Karachi thirsts for a water supply

KARACHI: On the outskirts of the slums of Pakistan’s biggest city, protesters burning tires and throwing stones have what sounds like a simple demand: They want water at least once a week.

In Karachi people go days without getting water from city trucks, sometimes forcing them to use groundwater contaminated with salt. A recent drought has only made the problem worse. And as the city of roughly 18 million people rapidly grows, the water shortages are only expected to get worse.

“During the last three months they haven’t supplied a single drop of water in my neighbourhood,” protester Yasmeen Islam said. “It doesn’t make us happy to come on the roads to protest but we have no choice anymore.”

Karachi gets most of its water from the Indus River — about 550 million gallons per day — and another 100 million gallons from the Hub Dam that is supplied by water from neighbouring Balochistan province. But in recent years, drought has hurt the city’s supply.

Misbah Fareed, a senior official with the Karachi Water and Sewerage Board that runs the city’s water supplies, said that only meets about half the city’s needs — 1.2 billion gallons a day.

Karachi’s water distribution network has exacerbated the problem by forcing much of the city to get its water through tankers instead of directly from pipes. The Karachi Water and Sewerage Board operates 12 water hydrants around the city where tankers fill up and then distribute. Even people in the richest areas of the city get their water through tankers that come a few times a week to fill up underground cisterns.

But criminals have illegally tapped into the city’s water pipes and set up their own distribution points where they siphon off water and sell it.

“I personally know some people previously associated with drug mafias who now switched to the water tanker business,” Fareed said. “Just imagine how lucrative the business is.”

Other areas of Pakistan pump massive amounts of groundwater. But in the coastal city of Karachi, the underground water is too salty to drink. Many people have pumps but they use the water for things such as showering or washing clothes.

The water shortage is exacerbated by Karachi’s massive population. Pakistani military operations and American drone strikes in the northern tribal regions, as well as natural disasters such as flooding and earthquakes, have pushed people toward a city long seen as the economic heart of Pakistan.

The city is trying to increase the amount of water it gets from the Indus River by building another canal — dubbed the K4 project. But even if they were to get political approval from the capital to take more water from the river, it would take a minimum of four years to build.

But analysts say supply isn’t the only problem. Farhan Anwar, who runs an organisation called Sustainable Initiatives in Karachi, said the Karachi Water and Sewerage Board is horribly overstaffed and many of those are political appointees. The cost for water is also very low and the agency doesn’t collect all that it’s due, Anwar said. That’s made it difficult to upgrade the ageing pipes the system does have, meaning contamination and leakages are common.

Meanwhile, Karachi residents have to spend more money or walk further and further to get water. One elderly resident Aisha Saleem said in recent months even the little water they get from the water board is salty.

“Women and kids have to go miles by foot and carry drinking water every day,” she said More

 

© 2014

Study: Climate change linked to extreme rain

John Fogerty once crooned "Who'll stop the rain?" Not humanity, apparently, as new research shows that human-caused climate change has significantly increased the chances of extreme rain- and snowfall around the world, along with the deadly floods that follow.

Pakistan floods 2011

This is according to two new studies published Wednesday in the British journal Nature.

While other studies have suggested that global warming may be partly responsible for an increase in heavy precipitation, what's new in this study is the formal finding that human influence has "likely made intense precipitation stronger, on average, over the second half of the 20th century," says study co-author Francis Zwiers of the University of Victoria in British Columbia.

"The observed change cannot be explained by natural fluctuations of the climate system alone," he says.

One of the studies reported that that the most significant rain and snow events were 7 percent wetter in the 1990s than they had been in the 1950s.

Scientists based their findings on rainfall data from 1951 to 1999 in Northern Hemisphere land areas, including North America, Eurasia and India.

The scientists took all the information that showed an increase in extreme rain and snow events from the 1950s through the 1990s, and ran dozens of computer models numerous times. They put in the effects of greenhouse gases -- which come from the burning of fossil fuels -- and then ran numerous models without those factors.

Only when the greenhouse gases are factored in did the models show a similar increase to what actually happened. Essentially, the computer runs show climate change is the only way to explain what's happening.

The other study dealt with the floods that swamped the U.K. in fall 2000 and determined that climate change made them over twice as likely to occur.

Why would global warming lead to more precipitation? According to study co-author Myles Allen of the University of Oxford in England, warmer air holds more water.

Senior scientist Kevin Trenberth of the National Center for Atmospheric Research in Boulder, who was not part of either study, expands on this: "The water holding capacity of the atmosphere goes up with higher temperatures (and higher sea-surface temperatures), and so there is simply more moisture lurking around waiting to be caught up in any storm."

The effects of greenhouse gases on precipitation appear to be global: "Extreme precipitation is expected to increase almost everywhere in a warmer world, even though we expect reductions in mean precipitation in some locations and increases in others," reports Zwiers.

Overall, according to Zwiers, computer models suggest that the northern high latitudes will see the largest percentage increases in mean annual precipitation, and that the tropics will see the largest percentage increases in extreme precipitation.

