Tuesday, November 27, 2012

Cascadia's Fault: The Coming Earthquake and Tsunami That Could Devastate North America - Jerry Thompson

First Nations peoples of the Pacific Northwest have passed down stories for generations about a winter’s night when the ground shook terribly and an enormous wave hit the coast and wiped out entire communities. The Europeans who began to populate this region in the 1800s did not pay attention to these stories, nor did few others until the mid to late 20th century when it turned out that these First Nations stories were rooted in fact, and that this part of North America was not a special aseismic region of the Ring of Fire. “Cascadia’s Fault” is the story of the decades-long multi-disciplinary search that led to the scientific evidence and conclusion that one day in the future the Pacific Northwest will be struck by another devastating earthquake.

Journalist Jerry Thompson begins the story of the search for the Cascadia Fault by explaining where it started. For a long time earth scientists and residents believed that because the region from the north end of Vancouver Island to the Oregon-California border had been essentially tremblor-free in all of recorded history (since European contact), because there was no obvious fault line or trench, it was assumed that the two tectonic plates were moving smoothly past each other and there was no danger to the region. It was the 1985 earthquake in Mexico City that got West Coast geologists questioning whether this theory was correct as the fault off the west coast of Mexico was also deemed aseismic…and was very similar to Cascadia, except shorter.

This questioning led researchers back to 1964 when a tsunami hit the small Vancouver Island town of Port Alberni after the 9.2 megathrust quake in Prince William Sound off the Alaskan coast. There were incredible changes to the region: an area the size of the states of Washington and Oregon combined had heaved up or dropped down, the sea floor appeared to have lifted more than 15m, and the land also stretched horizontally up to 20m between the city of Anchorage and the edge or Prince William Sound. This quake was surprising because after it happened no one was able to say which fault had ruptured and why this fault had gone undetected for so long. However, because the scientists studying this earthquake were doing so just at the time that the theory of plate tectonics was becoming more popular, it took many years for scientific conclusions about the geology of the region to be accepted: that off the West Coast of North America were subduction zones (horizontal cracks in the earth’s crust).

All of this led scientists back to searching for clues along the Washington and Oregon coast that might shed light on the seismic history of the Cascadia fault. The remainder of the book concentrates on this research. Thompson describes how surveying engineers had set up geodetic markers on mountaintops and were using lasers and GPS co-ordinates to determine whether or not there was any movement in the peaks. There was – the mountains of Vancouver Island were being squeezed landward, towards the mainland, about 20cm in less than 40years. Hundreds of kilometres worth of mountain rock were being pushed horizontally yet even then selling the idea that a subduction zone was locked and building up energy for a future earthquake was difficult. More evidence was needed to show that there was plate tectonic activity here and that it had led to past earthquakes.

Thompson then introduces two Washington scientists: Brian Atwater and David Yamaguchi. Atwater, in 1986, discovered what he calls the ghost forest not long after his discovery of another region northwest of Seattle that showed layers of sea sediment and plants above layers of land sediments and plants:

This was no gentle or gradual transition zone from one geologic era to another. The peat had a sharp upper boundary caused by an almost instantaneous and probably cataclysmic change in the level of the land and sea. Was it physical proof that the ground had slumped during an earthquake, that the plants of a marsh or forest meadow had been drowned quite suddenly by the incoming tides and possibly buried under the sands of a huge tsunami?

