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!

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!

Are Humans Becoming More Carnivorous? Environmental Impacts

In the previous post, we examined a new study by Bonhommeau et al. (2013) which revealed that global meat consumption has increased over the past five decades. How does an increase in meat consumption affect the environment?

Cows (photo from Living Green Magazine)

The livestock sector lies within the top two or three of the most important contributors to environmental issues, both locally and globally. Despite not being a major global economic player, the livestock sector is beneficial and crucial to society, employing and feeding growing global populations (Steinfeld et al., 2006; Herrero et al., 2009). Livestock agriculture contributes to environmental problems such as land degradation, land use change, climate change and greenhouse gas emissions, water shortage and pollution, nutrient excretion, loss of biodiversity, and competition for human food (Steinfeld et al., 2006; Janzen, 2011). These environmental impacts are driven by growing stresses on global human populations, namely the those of food, water, and energy security, biogeochemical interferences, and habitat (Janzen, 2011).

Let's now examine some of these impacts in a bit more detail. Many of the other impacts mentioned above will be the topics of future posts.

Land Use Change and Degradation

Land use refers to the ways in which land is used for human means. It is "characterised by the arrangements, activities and inputs that people undertake in a certain land cover type to produce change, or maintain it" (FAO, 2013). Land degradation refers to the reduction of resources as a result of processes which act on the land, including soil erosion, deterioration of the properties of the soil, and loss of natural vegetation (Steinfeld et al., 2006).

Deforestation for agriculture in Brazil's Pantanal wetland 
(from JNCC, 2013)

Livestock now represents the largest portion of human land use forms, affecting ecosystems around the world (Janzen, 2011). An example of environmental problems brought on by land use change for agriculture is the degradation of tropical rainforests, such as the Amazon. Two main phenomena are related to deforestation as a result of intensive raising of livestock, the first being the direct conversion of forest to pasture land and the second being the clearing of forest for crop growth to feed livestock (Herrero et al., 2009). Approximately 20-30% of the Earth's land surfaces are used for grazing, while approximately one third of cultivated land area is used to feed livestock (Janzen, 2011). 

GHG Emissions & Climate Change

Climate change is possibly the most pressing environmental challenge that has faced the planet. According to the IPCC (2013), the main authority on climate change, the "warming of the climate system is unequivocal, and since the 1950s, many of the observed changes are unprecedented over decades to millennia". This warming can be seen in the atmosphere, the ocean, the cryosphere, in sea level, and in carbon and biogeochemical cycles. The largest contributor to total radiative forcing is caused by the increases in anthropogenic GHGs, such as CO2, since 1750.

Disintegrating iceberg near West Greenland
(from The Guardian)

Animal agriculture produces GHG emissions in the form of CH4 from enteric fermentation, N2O from fertiliser use, CH4 and N2O from manure management practices, and CO2 from from fossil fuel and energy use (O'Mara, 2011) and land use and its changes (Herrero et al., 2009). Livestock induced emissions account for 2.4 billion tonnes of CO2 per year, and on a life cycle analysis basis, they contribute up to 18% of global GHG emissions (Steinfeld et al., 2006). 

Water Shortage and Pollution

Water is essential for life. Only 3% of the water on Earth is fresh, and surface water only accounts for 0.3% of the total amount of freshwater (this includes lakes, rivers, and streams). Another 68.7% of all freshwater is locked away in glaciers, while 30% of freshwater is located within the pores of the ground in the form of groundwater (US EPA, 2013). Approximately 64% of the world's population is expected to live in water-stressed basins by 2025 (Steinfeld et al., 2006).

Water shortage in China (photo from The Guardian)

Freshwater is extensively used in livestock agriculture, the most significant use coming from the irrigation of crops for intensive feeding operations. The livestock sector is a key player in increasing water use and represents 8% of global human water use (Steinfeld et al., 2006). For instance, approximately 16,000L of water are needed to produce 1kg of beef (Janzen, 2011). In terms of water pollution, the major sources from the livestock sector include animal waste, antibiotics and hormones, chemicals from tanneries, fertilisers and pesticides for feedcrops, and sediments from eroded pastures. These pollutants contribute to freshwater eutrophication, coastal dead zones, and the degradation of coral reefs, among others (Steinfeld et al., 2006).

As I mentioned above, these are only some of the many environmental impacts of livestock agriculture. Livestock's Long Shadow by Steinfeld et al. is currently the most comprehensive study on the environmental impacts of the livestock sector. I strongly recommend flipping through it if you're eager to learn more on the topic.

Having read about some of the environmental impacts arising from the livestock sector, what do you think are potential solutions for a more sustainable food industry? 

Thanks for reading!