Case Study: the Aral Sea

Today's post on the Aral Sea slightly deviates from the topic of food, but because it is one of the most catastrophic examples of the environmental impacts of intensive agriculture, I thought it deserved a place on this blog. So let's begin...

Abandoned boats scattered across desiccated areas
of the Aral Sea (Photo by Audun Kjørstad)

The Aral Sea, a large saltwater lake shared between Kazakhstan to the north and Uzbekistan to the south, was once the world's fourth largest body of inland water behind the Caspian Sea, Lake Superior, and Lake Victoria (Micklin, 1988). The Aral Sea drainage basin covers 1.8 million km² within seven nations, and is a terminal lake, i.e. it has surface inflow but no outflow (Micklin, 2006). It has experienced dramatic desiccation during the 20th century as a result of the diversion of riverine waters for agricultural irrigation from the Syr Dar'ya and the Amu Dar'ya starting in the 1960's. The Syr Dar'ya and the Amu Dar'ya are the main sources of water to the Aral Sea, and by the 1980's, these two rivers virtually dried up (Encyclopaedia Britannica, 2014).

The Aral Sea basin (Micklin, 2006)

Until 1960, the Aral Sea was a brackish lake (mean salinity of 10 g/L) that was inhabited by freshwater species. It supported a major fishery and was also used as a regional transportation route. In addition, the deltas of the Amu Dar'ya and the Syr Dar'ya supported rich bioligical diversity as well as activities such as irrigated agriculture and animal husbandry, among others (Micklin, 2006). It is interesting to note that the Aral Sea has been repeatedly flooded and desiccated throughout the Pliocene, the most recent replenishment occurring during the Pleistocene around 140,000 years ago. Over the past 10,000 years, fluctuations in the Aral Sea's surface level ranged from 20 to 40m as suggested by evidence such as marine fossils, archaeological sites and the like (Micklin, 1988).

Average annual water balance for the Aral Sea between
1911 and 2005 (Micklin, 2006)

What happened in 1960 that prompted the Aral Sea's tipping point? In the early days of the Soviet Union, communist authorities devised plans to increase the production of cotton, or white gold. Cotton production was increased in the 1920's, and by 1950 hundreds of kilometers of unlined canals from the Amu Dar'ya and Syr Dar'ya were carved into the surrounding desert to irrigate new cotton plantations (Stone, 1999). The effects of the rerouting of the two rivers were immediately felt, with major water deficits occurring by the 1980's, as can be seen from the above figure. Since 1960, the profile of the Aral Sea has been drastically modified due to this irrigation. Between 1987 and 1989, it was split into a "Small Aral Sea" in the north and a "Large Aral Sea" in the south. By 2005, the Large Aral Sea had become separated into three distinct bodies (Micklin, 2006).

Changes in the profile of the Aral Sea (Micklin, 2006)

So, why is all this important? The desiccation of the Aral Sea led to environmental impacts such as the loss of wetlands as a result of reduced river flow and the loss of fish species due to breeding ground destruction and increased salinity (Micklin, 2008). In terms of human impacts, the disappearance of the inland sea prompted the collapse of local fisheries, the end of shipping routes, and the exposure of a seabed rich in salt, pesticides, and other agricultural contaminants which can be transported by toxic dust storms (Micklin, 2008; Stone, 1999). Vozrozhdeniya (Resurrection) Island in the centre of the Aral Sea was once used as a ground for biological weapons testing. In 2001, the island was joined to mainland, creating a risk of human exposure to these weaponised organisms (Micklin, 2008). 

Resurrection Island (Micklin, 2008)

What's been done to alleviate the situation? In the 1990's, Kazakhstan attempted to restore the Large Aral Sea by constructing a dike to block outflow to the south, which was destroyed by a catastrophic failure in 1999. In 2005, however, a 13km earthen dike with a gated concrete dam for water discharge was installed with the aid of funding from the World Bank. This has led to an 18 percent increase in area of the northern portion of the Aral Sea, and fish are now being caught again in the area (Micklin, 2008). The Aral Sea has shown signs of restoration since then (e.g. Pala, 2011), and time will tell if the southern portion of the sea will one day reappear.