Good question, and the ghost forest raised another that tree scientist David Yamaguchi attempted to answer: when did this forest end up swamped by salt water, killing the spruce trees? By studying the tree rings, Yamaguchi managed to narrow the timeframe for the last earthquake along the Cascadia Fault to sometime between 1680 and 1720. Despite cutting and counting rings on both dead and witness trees (those living at the time the others died), Yamaguchi could get no closer. However, in 1994 a Japanese geologist who specializes in subduction zone and tsunami research, Kenji Satake, learned of these dates and their association with an earthquake and was immediately intrigued. While North America did not have written records at that time, Japan did, and it was in those records that Satake made an amazing discovery. In historical documents found in four separate town there was mention of a 5m tall tsunami in 1700, and the only place it could have originated was from the Cascadia fault. By calculating backward, the quake was estimated to be at least magnitude 9. They were also able to calculate even more. As Satake wrote in Nature:

The earliest documented tsunami arrival time was around midnight on 27 January, Japan time. Because tsunami travel time from Cascadia to Japan is about 10 hours, the earthquake origin time is estimated at around 5:00 on 27 January GMT or 21:00 on 26 January local time in Cascadia. This time is consistent with Native American legends that an earthquake occurred on a winter night.

Finally, by 1997, it became a known fact that Cascadia is an active fault whose next rupture would have major consequences for at least five North American cities. This is why Thompson’s book is so important. This information is barely 15 years old but has already been taken seriously, but perhaps not yet seriously enough because there just seems to be no reliable way to predict when an earthquake will hit. There have been some efforts to make BC, Washington and Oregon earthquake disaster ready, but there is still a long way to go to both raise public awareness and emergency response standards to a level that would be able to deal with events on the scale of the 1995 Kobe quake and the 2004 Sumatra tsunami.

Every person in the Pacific Northwest should pick up this book and both enjoy the history and explanations written in an interesting and accessible manner for even those with the most minimal knowledge of geology, as well as the implicit and explicit warnings that it has happened before and will happen again, so we had better be prepared.

Emergency Management BC website with information about earthquake preparedness: http://embc.gov.bc.ca/em/hazard_preparedness/earthquake_preparedness.html

Saturday, November 17, 2012

Locavore: from farmers’ fields to rooftop gardens – how Canadians are changing the way we eat - Sarah Elton

Sugary processed foods full of cheap calories linked to increasing rates of obesity and diabetes. Fruits and vegetables whose durability for traveling long distances is more important than their flavour and nutrition. The environmental cost of using fossil fuels to ship food worldwide. The ability to provide food security to a population. These are a few of the issues Sarah Elton explores in her book Locavore as she argues for sustainable local food systems.

It was a plastic-wrapped pig cookie covered in pink icing with the words “Made in China” at the end of its list of ingredients that led Elton to question just what was happening to Canada’s food supply system. While thousands of Canadians accept that year round there will be all types of exotic fruits and vegetables in the stores, she found it disturbing that foods were being imported that could be easily made locally.

Elton began asking questions and got some surprising statistics in return. Newfoundland grows less than 10 percent of what it eats. Vancouver Island used to produce 85 percent of the food it needed, but that has dropped to 10 percent as well. Industrial agriculture has allowed a modern farm to, per hour of labour, produce 350 times more food than a subsistence farmer would have produced on the same soils. A large amount of the food that feeds Canadians is imported because it is cheaper to produce elsewhere.

Elton argues that every country should be able to feed itself through a sustainable local food system, arguing: “Drought in some parts of the world is devastating crops, while storms cause extreme flooding in other regions. If turbulent weather or a severe drought caused grain or rice crops to fail around the world, millions of us would starve.” She also questions what would happen if trade routes were to shut down due to war, environmental destruction, or petroleum shortages and rising transport costs.

One issue Canada would face in a local food system is climate. Elton visited what she calls “four-season farms” in Ontario where many farmers are innovating greenhouse agriculture. Greenhouses can be incredibly productive, producing 600 000 pounds of food per acre per year when a single outdoor acre will produce 90 percent less food since it can only produce one crop a season. While greenhouses use a lot of energy for grow lights, the majority of the energy demand is for heat – the energy coming primarily from electricity or coal. Some local greenhouse farmers have found that they can reduce the need for electricity or fertilizer inputs for their crops simply by changing planting times, developing hardy varieties, and using innovative methods such as aquaponics (combining fish farms and greenhouse gardens) which both conserves water and provides nutrient inputs for the crops.

