Where have all the people gone?

There was a time when the crumbling towers around me held people. 

The world was a much different place, then.  SFIt was a time when the deserts of Braska and Gowga were verdant fields, when the rains fell in just the right amounts at just the right time, when people soared like eagles in their metal sky-kites and walked the streets now below my keel.   They say men even crossed across the then-frozen Sea of Northern Lights from Canda to Rusha on sleds pulled by dogs over the ice.  Some even say that people once went to the Moon and trod its surface (Oh, the things some people say!).  The fields, the rains which watered them, the sky-kites, the city below me and the people who lived then, all gone now.

That was before the world changed.  Sorry, that wasn’t quite right.  Before WE changed the world.  Before we knew that the way people lived back then, the lifestyle they led, came at a price.  A price that would end up being paid in human blood.  What they didn’t realize then was the tiny byproducts of their energy sources, the carbon, accumulated in the air, the water and the soil.  Not a lot, but enough to change things.

It happened slowly, at first.  Nights stayed a little warmer, the autumns would last a little longer, the winters would start a little later, spring would come a little earlier.  Not every year, but more and more, the seasons changed.  The great ice in the North was the first to yield, they say.  The thick crust covering the Sea of Northern Lights, the Arctic they called it, thinned.  Eventually it melted in summer, only to regrow in winter.  But each winter it was less than the last and soon it was gone.

The once-frozen ground in Canda and Rusha turned soft, like warm butter, yielding up vast stores of even more carbon.  Greenland’s great glashurs stirred to life, flooding the sea with immense blocks of ice the size of mountains.  And soon the Land at the Bottom of the World began to stir.  They say its Western part, the Wace, slid into the sea in the lifespan of a man.

The world-ocean began to rise, reaching hungrily for the works of man.  Man fought back, building great walls to keep the wolf at bay.  But soon the rising tide proved too much.  And one-by-one, the great cities of the coast, like the one under me, Myame, were left to their end.

The forests, once vast (before man a squirrel could travel from sea-to-sea via branch and vine without stepping paw on the ground), finally succumbed to timbering, drought, pestilence and disease, yielding their own carbon.

The fields dried, producing less food.  The rains, when they came, fell in great cloud-bursts, washing away the best soils for crops.  Food, once abundant, became scarce.  Mankind began to quarrel over what was left.  No one knows who started it, but war came.  First in skirmishes, then great battles were fought.  The number of man, once almost beyond count (it is said men could walk 4 abreast in rank and file around the entire world and the line would never end), began to dwindle.  And the Bombe itself was used, repeatedly.

The world, once home to billions, now barely supports not much more than once lived in the city below me.  For the oceans were also changed by the tiny carbon, becoming wet deserts with little life.  Sometimes the sea itself turns red like blood.  This event, once rare, is happening more often, now.  And the waters of the Sea of Northern Lights bubble and boil...

(MP3 rendition of the Intro to this article.  Self-recorded using Audacity)

While the above is a work of fiction, studying what the effects of climate change and sea level rise will have on human populations is not.

Identifying the human impact of rising sea levels is far more complex than just looking at coastal cities on a map. Rather, estimates that are based on current, static population data can greatly misrepresent the true extent — and the pronounced variability — of the human toll of climate change, say University of Wisconsin-Madison researchers.

"Not all places and not all people in those places will be impacted equally," says Katherine Curtis, an assistant professor of community and environmental sociology at UW-Madison.

In a report published in the peer-reviewed journal Population and Environment, Curtis and her colleague Annemarie Schneider examine the impacts of rising oceans as one element of how a changing climate will affect humans. "We're linking economic and social vulnerability with environmental vulnerability to better understand which areas and their populations are most vulnerable," Curtis says.

They used existing climate projections and maps to identify areas at risk of inundation from rising sea levels and storm surges, such as the one that breached New Orleans levees after Hurricane Katrina, then coupled those vulnerability assessments with projections for future populations.

It's a deceptively challenging process, the authors say. "Time scales for climate models and time scales for human demography are completely different," explains Schneider, part of the Center for Sustainability and the Global Environment at UW-Madison's Nelson Institute for Environmental Studies. "Future climate scenarios typically span 50 to 100 years or more. That's unreasonable for demographic projections, which are often conducted on the order of decades."

The current study works to better align population and climate data in both space and time, allowing the researchers to describe social and demographic dimensions of environmental vulnerability.

The analysis focuses on four regions they identified as highly susceptible to flooding: the tip of the Florida peninsula, coastal South Carolina, the northern New Jersey coastline, and the greater Sacramento region of northern California, areas that span a range of population demographics. (New Orleans was not included as a study site due to major population changes since the 2000 census.)


Figure 1.  Maps of the four study areas examined in this research: a Northern California, b New Jersey, c South Carolina, and d Southern Florida. The counties of each sample area are shown in dark green, while potential inundation is shown in orange (1-m sea-level rise) and red (4-m sea-level rise). For reference, urbanized areas are shown in yellow

With help from the UW-Madison Applied Population Laboratory, the researchers used 2000 census data and current patterns of population change to predict future population demographics in those areas. By 2030, they report, more than 19 million people may be affected by rising sea levels just in their four study areas.


Figure 2.  Observed and estimated population in 2000, 2008, and 2030 for the four study areas impacted by sea-level rise in 2030

And many of those people may be in unexpected places. The case studies clearly reveal the importance of considering people's patterns of movement.

"No area is completely isolated, and migration networks are one of the ways we think about connections across places. Through these networks, environmental impacts will have a ripple effect," Curtis says.

In one example, if Florida floods, New York and Los Angeles will feel the effects — in 2000, 14,000 people from three New York counties and another 5,500 from Los Angeles moved to Miami-Dade County, Fla. Under the environmental scenarios in the study, those people would have to remain where they started or move elsewhere, consequently shifting their resources and needs to new sites.


Figure 3.  Population projections in 2030 for the four study areas based on three net migration scenarios (growing economy, declining economy, and natural disaster)

Curtis and Schneider designed their approach with an eye toward helping local authorities identify and best respond to their own needs.

"Adaptation and mitigation strategies are developed and implemented at a local level. Part of the problem with large-scale population and environmental impact estimates is that they mask the local variation that is necessary in order for a local area to effectively respond," Curtis says.

A population's demographic, social, and economic profile affects the ways in which people can respond to local disaster, she adds. For example, children or elderly require a different approach to evacuation and resettlement than a largely working-age population, while workers from the agricultural lands of northern California will face different post-displacement labor challenges than those from the industrial corridor of New Jersey.

Even using rough estimates of sea level rise, their analysis makes clear that planning ahead for mitigation and adaptation will be crucial, Schneider says.

"As we anticipate future events, future natural disasters, we've learned how dramatic it can be — and there are things that can be done in advance to mitigate the extent of damage in a location," Curtis says.


Where have all the people gone, long time passing?
Where have all the people gone, long time ago?
Where have all the people gone?
Gone to graveyards, everyone.
Oh, when will they ever learn?
Oh, when will they ever learn?

Posted by Daniel Bailey on Tuesday, 9 August, 2011

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