Agriculture and climate change
"It is too late for sustainable development. The best we can hope for is a sustainable retreat." James Lovelock, The Revenge of Gaia.
In this article, I equate agriculture with food production. In a wider sense, many of the points made here apply to other products of agriculture, as well as forestry, fishing and range management.
A brief history of agriculture
Agriculture is concerned with the provision of raw materials from the land. The root of the very word highlights the close link between cultivation of the soil and human civilisation. It first emerged 10-15,000 years ago in the tropical and subtropical regions of the earth, when populations became so dense that the wild harvest of the land was no longer enough to sustain people alone. The first crops were selected to produce nutrients that were hard to come by in the wild, i.e. carbohydrates. In parallel, the domestication of animals began to provide reliable sources of highly concentrated protein. From the beginning, agricultural techniques (primarily slash & burn, grazing, ploughing & range management of wild animals) put a pressure on the environment they were carried out in. In marginal areas, where water was scarce or excessively abundant, or where growing seasons were short, this led over time to local and regional soil degradation. We can see the results in areas as diverse as the British Uplands and Central Asia, both of which had their soils permanently degraded or irrevocably altered by early cultivation.
While for thousands of years rises in agricultural productivity and population were slow and cultivation went ahead with essentially the same techniques and tools, a qualitative change occurred over the last 300 or so years with the introduction of fossil fuels. This resulted in radical changes such as the beginning of long-distance trade in staples in the 18th Ct, the use of chemical fertilisers in the 19th, and the large-scale introduction of heavy machinery in the 20th century – not coincidentally after the end of World War II, when much of the arms industry was redirected to producing farming machinery. Over the same period, leaps in scientific knowledge enabled intensified breeding of high-yielding and stress-resistant crops, culminating in the “designer crops” of the GMO era. In parallel, systems such as biodynamics and permaculture have attempted to preserve traditional farming knowledge based on generations of observation & trial, or merge it with modern scientific knowledge & methods.
Impact of agriculture today
Agriculture contributes to climate change in a number of ways. The greatest contribution is through the degradation of soil by ploughing, which destroys the organic top layer of soil. This accounts for about the same amount of CO2 released into the atmosphere as the global fuel use of all motor vehicles. Intensively reared crops are removing significantly more nutrients from the soils than are being replenished either naturally or with fertilizer. About 85 percent of agricultural land contains areas degraded by erosion, salinisation, compaction, and other factors. Soil degradation has already reduced global agricultural productivity by 13 percent in the last 50 years. The use of Agricultural machinery, processing, storage and transport of food add to this tally.
In parallel with that, whole ecosystems are under threat or actively being destroyed by expanding agriculture. Agricultural conversion to croplands and managed pastures has affected a quarter of the global land area and displaced one-third of temperate and tropical forests and one-quarter of natural grasslands. Projections suggest that an additional one-third of the existing global land cover could be converted over the next 100 years.
Pollution from fertilisers and irrigation of croplands put additional stresses on these ecosystems, especially in dry lands. Irrigation diverts water from natural ecosystems and increases the salinity in irrigated areas, rendering them unproductive in the long run. The shrinking of the Aral sea in Central Asia (once the second largest inland body of water) by a third, and the drying up of the Colorado River are both a result of large-scale irrigation projects. Fertilizer and pesticide residues, along with animal waste, leach into waterways and degrade water quality. Agricultural runoff is already creating serious water pollution problems in the Mediterranean Sea, and the Gulf of Mexico. In terrestrial ecosystems, nitrogen saturation can disrupt soil chemistry, leading to loss of other soil nutrients and ultimately to a decline in fertility. Excess nitrogen can also wreak havoc with the structure of ecosystems, affecting the number and kind of species found. North America and Europe are suffering the most from the Nitrogen overload, but the developing world is catching up fast, with application rates of fertiliser rapidly increasing.
Our choice of food also affects the global climate. Intensively reared animals use up half of the cereal crops grown in developed countries, and a quarter of those in developing countries, while producing disproportionate amounts of methane, a greenhouse gas ten times as potent as carbon dioxide. Intensive meat production also uses about three times the amount of land compared to vegetables and grains, and three times as much fossil fuel. Industrial livestock farming systems account for three quarters of the world's poultry, two thirds of the egg production and nearly half of the pork supply. As well as putting small rural farmers out of business, a trend toward intensive animal production systems has serious implications for water, environmental and human health in both developed and developing countries. The huge amounts and high concentrations of animal waste are too much to deal with for the surrounding countryside. They also produce greenhouse gases in the form of methane and nitrous oxide, both far more potent than CO2.