Mike Shreiner, leader of Ontario’s Green Party and sustainable food system advocate, says, “We have the technology and the capacity to operate greenhouses in environmentally friendly ways. Now, whether the marketplace allows us to do it on a cost basis is to be seen.” The vagaries of the economy is always a major risk, and, as Elton points out, “no greenhouse is sustainable unless it is economically viable” so as long as imported produce stays so cheap, Canadian greenhouse growers have little chance of contributing to a local food system.

It is this same market system that put pressure on Canadian farms in the 1970s and 1980s as first the oil crisis and then a glut in the world food market meant that farms were no longer making enough money to pay the debts incurred as they rushed to expand the size of their farms during the boom years. Thousands of farmers went bankrupt, and farming in Canada never recovered. Farming is no longer the profitable industry it once was, and fewer are entering the profession today. There are fewer farmers than ever trying to feed the largest urban populations ever. Those who have stayed in farming are forced to become innovative business thinkers, and are finding ways to be successful enough to continue.

Donald and Viola Daigle are from New Brunswick and their family farm is part of the Really Local Harvest Co-op, which has been credited with saving many farms in the area. As farmers struggled to find stores and restaurants to stock their produced, often selling at a loss, a group decided to work together (instead of competing) to sell their crops directly to the consumer. The co-op developed a mandate whereby members assist each other to increase profits while selling an ecologically sustainable product at a fair price. As well, no member farmer is permitted to sell at a loss. Over time, the co-op’s success grew as the community realized they were getting a better product from the local farmers than the non-local produce at the stores: it was higher quality, better tasting, and that made it worth the extra cost.

Larry Yee of the Association of Family Farms in California describes organizations like the Really Local Harvest Co-op as attaching worth to qualities beyond money, “You are producing a different food product that has qualities people are looking for.” Elton argues that food is a personal issue and “by making consumer choices that support the creation of a sustainable local food economy, we are helping to create solutions” and perhaps to “create a new food order”.

It might seem simple enough to “vote with our forks” but the effect this has on the global system of industrial agriculture is small. There is nothing wrong with Elton’s advice to shop from farmers markets from local farmers, to buy organic and fair trade, or even to simply avoid purchasing processed foods. However, these cannot be the only thing people do, and are often only possible by those with higher incomes anyway. Buying flour made from locally grown grain will not stop the worldwide overproduction of grain, nor will buying locally grown corn stop the proliferation of processed foods made from the excess corn. As long as farmers must continue to struggle to make a profit it is unlikely that a truly sustainable food system can be developed. That said, Elton’s book is engaging and readable, and gives hope and ideas for the future of the world’s food systems.

Sunday, November 4, 2012

The Sea Around Us - Rachel Carson

The namesake river of this blog – the Fraser River – is the largest watershed in the province of British Columbia, eventually emptying into the Strait of Georgia 1375km from its headwaters. From there, the river water becomes part of the vastness of the oceans. So few of us have traveled beyond a few kilometres from the shore; even fewer have crossed the ocean by ship. Often our only view of the centre of an ocean is from an airplane. As such, oceans remain places of mystery, inspiring stories of monstrous creatures living in the cold dark deep while challenging scientists to find ways to study their depths.

Rachel Carson was enamored of the mystery of the oceans. “The Sea Around Us”, published in 1951, is the second in what is known as her sea trilogy. It is a collection of 14 chapters, some of which were published as standalone articles in prominent magazines such as The New Yorker and Nature Magazine. As a result there is not a single narrative throughout the book; rather the chapters are organized into 3 parts based on themes within. Part 1 explores the origins of the sea, part 2 the movement of water, and part 3 the relationship between humans and the oceans.

