Sea Level Rise, Persistent Drought Sets off Mass Migration and Famine in Pakistan

Both surface water and ground water have become unusable, with the once fertile Indus river basin turning into a desert, as sea water brings sand inland as far as 50 kilometers.World Bulletin in June of 2014

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For the cities, towns and villages of Sindh Province along the Indus River in Southeast Pakistan, the seas are rising and the winter rains have failed. It is a place besieged on all sides by climate change. By forces that are killing its children due to malnutrition and turning tens of thousands of its populace into climate change refugees.

Coastal Villages in Pakistan Retreat Ahead of Rising Seas

(Coastal villages in Pakistan retreat ahead of rising seas. Image source: Ali Murtaza)

Climate Change, Loss of Trees, Loss of Children

A combination of rising temperatures and decimation of local forests due to gum extraction has exacerbated an extraordinary moisture deficit for an already arid region. In early spring of 2014, the impacts to crops resulted in scores of children dying due to malnutrition. By late fall, the famine had returned with increased intensity, resulting in the loss of nearly 300 children in less than three months. A tragic loss that may well have been avoided.

Increased aridity in the region can be blamed on a number of factors — all related to human-caused climate change. Gum extraction from Gugral trees has resulted in losses of up to 70 percent from local stands. The loss of these tens of thousands of trees has, in turn, resulted in less water retention kicking off increased aridity. Meanwhile, larger global climate change is resulting in higher temperatures over the region — increasing evaporation rates and further lowering soil moisture content. Glacier loss in the Himalayas has recently pushed a surge of added water down the Indus — which helped to boost development unsustainably. Now glacial outflows are at risk of dwindling, threatening the long-term future of the Indus itself. Finally, the increasing global heat is kicking off alterations in seasonal rain patterns — making the winter rains less reliable.

Sea Level Rise Ruins Coastal Crops, Sets off Mass Migration

The combined factors would be difficult enough for Sindh and its cities to manage. But a final factor appears to be delivering another disruptive coup de grace. As of mid 2014, environmental reports had indicated a mass migration away from Pakistani coastal regions.

Indus Delta

(Not a cloud above the once-fertile but now increasingly salt-ridden Indus Delta on 14 January 2014. Image source: LANCE-MODIS.)

Rising seas had resulted in increasing levels of salt water in near-coast aquifers and wetlands. The rising salt levels in soils made irrigation of coastal crops impossible in many regions. Within just a few years, the elevated seas had rendered 1 million hectares of land arid — making it impossible for farmers to grow crops or to raise animals.

According to a June 2014 report by World Bulletin:

Both surface water and ground water have become unusable, with the once fertile Indus river basin turning into a desert, as sea water brings sand inland as far as 50 kilometers.

In addition, saltwater invasions of the Indus river reduced fish stocks. This sudden loss of water useful to agriculture and precipitous fall in fish stocks suddenly put many farmers and fishermen out of work.

By mid 2014, more than 100,000 people had fled the coast. Now, these tens of thousands of jobless farmers and fishermen pack the streets of inland towns — seeking jobs and places to live that simply may not be available.

But what this litany of harsh statistics doesn’t tell is how many of the children lost came from families of those displaced by rising seas.

Sadly, this issue of river deltas losing fertility to the inexorably rising tide is not just a problem for Pakistan. Many of the worlds most productive agricultural zones lie in delta regions. At this point, all are under threat due to speeding sea level rise set off by rising rates of glacial melt. And as we have seen in Brazil, California and Pakistan this year other increasing atmospheric temperatures, climate induced weather pattern changes and deforestation (Brazil, Pakistan) also play a role.

Links:

Rising Seas Force 100,000 Pakistanis From Coastal Homes

Another Child Dies of Famine in Tharparkar Due to Malnutrition

Sindh Region of Pakistan

Famine Hits Thar

Thousands of Trees Lost in Thar

LANCE-MODIS

Glacial Melt Will Reduce Crucial Water Supplies

Hat Tip to Colorado Bob

Hat Tip to Andy in San Diego

Hat Tip to Planet in Danger

It’s All About Fresh Water — Rapid Sea Level Rise Points To Massive Glacial Melt in Antarctica

It’s all about fresh water. In this case, massive freshwater outflows from the vast glaciers covering Antarctica.

This week, a new scientific report published in the Journal Nature found that from 1992 through 2012 freshwater outflow from Antarctica’s massive glaciers exceeded 400 gigatons each year. An immense flood of cold, fresh water. One that helped push sea levels rapidly higher around the Antarctic continent.

But with glacial melt on the rise and with mountains of ice now inexorably sliding seaward, these freshwater flows may just be the start of even more powerful outbursts to come. And such prospective future events have far-ranging implications for sea level rise, global weather, sea ice, human-caused climate change, and world ocean health.

Flood of Fresh Water Drives More Sea Level Rise Than Expected

The researchers discovered the tell-tale signature of this vast freshwater flood through chemical analysis of the seas surrounding Antarctica. The analysis pointed to a broad and expanding fresh water layer over-riding a warmer, saltier current issuing in from the Southern Ocean.

Since fresh water is less dense than salt water, the freshwater layer expands at the ocean surface causing sea levels to rise more rapidly. Meanwhile, the heating of the deep ocean surrounding Antarctica is thought to result in additional thermal expansion of the water column.