The successive breeding of high-yielding crops and their exclusive selection for industrialised food production are threatening to undermine the genetic variety of crops, whose preservation is vital for survival in times of environmental stress, such as we are anticipating with accelerating changes in climate. Another threat is the creeping privatisation of the genetic pool via seed patenting and genetic manipulations by a handful of multinational companies, while at the same time farming populations and traditional land-based knowledge are in worldwide decline.
The demand for out of season and exotic produce increases food miles and diverts farmers in other countries from feeding themselves to providing luxury goods for people in the rich parts of the world. Per capita production of food is now higher in the developing world than in developed countries, yet hundreds of millions of people are still starving, as a direct result of distorted trade patterns and debt incurred by corrupt governments on behalf of their countries’ populations.
What if … - Climate change scenarios & impact on agriculture
There is little debate left now that average global temperatures will rise. The discussion is now by how much, and what will be the knock-on effects on regional climates. Rising sea levels will mean a loss of large areas of highly productive farmland in coastal and low-lying regions, where much of the most productive land lies. Climate and vegetation zones will be unstable for a few decades if not centuries, before a new equilibrium is reached. Rising temperatures will result in generally more arid conditions over much of the temperate regions, leading to a drop in agricultural productivity for conventional crops, and a decreased ability of the soil to store carbon. Desert and savannah will spread into areas currently intensively farmed, including in Central Europe and the Southern USA. Further shifts in regional climates and weather patterns may be affected by melting polar ice caps and melting permafrost in high Northern latitudes, and changes in ocean currents and wind patterns. The net effect of all these changes is a gradual and potentially drastic decrease in available productive land, both for human food production and the rest of the earth’s species and ecosystems.
Carrying capacity
How many people can the earth actually support, while also supporting the multitudes of other life forms and carrying out its life-sustaining functions? The answer depends partly on what limits we set ourselves, and on the physical limits of the planet for sustaining life. Previous estimates varied widely between 2.2 and 22 Billion, but most of them, especially the higher ones, gave little consideration to the earth as a self-sustaining system, which we only now begin to fully understand. This understanding leads to the conclusion that large parts of the land surface and oceans will need to be set aside & kept intact for so-called “ecosystem services”, i.e. cycling of carbon, nitrogen and other vital elements. This reduces the amount of land available to intensive food production.
In 1700, before Britain had begun to import large quantities of food from overseas (and before the Scottish highland clearances set in), the country could be assumed to be more or less self-sufficient in food & other raw materials. At this time, ca 5 Million people lived on the island. By 1851, the figure had risen to 20 Million, chemical fertilisers were slowly beginning to appear and global trade in food (such as wheat imports from Canada, replacing home-grown oats and barley) had begun. The current figure of over 6 Billion humans world wide, projected to peak at about 10 Billion around the year 2040, can safely be assumed to be unsustainable. The exponential rise of the world’s population between 1700 and now is directly linked with the rise in fossil fuel use over the same period. Together they exert a strain on the planetary life support system that is beginning to show ever more clearly.
The conclusion is that in order to ensure the survival of humanity, we have to take steps to reduce our numbers, the sooner the better. Even if we assume that the Earth can support two Billion people, we will soon outnumber this figure by a factor of five if current trends continue. A change from fossil-fuel intensive agriculture, which is necessary to avert catastrophic climate change, will result in at least a temporary drop in productivity. Add to this the potential loss of productive land to rising sea levels and expanding deserts, and it becomes clear that the future Earth will not be able to support as many people as the one that our grandparents inhabited.
To de-escalate the intensity and extent of human land use is a paramount ask of our and coming generations. To this end urgent action in the field of family planning is needed on a global scale, yet the subject is hardly present in the public consciousness, let alone in politics.
Tomorrow’s food
We know that we cannot feed ourselves in the future in the same way we have done until now. A number of alternatives are being pursued by different sectors of society, some with large amounts of public or private funding, and others by self-motivated, decentralised grassroots movements.
Food redistribution
A vital aspect of future food security is to re-establish local food production worldwide. Urban food production has high potential for intensive cropping, and precedents exist in the recent experiences of Cuba, as well as in history – cities such as Paris were net exporters of food in the late 19th century. A change in attitude to food production from a pursuit for peasants, servants or eccentrics towards an essential and universal human activity is necessary. This is a great educational task, while at the same time people need to gain access to land and resources for growing their own food. Local food production would include the recycling of organic waste including human faeces for food production. Under such circumstances, bioregional self-sufficiency may be achievable in many parts of the world, resulting in the drastic reduction in food miles in the developed world and the release of farmers of developing countries from producing cash crops for affluent Western consumers.
