provincial disaster management authorities, and officials of federal and provincial environment, agriculture, irrigation departments to implement national climate change policy to mitigate the impacts of changing weather patterns and erratic monsoon rains,” said a senior official, who coordinates policy at federal and provincial levels.

The Climate Change Division is developing climate adaptation plans for the agriculture, water and irrigation sectors, which will be implemented in Pakistan’s four provinces in collaboration with international NGOs and provincial government offices.

It is also working on programmes to ensure that climate change is considered in other sectors such as health and education, to make them more climate-resilient.

Abbasi of the Sustainable Development Policy Institute said the best ways to avert the growing threat of floods in Pakistan include efficient watershed management, reforestation in northern mountain areas and the revival of riverine forests.

Saleem Shaikh and Sughra Tunio are Islamabad-based journalists specialising in climate change and development issues. More

Rivers' in air could boost flooding

Winter floods could intensify in Britain, [and countries globally] according to new research into powerful weather systems called "atmospheric rivers".

Only identified about 20 years ago, atmospheric rivers are intense bands of moisture that flow through the air.

Known to be responsible for heavy rainfall, they have been blamed for severe flooding in California and the UK.

The new study suggests that warmer conditions could create more rivers - and make them more severe.

The paper is published by the Institute of Physics in Environmental Research Letters.

Atmospheric rivers are up to 300km wide and can stretch in length for over 1,000-2,000km. They flow invisibly between 1-2.5km above the surface of the ocean.

One atmospheric river is believed to have been behind the violent flooding that hit Cockermouth in Cumbria on 19 November 2009.

The flooding claimed the life of a policeman, PC Bill Barker, who died after a bridge collapsed.

The researchers, led by Dr David Lavers of the University of Iowa, have estimated the staggering volume of moisture carried by this particular atmospheric river.

They calculate that at its peak it was transporting almost 300,000 tonnes of moisture every second.

By comparison, the River Thames carries about 65 tonnes of water through London over the same period.

Remain on course

If the rivers make landfall and encounter a steep rise in terrain, the air is forced upwards where it cools and releases the moisture in the form of rain.

On top of that, if the river remains on the same course for 24 hours - as it did over Cumbria in 2009 - it will deliver a continuous flow of heavy rain over the same area.

The most closely-studied atmospheric river, which flows towards the California coast, has been dubbed the "Pineapple Express" because it usually originates from the region of Hawaii.

It has been linked to a number of extremely damaging storms along the US West Coast.

Over the last 30 years, there has been an average of 9-11 of the strongest atmospheric river events hitting Britain every year.

In this latest study, the researchers examined five different modelling scenarios to simulate possible conditions this century and found that a warming climate - which allows the atmosphere to hold more moisture - made the rivers more likely.

Dr Lavers said: "All five models suggest that there could be a doubling of atmospheric river events in the period 2074-99 and most of those could be expected to make landfall in the UK.

"One of the big things is that these are the most relevant feature of winter flooding in Britain and the work is certainly suggesting an increase in strength and frequency."

Computer modelling

Among the uncertainties about the research are the reliability of the models used to generate the future scenarios and possible shifts in the patterns of the winds - a change of course away from the UK would reduce the risk.

It was research in the 1970s that first identified "conveyor belts" of moisture travelling through the atmosphere, with later studies in the early 1990s detecting much narrower bands of intense vapour that became known as atmospheric rivers.

Dr Richard Allan of Reading University, also an author of the paper, said: "What this shows is that the dominating factor is the increase in water vapour which means that if you've got more moisture - and the winds don't change -then you've got a much bigger potential for flooding.

"These are really massive flows of invisible water which can feed clouds and cause rainfall if forced up over mountains."

The researchers say the study could help guide forecasters trying to give warning of future flood risks. More

 

Climate Change and the South Asian Summer Monsoon

ScienceDaily (June 24, 2012) — The vagaries of South Asian summer monsoon rainfall impact the lives of more than one billion people. A review in Nature Climate Change (June 24 online issue) of over 100 recent research articles concludes that with continuing rise in CO₂ and global warming, the region can expect generally more rainfall, due to the expected increase in atmospheric moisture, as well as more variability in rainfall.

In spite of the rise in atmospheric CO₂ concentration of about 70 parts per million by volume and in global temperatures of about 0.50°C over the last 6 decades, the All India Rainfall index does not yet show the expected increase in rainfall. The reviewers Andrew Turner from the Department of Meteorology at the University of Reading and H. Annamalai from the International Pacific Research Center at the University of Hawaii at Manoa give several reasons for why the region's observed rainfall has not yet increased, among them are inconsistent rainfall observations, decadal variability of the monsoon, the effects of aerosols resulting from industrialization, and land-use changes.