To conclude this post, I'm leaving you with this video of Bruce Pengra explaining how Landsat imagery has been used to document the Aral Sea's decline through time. It's truly amazing to see how the lake has transformed throughout the years. The disappearance of the Aral Sea is undoubtedly one of the great examples of global environmental change through time, and has taught humanity lessons on the effects of over-exploitation of natural resources from delicate ecosystems.

Thanks for reading!

Happy New Year, and a Recipe

Happy New Year dear readers!

I simply had to share this beautiful recipe with you because it just turned out so well. Behold, baked brie with cranberry sauce, toasted hazelnuts, and rosemary. You can find the recipe here at the Kitchn.

I hope you all had lovely New Year's Eve celebrations and are enjoying a relaxing first day of 2014. Thanks for reading my posts over the past few months, your comments and insights have been so interesting. Next up in 2014: the Aral Sea. Check back here in a few days time to learn about "one of the world's greatest environmental disasters" (Small et al., 2001).

GHG Emissions and Agriculture

In a previous post we touched on the livestock sector's impact on greenhouse gas (GHG) emissions. Today, let's examine GHG emissions from the agricultural sector as a whole.

Emissions from agriculture occur in the form of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). CH4 and N2O are the most important sources of GHG emissions from agriculture, the agricultural sector contributing over 50% of the total amount anthropogenic emissions of these gases (Cole et al., 1997). Between 1990 and 2005, agricultural emissions of CH4 and N2O increased by 17%, equal to a an average annual emission rate of increase of approximately 60 megatonnes of CO2 equivalent (MtCO2-eq) per year (IPCC, 2007).

Agricultural fields in Brazil as seen from space (source: the Guardian)

Agricultural lands occupy approximately 40-50% of the Earth's land surface (IPCC, 2007), and can be clearly seen from space (e.g. above photo). Food systems today are so important that they contribute between 19 and 29% of the world's human-induced GHG emissions. Together, agriculture and forestry account for as much as one third of global GHG emissions (CGIAR, 2012). In 2008, approximately 9,800-16,900 MtCO2-eq were released from agricultural practices, agricultural production (including land cover change) comprising 80 to 86% of all food system emissions (Vermeulen, 2012).

Global agricultural emissions (CGIAR, 2013)

Various stages in the food production system are responsible for GHG emissions, as can be seen from the diagram above. The main three stages in the production of food include preproduction, production, and postproduction. By and large, the production stage which includes both direct and indirect emissions from agriculture contributes the largest portion of emissions. Within these stages of the food chain, regional variations exists with high-income countries contributing most to the postproduction stage (Vermeulen, 2012). 

Thornton (2012) argues that the effects of climate change will greatly affect the agricultural sector, and examines 22 common agricultural commodities' responses in the face of climate change. He states that "the world's agricultural system faces an uphill struggle", and that it will become a great challenge to feed global populations (as we saw with Foley, 2009). He also finds that the production of the most common commodity crops (wheat, maize, and rice) will be challenged by new weather patterns, as will the raising of livestock and catching of fish (two of the more common sources of protein). The Telegraph recently reported on the fact that the UK is now an importer of wheat because of large swings in weather conditions, exemplifying Thornton's (2012) findings (you can read the article here).