The low-tech path
Organic agriculture uses a fraction of the pesticides and fertilisers consumed by chemical agriculture & is therefore being less polluting, both in terms of greenhouse gasses and nutrient leaching. But it still relies on ploughing to a large extent, releasing soil carbon into the atmosphere. On the other hand, it tries to build up soil fertility & thereby soil carbon by adding manageable amounts of plant and animal-based fertilisers. In terms of efficiency, it is currently less productive than chemical agriculture, so more land will be needed to feed the same amount of people.
Permaculture is a design approach to providing food and other human needs using ecological principles, while preserving and restoring the Earth’s ecosystems. It maintains that the integration of food production and ecosystem services is possible. Soil preservation and restoration are key elements, achieved by use of perennial crops and no-till techniques of cultivation. Permaculture systems are less productive than intensive agriculture if purely output of food per area is measured. However, multiple yields are possible from the same area and ecosystem services can be combined with productive uses. A combination of organic cultivation and permaculture growing systems could potentially provide high and stable yields of diverse crops, while at the same time providing ecosystem functions such as soil creation and biodiversity havens. They are ideally suited for integration into human settlements on every scale, which would drastically reduce food miles. In the long run, they could also free up countryside for the preservation of existing ecosystems and the restoration of degraded ones.
Unfortunately, we have as yet very little experience with permanent growing systems, and many promising crops and their guilds have not been studied in detail for their productivity and long-term health. Much more intensive research and development of high-yielding perennial crops, their cultivation and processing is needed, as well as widespread education of farmers in their use and marketing. Considering the unpredictability of future regional climates, such research needs to “spread the bets” of what plants and animals will be best suited to future food production, as well as selecting species and varieties adapted to a wide range of conditions.
The high-tech path
While many of us may not like to see or even think about high-tech futures, we need to be aware that a great deal of public and private research money is spent on them, and consider if and how high-tech and low tech solutions could coexist in a future world.
These latter options would presume a continuing source of highly concentrated, readily available energy. With fossil fuel being unsuitable due to its implication in climate change, nuclear power would be the only existing alternative. In the short term, this would mean using nuclear fission, which is highly controversial. Storage of nuclear waste is an issue, as is the centralised control of the resources and the susceptibility to sabotage, terrorism and war. All of these would become increasingly likely in a world of diminishing and unevenly distributed resources. Nuclear fusion could theoretically provide an unlimited amount of energy with minimal resource use. Although there are recurring reports of progress with nuclear fusion, no definite breakthrough has been made yet, and it would be subject to the same risks as fission energy. The viability of this path depends on fast development of fusion energy, and (barring a nuclear dictatorship) a social consensus over the use of fission in the short and medium term, and how to deal with its waste products and associated risks.
The use of genetically modified organisms (GMO), proposed by scientists, business people and policy makers as a way to solve the future food crisis depends on high energy & technological input. Known risks include increased resistance of pests, the development of “superweeds” and the subsequent need for ever stronger doses of pesticides and herbicides. Other as yet unknown risks may become apparent, as research into these technologies and their side effects is in a very early stage. The ownership and access to GMOs is currently with a few exceptions kept exclusive to multinational corporations, although this does not necessarily need to be the case. As most currently developed GMOs are tied into the industrial mode of food production, they have limited use for achieving local food self-reliance.
Synthetic food production seems the stuff of science fiction, but in fat the production of edible foodstuffs using cultures & GMO, in artificial environments is already practiced. It may be able to provide food from a small amount of land with relatively low resource use, although it also depends on high inputs of energy. It is a technology still in its infancy, with more research and development required to reveal its true potential and any side effects and risks.
Conclusion
All the above strategies have the added disadvantage that they have been around for a relatively short time, and we haven’t got much experience regarding their viability, efficiency and possible side effects. As James Lovelock points out, lead-in times for new technologies and approaches are around 40 years from first public appearances to widespread acceptance. In the current conditions and with climate change a reality we haven’t got this much time. We will have to take risks, and also think about short and medium term strategies to feed the people of this earth while developing long-term sustainable methods appropriate to a number of people below the as yet unknown carrying capacity of the future Earth. This may mean uncomfortable decisions and often choosing only the least bad option, but the alternative would be a catastrophic descent with successive collapses in social structures and populations, desperate fights over dwindling resources and the rapid consumption of easily accessible natural resources including famine foods, undermining the survival base for all but a small number of humans on this planet.