The researchers note:

On the basis of the model simulations, we conclude that this sea-level rise is almost entirely related to steric adjustment [changes that effect atomic spacing], rather than changes in local ocean mass, with a halosteric [salt based] rise in the upper ocean and thermosteric [heat based] contributions at depth. We estimate that an excess freshwater input of 430 ± 230 Gt yr−1 is required to explain the observed sea-level rise. We conclude that accelerating discharge from the Antarctic Ice Sheet has had a pronounced and widespread impact on the adjacent subpolar seas over the past two decades.

Antarctic Sea level Trend

(Rate of sea level rise in the seas surrounding Antarctica since 1992. Aggregate sea level rise is indicated in black. Individual seas data is broken out by color. Image source: Nature.)

Previously, increased rates of sea level rise surrounding Antarctica were thought to have been set off by increasing winds around the continent. The winds were thought to push more water up against the ice faces forming a kind of perpetual, low-grade storm surge. But the current finding provides strong evidence that the source of the sea level rise is due to less dense fresh water over-topping saltier waters flowing in from the Southern Ocean combined with increasing heat along the Antarctic sea bed. And, notably, this is not the first study to find increasing freshwater flows spilling into the Southern Ocean. Last year, a KNMI expedition uncovered similar results.

More Evidence of Large-Scale Melt

The study comes on the back of other recent findings showing that warm water invasion at Antarctic glacier bases had led to more rapid than expected melt and destabilization. In May, two NASA studies showed that a broad section of West Antarctica had destabilized and was sliding at an ever more rapid pace toward the ocean (see reports here and here). These findings held stark implications for global sea level rise as large ice regions of Greenland and West Antarctica, containing enough water to raise seas at least 15 feet, are likely already in a state of irreversible collapse.

 

Regional Anomaly Sea level Antarctic

(Sea level rise anomaly of the region surrounding Antarctica compared with the rest of the Southern Ocean. Red indicates faster than normal sea level rise. Blue indicates slower than normal sea level rise. Image source: Nature.)

This intensifying glacial melt and associated freshwater cap expanding out from the pole has implications — not just for sea level rise, but for sea ice, weather, and world ocean system health.

Impacts For Sea Ice

Large outflows of glacial fresh water may well be involved in the recent observed expansion of sea ice in the zone surrounding Antarctica (see recent related study). Fresh water serves as an insulative cap on the ocean surface preventing warm water from entering the top layer from below. The warm, salty water, in the Antarctic instead pools near the bottom or at the base of the great ice sheets.

Fresh water also freezes at a higher temperature than salt water. So sea ice in an expanding freshwater zone around Antarctica would have naturally higher resiliency even to the rising temperatures now occurring due to human-caused warming. Eventually, however, human heat forcing would overwhelm the ice, but not before a period of related, localized negative feedbacks.

The Iceberg Cooling Effect

The fresh water is a haven for sunlight-reflecting sea ice. It is interspersed with ice bergs from the glacial discharge and the large ice bergs cool the surrounding air. The fresh water layer prevents warm water upwelling from the warm, deep waters surrounding Antarctica. And the leading edge of the fresh water would drive salt-water down-welling along its advancing front. This would push warmer waters toward the ocean bottom, resulting in a kind of heat sink. And this is exactly the kind of dynamic that appears to be ongoing in the Southern Ocean now. These combined impacts are what is known as the ice berg cooling effect associated with large-scale glacial outbursts known as Heinrich Events. And we may well be in the process of setting off one of these geological scale nightmares.

20121230_iceberg_cooling_effect_Hansen_Sato

(Iceberg cooling effect under a mid-range warming scenario when global climate models were set to include the effects of large freshwater outflows from polar glaciers at a fast enough rate to raise seas by 60 cm through 2060 and 144 cm through 2080 [left frames]. Note the cooler zones in the Southern Ocean and North Atlantic adjacent to Greenland. Right frames include mid range emissions/warming scenarios and IPCC projected rates of sea level rise. It is worth noting that the amplifying effects of potential additional ghg release from the global climate system, particularly from Arctic and world ocean carbon stores, are not included in these simulations. Image source: Hansen and Sato.)

For global weather, such events have major implications. Regional cooling in the zone of freshwater outflow would juxtapose regional warming in the southern hemisphere meridional zones. This temperature differential would increase with the strength of the fresh water outflow and the rising intensity of the human-driven warming. The result would be a powerfully intensified storm track. Both the intensified storm track and increased atmospheric moisture loading due to human warming would result in much more powerful weather events than we are currently used to and the potential for catastrophic storms would drastically increase.

Amplifying Feedbacks and a Blow to World Ocean Health

Lastly, the expanding flood of fresh water would result in an increasing stratification of the world ocean system. This stratification would drive warm, salty water toward the ocean bottom and deplete already low oxygen reserves in that region. In addition, the extra heat is more likely to destabilize deep-sea clathrates — releasing methane which will speed in the oxygen depletion of the abyssal waters even as it tips the world ocean system to stop storing carbon and to begin releasing it. A combined feedback that is both an ocean killer and an amplifier to the already extraordinarily powerful human heat forcing mechanism.

Links:

Rapid Sea Level Rise Along Antarctic Margins Due to Increasing Glacial Discharge

Important Role For Ocean Warming and Enhanced Ice Shelf Melt in Sea Ice Expansion

Update on Greenland Ice Sheet Mass Loss: Exponential?

Grim News From NASA: West Antarctica’s Entire Flank is Collapsing

Nature: Human-Destabilized Antarctica Capable of Glacial Outbursts Contributing to Up to 14 Feet of Sea Level Rise Per Century

 

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