Carson’s science writing style is poetic and accessible, and she is able to use this alongside the scientific language to draw casual readers into the oceanography and make them care about the water, rocks, winds and tides. Her style is unique, and of a quality rarely seen in scientific writing today. In the section titled “The Changing Year”, which describes what happens in the ocean through the course of the seasons, she writes:

The larvae of the bottom fauna have long since completed their development and drifted away to take up whatever existence is their lot. Even the roving fish schools have deserted the surface waters and have migrated into warmer latitudes or have found equivalent warmth in the deep, quiet waters along the edge of the continental shelf. There the torpor of semi-hibernation descends upon them and will possess them during the months of winter.

Another thing that makes “The Sea Around Us” so interesting is that, having been published in 1951, many of the oceanographic discoveries Carson writes about were relatively new to her and to science. Unlike Earth’s surface, the majority of which is easily observable, the ocean is not. The pressure of tonnes of water coupled with utter darkness makes deep sea exploration difficult (and expensive). It was only in the 1920s and later that remote sensing technologies developed to a point that the crust in ocean basins could be accurately studied. For example, in the section titled “Hidden Lands”, Carson speculates:

One of the most fascinating fields for speculation is the age of the submarine mountains compared with that of past and present mountains of the continents…What of the sea’s mountains? Were they formed in the same way and do they, too, begin to die as soon as they are born?

The reason for this speculation stems from the fact that the mechanism of sea floor spreading had not been fully developed and explored until the 1950s and 1960s, after the publication of this book (and, in fact, after Carson’s death). We now know that ocean crust is created at mid-ocean ridges, and destroyed in the trenches near to the continents. As for the age of the oceanic crust, it is much younger than the Earth itself and much of the continental shelf – only around 200 million years old.

Or how later, in “Wind and Water”, Carson mentions the 1946 earthquake in Alaska’s Aleutian islands that caused a tsunami in Hawaii, a connection that up to this time was still not fully understood. However, it was after this quake that Carson says “it set people to thinking that perhaps we now know enough about such waves and how they behave that a warning system could be devised”. The United States Coast and Geodetic Survey then developed the method to pinpoint an offshore earthquake’s epicentre and predict the path of a potential tsunami so that communities could prepare. This warning system was used locally as recently as two weeks ago when a 7.7 magnitude earthquake was detected off Haida Gwaii, and within minutes both cities as near as the BC coast and as distant as Hawaii were on watch.

Perhaps the most interesting chapter to a modern day reader would be “The Global Thermostat”, an explanation of the connections between ocean currents, ocean temperatures and the climate of continents over the short and long term. To paint this picture, Carson provides examples of historical climate change from such sources as logs of Viking seafarers and Scandinavian fishers of the Middle Ages. Then she makes the following statement, which could have been written today:

Now in our own lifetime we are witnessing a startling change in climate…it is now established beyond question that a definite change in the Arctic climate set in about 1900, that it became astonishingly marked about 1930, and that it is now spreading in sub-Arctic and temperate regions. The frigid top of the world is very clearly warming up.

The reasons Carson provides for this warming trend include the possibility that Earth is still in a warming trend following the last Pleistocene glaciation, and changes in solar radiation or in tide patterns. It makes sense that natural variation can account for some warming, but since the time the book was written there has been an exponential increase in the rate of warming, primarily due to human factors increasing the amount of carbon dioxide in the atmosphere: burning fossil fuels, ozone depletion, deforestation. If Carson was alive and writing “The Sea Around Us” today, she would most likely have included a discussion of these factors as they would have fit with her ecological philosophy.

“The Sea Around Us” remains relevant 60 years after its original publication despite advances in oceanographic research that make some aspects of the book dated. Through her evocative descriptions that interweave history with literature with science, Carson shows how the importance of the oceans to life on the continents cannot be ignored. This book is a strong reminder that the fight for a sustainable lifestyle that minimizes carbon dioxide emissions into the atmosphere and rubbish disposal into the oceans will never cease to be necessary.