It's all about soil

Today, it's all about soil and its role in helping us fight climate change. In my previous posts, I have addressed the misfortunes today's agricultural soil faces due to the use of fertilisers in modern farming. Before chemical fertilisers come into play, healthy soil is packed with microorganisms, retaining nutrients and moisture to grow plants. Healthy topsoil organic matter sucks up atmospheric nitrogen, converting it to ammonia and nitrates that is consumed by the plants. This biological cycle breaks down as soon as soil is treated with synthetic fertilisers, leading to topsoil loss and the release of carbon dioxide, a major greenhouse gas causing global climate change. So how do we stop this disastrous cycle?

Michael Pollan (author, journalist and professor of journalism at UC Berkeley Graduate School of Journalism) and Debbie Barker suggest that there is a way to make the soil work in favour of climate change mitigation.

(Source: https://www.washingtonpost.com)

But firstly, with the help of Pollan and Barker, let us take a closer look at what exactly has happened to our soil across the globe. Their article in the Washington Post explains: the industrialization of farming has allowed farmers to grow more crops more quickly. But modern techniques have also wreaked havoc on the earth, water and atmosphere. Intense plowing, for example, has introduced more oxygen into the soil, boosting the microbes that convert organic matter into carbon dioxide. The quest to wring every last dollar out of fields has put pressure on farmers to rely on chemical fertilisers. This often leaves fields more bare between growing seasons, allowing carbon to escape into the air. Scientists estimate that cultivated soil has lost 50 to 70 percent of its carbon, speeding up climate change.' Industrialised farming is also having a detrimental effect on water security, especially in places that are already experiencing acute water scarcity. The chemical treatment and extensive plowing of soil causes the ground to absorb water less efficiently. Any water that the soil cannot absorb becomes runoff, taking some of the chemicals and fertilisers with it to the nearest water body. This contaminates rivers, lakes and seas while putting human water supply sources at risk.

This all starts to sound very apocalyptic (as talking about climate change tends to do from time to time) but Pollan and Barker do suggest there is something we can do. It's called 'cover crops'. To all the farmers out there, try this! Cover crops (beans, rye and oats for example) are planted in between vegetable rows, keeping as much of the crop field covered and using up as much photosynthesis potential as possible. Cover crops also help to keep nitrogen and other nutrients in the soil, making it a favourable environment for the 'main crops' to grow without needing fertiliser treatment. Additionally, cover crops can be grown throughout the year to ensure the field never sits empty, leaving the soil exposed and wasting photosynthesis potential.

In reality, growing cover crops may be more difficult than it sounds. Pollan and Barker explain that current federal policy in the United States ensures that farmers do not waste their time growing crops they cannot sell, limiting growing season for cover crops. In order to allow carbon friendly farming, these policies need a revisit.

(Source: https://broadforkfarm.files.wordpress.com)

In addition to the cover crop strategy, a switch towards organic fertilisers instead of synthetic nitrogen ones should be encouraged. Research at UC Berkeley shows that 'applying a single layer of compost, less than an inch thick, to rangelands stimulates a burst of microbial and plant growth that sequesters dramatic amounts of carbon in the soil - more than 1.5 tons per acre.' All these practices fit into a lifecycle of a sustainable, organic and self-sustaining farm. Cattle are used to graze the fields, cattle manure is used to fertilise the crops and fields, plant growth increases due to manure fertilisation and the process starts again. In the meantime, cattle are fed with organic grass rather than corn, leaving out the industrialised, fossil-fuel intensive corn production from the equation. Sounds too good to be true?

Unfortunately, it probably is, for the moment. At a global level at least. As world leaders gather in Paris over the next week to address the global action plan on climate change, food production and food related climate change does not seem to be on the list of priorities. Transport and energy sectors will likely to take the front seat at the conference. However, I do hope that when the next climate change conference comes along, agriculture induced climate change will have a central seat at the table. In the mean time, change will have to come from local and government level. It seems to me that changes that can be done in the agriculture sector to slow down climate change are just too good to miss out on. But hey, that's just me.

Until next time,

Laura

The Wasteful Epidemic

Think about the last time you went shopping for food. Did you end up consuming all of what you bought? If yes, then congratulations! Most of us however end up throwing away large amounts of what we buy. In fact, about one third of the food that is produced in the world for human consumption is wasted through various steps of the supply chain (Gustavsson et al, 2011). I have already argued in my previous posts that global food production is extensively fossil fuel intensive and a burden for the environment. If we take into account all the damage food production does to our planet, it is alarming to think that one third of that is for nothing! 

So where does all this waste go? One third of the world food production- that is about 1.3 billion tonnes! Every year, developed countries throw away almost as much food (222 million tonnes) that is equivalent to total food production in the whole of Sub-Saharan Africa (230 million tonnes) (UNEP, 2009). All this wasted food ends up most commonly in landfills, which are one of the largest sources of methane, a dangerous greenhouse gas. Combining the environmental damage occurred during the production of food waste with the emissions released during the disposal of it, we have ourselves a dangerous and destructive cycle of food waste.