The UK was forced to switch from being an exporter of wheat to an
importer in 2013 (from the Telegraph)

At this point in our examination of current food systems, I'd like to take a little journey backwards in time. Remember when we talked about the origins of agriculture in November? We saw that the advent of agriculture about 10,000 years ago greatly altered human societies, and also the environment. What we didn't talk about was the early anthropogenic hypothesis, proposed by Ruddiman in 2003. Contrary to the popular notion that the Anthropocene began 150 to 200 years ago, altering the climate system by inputting CO2 and CH4 at industsrial rates, Ruddiman suggests that this transition in fact occurred thousands of years ago when agriculture was born. His three main arguments are that a) CO2 and CH4 concentrations anomalously began to increase 8,000 and 5,000 years ago, respectively; b) published explanations exist for mid- to late-Holocene gas increases which reject natural forcing; and c) wide arrays of archaeological, cultural, historical, and geologic evidence are available which point to anthropogenic impacts from early agriculture (in Eurasia in particular). Ruddiman's hypothesis is often criticised (see Ruddiman, 2007), but I thought it was worth mentioning and this post seemed like a good venue.

Regardless of when agriculture began to impact the climate system, it is clear that global food production is greatly contributing to climate change by inputting large amounts of GHGs into the atmosphere. The great challenge will be to produce enough food to feed the growing world, but at what cost? How will we manage to do so without imposing great climate change threats? If you're interested in mitigation strategies, you can read about it in chapter 8.4 of the IPCC's Fourth Assessment Report (AR4).

Thanks for reading, and have a Happy New Year!

Indigenous Fruits and Vegetables

Today's post is a quick little aside before we go on to explore GHG emissions from the agricultural sector as a whole later on in the week...

I was leisurely browsing the online world of food news this afternoon and came across this interesting article in the Guardian. The title, Healthy eating: nutritious indigenous foods you may never have heard of particularly caught my eye given the festive holiday season. After having eaten my fair share of sweets and decadent foods over the past week (and surely for the next week to come), I tend to get overly enthusiastic when I see articles with the word 'healthy' in their titles! 

Perinaldo artichokes (source: the Guardian)

The article describes a list of indigenous fruits and vegetables created by Food Tank: The Food ThinkTank that could present healthier alternatives to modern-day staples. The rationale behind the creation of the list is that the Western diet, which is rich in refined sugars, fats, processed grain and meat has taken over the world over the past three decades (e.g. Bonhommeau et al., 2013). This dietary shift has been linked with increased chronic disease incidence, including obesity and cardiovascular disease (Cordain, 2005). Organisations, such as the World Vegetable Center, are working to catalogue these indigenous foods, because many have been replaced and even lost as traditional diets are being replaced by Western diets. 

Amaranth (source: the Guardian)

The list includes some well known indigenous fruits and vegetables such as amaranth and argan (Africa), artichokes (Europe), okra, mungbean and lemongrass (Asia), and apples (Americas), as well as many others which I'd never heard of before (such as papalo from the Americas, which has a skunk-like smell and is known to regulate blood pressure and relieve stomach disorders).

Given that we recently touched on the Western diet when we examined the livestock sector, I thought that sharing this article would be a nice little break from all the hard-hitting environmental facts surrounding our food system. I'll be back to discuss the very imposing issue of GHG emissions from agriculture in a few days' time, so do check back soon.

For those of you that have come to study in the UK from abroad, are there any healthy traditional foods that are being replaced due to the emergence of a Western diet? I can't think of any examples from Canada off the top of my head, but I'll share in the comments if I come up with anything.

Thanks for reading!

The Other Inconvenient Truth

While researching the environmental impacts of increased meat consumption, I came across an excellent TED Talk by Jonathan Foley titled The Other Inconvenient Truth. He describes the current state of the food system and identifies the need for future solutions so that we can feed 9 billion people by 2040. He covers some examples of the environmental impacts of  the modern agricultural system, including the drying of the Aral Sea and rainforest degradation in South America. His talk provides a really nice review of some of the information covered in Are Humans Becoming More Carnivorous? as well as a nice segue into some of the future topics that we'll be exploring here.

If you have twenty minutes to spare, you can check out his talk below.

If not, here's the short and compelling clip that Jonathan shows at the end of his talk.

Thanks for reading!