Regional projections for devastating droughts and floods--which are most meaningful for residents living in South Asia-- are still beyond the reach of current climate models, according to the reviewers' detailed analyses of the present state of research. The authors conclude that in order to make regional projections that can help in disaster mitigation and in adapting to climate change, the following is needed: establishing more consistent rainfall datasets by expanding observations to include, for example, agricultural yield; a better grasp of the complicated thermodynamics over the monsoon region and of the interactions among monsoon rainfall, land-use, aerosols, CO₂, and other conditions; and an evaluation in coupled circulation models (which allow feedbacks among variables) of those processes that have been shown in simpler models to affect the monsoon and rainfall. More

 

Past in Monsoon Changes Linked to Major Shifts in Indian Civilizations

ScienceDaily (Mar. 16, 2012) — A fundamental shift in the Indian monsoon has occurred over the last few millennia, from a steady humid monsoon that favored lush vegetation to extended periods of drought, reports a new study led by researchers at the Woods Hole Oceanographic Institution (WHOI). The study has implications for our understanding of the monsoon’s response to climate change.

The Indian peninsula sustains over a billion people, yet it lies at the same latitude as the Sahara Desert. Without a monsoon, most of India would be dry and uninhabitable. The ability to predict the timing and amount of the next year’s monsoon is vital, yet even our knowledge of the monsoon’s past variability remains incomplete.

One key to this understanding lies in the core monsoon zone (CMZ) – a region in the central part of India that is a very sensitive indicator of the monsoon throughout the India peninsula.

“If you know what’s happening there, you know more or less what’s happening in the rest of India,” said Camilo Ponton, a student in the MIT-WHOI Joint Program in Oceanography and lead author of the study recently published in Geophysical Research Letters entitled "Holocene Aridification of India". “Our biggest problem has been a lack of evidence from this region to extend the short, existing records.”

The study was designed by WHOI geologist Liviu Giosan and geochemist Tim Eglinton, now at ETH in Zurich, and makes use of a sediment core collected by the National Gas Hydrate Program of India in 2006. Sailing around India aboard the drilling vessel JOIDES Resolution for several months, Giosan enlisted colleagues from India and US to help with the project. Extracted from a “sweet spot” in the Bay of Bengal where the Godavari River drains the central Indian peninsula and over which monsoon winds carry most of the precipitation, the core has provided the basis for a 10,000-year reconstruction of climate in the Indian peninsula’s CMZ .

“We are fortunate to have this core from close to the river mouth, where it accumulates sediment very fast,” said Ponton. “Every centimeter of sediment contains 10 to 20 years’ worth of information. So it gives us the advantage of high temporal resolution to address the problems.”

When put together, the research tells the story of growing aridity in India, enables valuable insights into the impact of the monsoon on past cultures, and points scientists toward a way to model future monsoons.

To assemble the 10,000-year record, the team looked to both what the land and the ocean could tell them. Contained within the sediment core’s layers are microscopic compounds from the trees, grasses, and shrubs that lived in the region and remnants of plankton fossils from the ocean.

“The geochemical analyses of the leaf waxes tell a simple story,” said Giosan. “About 10,000 years ago to about 4500 ago, the Godavari River drained mostly terrain that had humidity-loving plants. Stepwise changes starting at around 4,000 years ago and again after 1,700 years ago changed the flora toward aridity-adapted plants. That tells us that central India – the core monsoon zone – became drier.”

Analyses of the plankton fossils support the story reconstructed from plant remains and reveal a record of unprecedented spikes and troughs in the Bay of Bengal’s salinity – becoming saltier during drought periods and fresher when water from the monsoon filled the river and rained into the Bay. Similar drought periods have been documented in shorter records from tree rings and cave stalagmites within India lending further support to this interpretation.

With a picture emerging of changes in the ancient flora of India, Giosan tapped archaeobotanist Dorian Fuller’s interest.

“What the new paleo-climatic information makes clear is that the shift towards more arid conditions around 4,000 years ago corresponds to the time when agricultural populations expanded and settled village life began,” says Fuller of the Institute of Archaeology, University College London. “Arid-adapted food production is an old cultural tradition in the region, with cultivation of drought-tolerant millets and soil-restoring bean species. There may be lessons to learn here, as these drought-tolerant agricultural traditions have eroded over the past century, with shift towards more water and chemical intensive forms of modern agriculture.”

Together, the geological record and the archaeological evidence tell a story of the possible fate of India’s earliest civilizations. Cultural changes occurred across the Indian subcontinent as the climate became more arid after ~4,000 years. In the already dry Indus basin, the urban Harappan civilization failed to adapt to even harsher conditions and slowly collapsed. But aridity favored an increase in sophistication in the central and south India where tropical forest decreased in extent and people began to settle and do more agriculture. Human resourcefulness proved again crucial in the rapid proliferation of rain-collecting water tanks across the Indian peninsula, just as the long series of droughts settled in over the last 1,700 years.

What can this record tell us about future Indian monsoons? According to Ponton, “How the monsoon will behave in the future is highly controversial. Our research provides clues for modeling and that could help determine whether the monsoon will increase or decrease with global warming.”

The study found that the type of monsoon and its droughts are a function of the Northern Hemisphere’s incoming solar radiation – or “insolation.” Every year, the band of heavy rain known as the Inter-Tropical Convergence Zone, or ITCZ, moves north over India.

“We found that when the Asian continent is least heated by the sun, the northward movement of the rain appears to hesitate between the Equator and Asia, bringing less rain to the north,” said Giosan. “The fact that long droughts have not occurred over the last 100 years or so, as humans started to heat up the planet, but did occur earlier, suggest that we changed the entire monsoon game, and may have inadvertently made it more stable!” More