(Source: http://www.consumercheckpoint.co.uk)

On a more scientific note, Grizetti et al (2013) just recently published a study that looks at how food waste contributes to nitrogen pollution. The authors took to account the nitrogen pollution that is released into air, water and soil and found out that 'food waste represents about 12% of the total nitrogen loss to the environment due to food production, with meat being responsible for about 50% of the emissions' (Grizetti et al, 2013). They also point out that 35% of the nitrogen emissions are pumped into the atmosphere and 65% into the planet's water systems. The threat to water systems due to nitrogen comes in the form of water eutrophication (caused mainly by nitrate)- the over-enrichment of water systems by nutrients. This can undermine water quality, reduce oxygen supply in the water system and cause biodiversity loss. In the EU, food and drink consumption is responsible for more than 50% of eutrophication. In fact red meat has the highest destructive eutrophication potential.

How water eutrophication looks like (water 'blooming') 

(Source: http://www.wri.org)

As the authors mainly focus on measuring the nitrogen pollution that results from food waste, they do offer a few suggestions for future action. It is suggested that in order to cut down on global food waste, better management within the food supply chain is essential. Steps of the supply chain like distribution, retailing and processing see large amounts of food being wasted before it even reaches the shelves of the supermarkets. This could be decreased by operating a short supply chain (locally produced) as transporting food adds on to the food waste figures. For example, a Dutch french fries producer admitted the need to throw away many of its potatoes even before production due to damages occurred during loading and transportation (Gustavsson et al, 2011). The other obvious way of reducing food waste is by changing people's habits. A recent attempt to change consumer behavior is the Love Food Hate Waste campaign that was launched in 2007, now operating all over the UK. It is a campaign to raise public awareness towards domestic food waste and to help people make most of their food. They give tips for appropriate storage, portion planning and recipes. Thanks to the campaign, food waste is now a topical issue in the media and considered as a real problem (Tesco's food waste in the news).

(Source: http://www.recycleforgreatermanchester.com)

In order to cut down on food waste, effort from consumers and suppliers is essential. Changing people's habits developed by consumerism can be a difficult task but as seen with Love Food Hate Waste, more attention is going towards the issue. But can you already see the links between other problems with the food sector: food waste, meat consumption and food trade? This is a topic that I will return to in future posts. For now, I leave you with a TED talk by Tristram Stuart who presents shocking data about the global food waste scandal and calls for a more responsible use of the planet's resources. Hope you enjoy it!

Till next time,

Laura

Warning: Agricultural Chemicals!

In order to grow our food faster, cheaper and bigger, modern agriculture has opted to a wide variety of chemical pesticides and inorganic fertilisers. Fertilisers in the form of manure and compost have been used for centuries but the use of chemical fertilisers only relates to the industrial Green Revolution in the 20th century. Fertilisers, especially nitrogen based, have seen a dramatic tenfold increase since 1950s (Robertson and Vitousek, 2009). But due to the fact that we are unable to keep nitrogen from leaving cropped ecosystems though various pathways (mainly waterways and atmosphere), fertiliser use brings well-documented and significant environmental impacts. Nitrogen is a central element in living systems but overuse and mismanagement have severe consequences (Robertson and Vitousek, 2009).

One of the first synthetic pesticides, dichlorodiphenyltrichloroethane (DDT), was widely used during World War II to kill malaria-bearing mosquitos and typhus-carrying lice. After the war, it became a popular pesticide to kill off unwanted pests on farms. In 1972, DDT was banned in the United States as the Environmental Protection Agency (EPA) noticed an adverse affect on wildlife as well as humans. Today, due to its persistence in the environment, DDT is considered as a human carcinogen and is still in use in some parts of the world. This proves how little we know about the effects of chemical fertilisers on humans but also the environment.

Modern agricultural industry takes advantage of many synthetic fertilisers pushing up yields and helping to feed the planet's growing population. But at what price? The use of synthetic fertilisers causes a systematic change in the way we think about soil and organic matter. Before chemical fertilisers, healthy soil was packed with microorganisms, retaining nutrients and moisture to grow plants. In addition, topsoil organic matter sucked up atmospheric nitrogen, converting it to ammonia and nitrates that was consumed by the plants. This biological cycle breaks down as soon as soil is treated with synthetic fertilisers, leading to topsoil loss and the release of carbon dioxide, a major greenhouse gas causing global climate change.

Nitrogen is used in nearly all synthetic fertilisers as it acts as an important nutrient for plants. When nitrogen fertilisers are used on soils, the chemical processes following cause the fertiliser to break down and the releasing of nitrous oxide. In fact, synthetic fertilisers are to blame for more than 75% of all agricultural nitrous oxide emissions (EPA, 2012). But what is so special about nitrous oxide?

Global Greenhouse Gas Emissions by Gas

Source: IPCC, 2007

To answer that, we need to look more specifically how effective nitrous oxide is in trapping heat. If we compare carbon dioxide to nitrous oxide, the latter is 296 times more powerful in trapping heat, leaving us more than worried. While carbon dioxide takes the biggest piece of the pie for greenhouse gas emissions (IPCC, 2007), it may not be the most dangerous one in terms of climate change potential.