"Damaging weather events have always happened since well before humans had any substantial influence on climate," says Allen. "This research allows us to quantify how rising greenhouse gas levels may be loading the dice in favor of certain events, such as the U.K. floods of 2000, and against other events."

However, climate scientist Jerry North of Texas A&M University, while praising the work, said he worried that the studies were making too firm a connection based on weather data that could be poor in some locations. More

 

Heat Wave In China

For the entire month of July and the first half of August, eastern China baked in a record-breaking heat wave. Nineteen provinces endured above-normal temperatures.

Shanghai broke its all-time record high three times in as many weeks. The current record—40.8 degrees Celsius (105.4°F)—was set on August 7, 2013. At least 40 people have died during the heat wave, including ten in Shanghai, according to the Xinhua news service.

During a heat wave, ground temperatures soar, particularly in urban areas where there are fewer plants to cool the ground with shade and evapotranspiration. Paved or metallic surfaces can become warm enough to cook food. These images show land surface temperatures as measured by two different satellites.

The image above shows temperature anomalies across China between August 5 and August 12, 2013, as observed by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite. Red areas are warmer than the long-term average for the week, while cooler-than-average temperatures are blue. While much of China was warm during this period, the worst of the heat wave was concentrated near the coast and in Tibet. This weather pattern is tied to a subtropical high-pressure system parked over southern China, according to the China Meteorological Administration.

Though miserable everywhere, the heat wave was likely worst in China’s cities, where manmade surfaces absorb heat during the day and cool slowly at night. As a result, cities are warmer during the day and slower to cool at night, making an extended heat wave more uncomfortable, and more deadly, in a city. The image below shows this “urban heat island” effect in Shanghai.

The image was made with measurements taken on August 13, 2013 by the Thermal Infrared Sensor on the Landsat 8 satellite. The warmest surfaces are yellow, while cooler surfaces are pink. The image shows pockets of very warm areas, particularly downtown, surrounded by cooler suburban areas. The dark purple dots are cold clouds.

Chinese officials have declared a weather emergency, warning residents to limit time outdoors. It is the first time the country has issued a weather warning for heat. China’s National Meteorological Center expected the heat to break sometime after August 15.

 

Atmospheric Warming Altering Ocean Salinity And The Water Cycle

A clear change in salinity has been detected in the world’s oceans, signaling shifts and acceleration in the global rainfall and evaporation cycle tied directly to climate change.

In a paper published … in the journal Science, Australian scientists from the Commonwealth Scientific and Industrial Research Organisation (CSIRO) and Lawrence Livermore National Laboratory reported changing patterns of salinity in the global ocean during the past 50 years, marking a clear symptom of climate change.

Lead author Paul Durack said that by looking at observed ocean salinity changes and the relationship between salinity, rainfall and evaporation in climate models, they determined the water cycle has become 4 percent stronger from 1950-2000. This is twice the response projected by current generation global climate models.

“These changes suggest that arid regions have become drier and high rainfall regions have become wetter in response to observed global warming,” said Durack, a post-doctoral fellow at Lawrence Livermore National Laboratory.

Scientists monitor salinity changes in the world’s oceans to determine where rainfall has increased or decreased. “It provides us with a gauge — a method of monitoring how large-scale patterns of rainfall and evaporation (the climate variables we care most about) are changing,” Durack said.

With a projected temperature rise of 3 degrees Celsius by the end of the century, the researchers estimate a 24 percent acceleration of the water cycle is possible.

[JR: Actually the projected warming by century's end is closer to 5°C -- see review of literature here -- which would yield a stunning 40% acceleration of the water cycle.]

Scientists have struggled to determine coherent estimates of water cycle changes from land-based data because surface observations of rainfall and evaporation are sparse. According to the team, global oceans provide a much clearer picture.

“The ocean matters to climate — it stores 97 percent of the world’s water; receives 80 percent of all surface rainfall, and it has absorbed 90 percent of the Earth’s energy increase associated with past atmospheric warming,” said co-author, Richard Matear of CSIRO’s Wealth from Oceans Flagship.

“Warming of the Earth’s surface and lower atmosphere is expected to strengthen the water cycle largely driven by the ability of warmer air to hold and redistribute more moisture.”

He said the intensification is an enhancement in the patterns of exchange between evaporation and rainfall, and with oceans accounting for 71 percent of the global surface area, the change is clearly represented in ocean surface salinity patterns.

In the study, the scientists combined 50-year observed global surface salinity changes with changes from global climate models and found “robust evidence of an intensified global water cycle at a rate of about 8 percent per degree of surface warming,” Durack said.

Durack said the patterns are not uniform, with regional variations agreeing with the ‘rich get richer’ mechanism, where wet regions get wetter and dry regions drier.

He said a change in freshwater availability in response to climate change poses a more significant risk to human societies and ecosystems than warming alone.

“Changes to the global water cycle and the corresponding redistribution of rainfall will affect food availability, stability, access and utilization,” Durack said.

Susan Wijffels, co-chair of the global Argo project and a co-author on the study, said maintenance of the present fleet of around 3,500 profilers is critical to observing continuing changes to salinity in the upper oceans. More

This piece of research was originally published at the Lawrence Livermore National Laboratory.