But what about the production of fertilisers? It turns out, the modern agriculture industry has transformed soil fertility into a fossil fuel intensive 'business'. Consider this: in order to produce a ton of fertiliser, more than 930 litres of natural gas. Furthermore, raw materials for the fertilisers often have to be mined or manufactured away from production sites, adding the transportation cost in terms of emissions. Not to mention how half of the nitrogen fertiliser applied on crops in the United States is leaching through to the soil and the waterways. This makes fertiliser use wasteful, harmful for the environment and dangerous for humans.

Promotion of fertilisers in 1942 by the Tennessee Valley Authority- right-hand side field was treated with phosphate and lime, the left-hand side was not treated.

It is important to realise another dramatic consequence of excessive nitrogen release into the environment: hypoxia. This phenomenon occurs when nitrogen gets released into waterways and 'high nutrient levels stimulate algal growth, and when algae sink into deeper water and die, their sub- sequent decomposition by bacteria consumes dissolved oxygen deep in the water column faster than it can be replenished from the sur- face, leading to the development of hypoxia and the reduction or elimination of deeper-water organisms that require oxygen' Robertson and Vitousek, 2009:103). This process dramatically disturbes the natural habitat of biodiversity and leads to the unbalancing of natural nitrogen cycles. 

 

Looking through the evidence that I have gathered here, it is clear that both humans and the environment have taken a hit due to the introduction of the synthetic fertilisers and chemical pesticides. In order to reduce the human health hazards, reduce the impacts on climate change and to make way for more sustainable farming, the focus should lie on organic fertilisers, which preserve the soil's organic matter. With modern technology advancements and our knowledge of past mistakes, there is hope that such fertilisers will come to dominate the future food production.



Till next time,
Laura

The Dirty Food Sector- A Brief Overview

This time I want to take a look at how our food industry has made its way into the workings of the economy and how its hidden costs are are fueling climate change. Looking at the breakdown of emissions by sector, it seems like the agricultural sector takes up a relatively modest 13.5% of global carbon dioxide emissions, while energy supply contributes with 25.9% and industry with 19.4% (IPCC, 2007).

Carbon dioxide emissions by sector

Source: IPCC 2007, 'Synthesis Report'

But do these figures really show us the truth about agriculture? It is easy to assume, looking at the data, that food production is one of the least problematic sectors causing carbon dioxide emissions (the most important anthropogenic green house gas). However, it is important to realise that modern food production is fueling climate change from virtually every sector of the world's economy. It is estimated that in reality, food related emissions make up about one third of total greenhouse gases heating our planet (Vermeulen et al, 2012). Food is everywhere!

To illustrate how our food system is accountable for all these emissions, let's look at food trade.  The global food trade has increased more than tenfold in the past 60 years (Schmitz et al, 2012). Using fossil fuel based transport solutions, food trade is a major polluter hiding behind the transport sector. With the excuse of increasing consumer choice, food is being transported from one corner of the world to another, every day. As a disturbing example, in 2008, the US exported 1.9 billion pounds and imported 2.5 billion pounds of beef and veal. Can we really taste the difference? Looking at these figures, one can only imagine how much energy and refrigerating these carcases require to get around the world. I will dedicate a separate post to talk about global food trade later in the course of the blog.

In addition to trade, production of chemical pesticides and fertilisers are energy-intensive and rich in terms of emissions that they emit. Moreover, production and usage of these chemicals releases other anthropogenic gases more dangerous than carbon dioxide. All of these issues will be discussed in greater detail in following posts. New technological and chemical discoveries are to thank for the birth of industrialised food. Modern food industry exploits fossil fuels in order to produce cheaper, faster and in bigger quantities, to ship food all over the planet and to process it for a greater profit. Never has food production been in the hands of so few producers. But at what price?

Garnett (2011) points out that our whole food chain emits greenhouse gases- starting from the farm and finishing on our plates, but the largest polluter is the agricultural stage. The graph below shows 40% of greenhouse emissions relating to the food sector come from the agriculture stage, making it the most promising opportunity to reduce food chain emissions. Although food chain greenhouse emissions are a major environmental issue, we have to remember that our food industry also puts a threat on biodiversity, water use, animal welfare and human nutrition. In the course of the next few months, I want to touch upon all of these but the main focus will be on greenhouse emissions.

Food chain greenhouse emissions by sector.

Source: Garnett (2011)

I hope this post gives a brief overview of what we are dealing with when talking about modern food industry. Problems like food trade, pesticides, fertilisers and processing will be featured in future posts. Until then, here is another short and light TED talk (apologies for my obsession with TED talks) by an 11-year-old Birke Baehr who explains what is wrong with our food system. He emphasises on the aspect of human health and the role of genetically modified food. This is the story seen through a kid's eyes. Enjoy!

Till next time,
Laura