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Tuesday, April 27, 2010 @ 05:04 AM
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GLOBAL WARMING

THE COMPLETE BRIEFING

JOHN HOUGHTON

Co-Chairman of the Scientific Assessment Working Group of the Intergovernmental Panel on Climate Change

CAMBRIDGE UNIVERSITY PRESS            REPRINTED 1999

PART II

Chapter 4: Climates of the Past (continued)

The past million years

  • Deep cores have been drilled out of the ice at several locations in both Greenland and Antarctica. The longest and most recent core reached a depth of over 2.5 km. The ice at the bottom fell as snow over 200,000 years ago.
  • Small bubbles of air are trapped within the ice. Analysis of the composition of that air shows what was present in the atmosphere for the time at which the ice was formed – gases such as carbon dioxide or methane.
  • A temperature record for the polar regions can therefore be constructed from analyses of the ice cores.
  • Reconstruction from a Vostok core shows that the last major ice age began about 120,000 years ago and ended about 20,000 years ago. It also demonstrates the close connections which exist between temperature and carbon dioxide and methane concentrations.
  • To go further back, over the past million years, the composition of ocean sediments can be investigated to yield information. From oxygen isotope and other data we can deduce that the sea level at the last glacial maximum, 20,000 years ago, was about 120m lower than today.
  • Over the last million years six or seven major ice ages can be identified with warmer periods in between, the period between these major ice ages being approximately 100,000 years. Other cycles are also evident in the record.
  • So far as is known the output of the sun has not changed to any significant extent over the last million years or so. But because of variations in the Earth’s orbit, the distribution of solar radiation has varied in a more or less regular way during the last millennium.
  • Three regular variations occur in the orbit of the Earth around the sun. Although nearly circular, the Earth’s orbit is actually an ellipse. The eccentricity of the ellipse varies with a period of about 100,000 years; that is the slowest of the three variations.
  • The Earth also spins on its own axis, the axis of spin being tilted with respect to the axis of the Earth’s orbit, the angle of tilt varying between 21.6° and 24.5° (currently it is 23.5°) with a period of about 41,000 years.
  • The third variation is of the time of the year when the earth is closest to the sun with a period of about 23,000 years.
  • Although the total quantity of solar radiation reaching the Earth varies very little, the distribution of that radiation with latitude and season over the Earth’s surface changes considerably, being especially large in the polar regions.
  • In 1867 James Croll pointed out that the major ice ages of the past might be linked with these regular variations in the seasonal distribution of radiation reaching the earth.
  • Milankovitch showed, from inspection by eye, a significant connection between the variations of polar summer sunshine and global ice volume. Careful study of the correlation of the two curves provides support for the Milankovitch theory.
  • More careful study of the relationship between the ice ages and the Earth’s orbital variations shows that the size of the climate changes is larger than might be expected from forcing by the radiation changes alone. Positive feedback processes have to be introduced to explain the climate variations.
  • As we shall see in later chapters, climates of the past cannot be modelled successfully without taking into account the influence on climate of variation in carbon dioxide concentration.

How stable has past climate been?

  • The growth and recession of the large polar ice-sheets between the ice ages and the intervening warmer interglacial periods have taken on average many thousands of years.
  • Over the last 8,000 years or so, which can be investigated more thoroughly than earlier epochs, the climate has shown some slow changes but no dramatic fluctuations. There is substantial evidence that the last 8,000 years have been unusually stable.
  • In 1993, Professor Dansgaard found evidence that rapid variations of the Arctic temperature frequently occurred during the glacial period up to 100,000 years ago.
  • These variations have been up to five or six degrees Celsius and have sometimes occurred over periods of less than a hundred years.
  • For 6,000 years before the start of the Younger Dryas event the earth had been warming up after the end of the last ice age. But then the climate swung back again into much colder conditions similar to those at the end of the last ice age.
  • At the end of the event, 10,700 years ago, the warming in the Arctic of about 7°C occurred over only about 50 years and was associated with decreased storminess and an increase of precipitation of about 50%.
  • Two main possible reasons have been suggested: major breakups of ice-sheets occurred releasing massive numbers of icebergs into the north Atlantic; and that the ocean circulation in the north Atlantic region has been strongly affected by injections of fresh water from the melting ice.
  • At present the ocean circulation here is strongly influenced by cold salty water sinking to deep ocean levels because its saltiness makes it dense; this sinking process is part of the ‘conveyor belt’ which is the major feature of the circulation of deep ocean water around the world.
  • Large quantities of fresh water from the melting of ice would make the water less salty, preventing it from sinking and thereby altering the whole Atlantic circulation.
  • This link between the melting of ice and the ocean circulation is a key feature of the explanation put forward by Professor Wallace Broecker for the Younger Dryas event.
  • As the great ice-sheet over North America began to melt at the end of the last ice age, the melt water at first drained through the Mississippi into the Gulf of Mexico.
  • Eventually, however, the retreat of the ice opened up a channel for the water in the region of the St Lawrence river. This influx of fresh water into the north Atlantic reduced its saltiness, thus, Broecker postulates, cutting off the formation of deep water and that part of the ocean ‘conveyor belt’.
  • Warm water was therefore prevented from flowing northward, resulting in a reversal to much colder conditions. The suggestion is also that a reversal of this process with the starting up of the Atlantic ‘conveyor belt’ could lead to a sudden onset of warmer conditions.
  • Our perspective regarding the possibilities of future climate change needs to take into account the rapid climate changes which have occurred in the past.
  • I move on in the next chapter to describe how, through computer models of the climate, predictions can be made about what climate change can be expected in the future.

Chapter 5: Modelling the Climate

Chapter 2 looked at the greenhouse effect in terms of a simple radiation balance. That gave an estimate of the rise in the average temperature at the surface of the Earth as greenhouse gases increase. But any change in climate will not be distributed uniformly everywhere; the climate system is much more complicated than that. More detail in climate change prediction requires very much more elaborate calculations using computers. The problem is so vast that the fastest and largest computers available are needed. But before computers can be set to work on the calculation, a model of the climate must be set up for them to use. A model of the weather as used for weather forecasting will be used to explain what is meant by a numerical model on a computer, followed by a description of the increase in elaboration required to include all parts of the climate system in the model.

Chapter 6: Climate Change under Business-as-usual

The last chapter showed that the most effective tool we possess for the prediction of future climate change due to human activities is the climate model. This chapter will describe the predictions of models for likely climate change next century. It will also consider other factors which might lead to climate change and assess their importance relative to the effect of greenhouse gases.

To summarize this chapter:

  • The increase in greenhouse gases is by far the largest of the factors which can lead to climate change during the next century.
  • The likely climate change for a business-as-usual scenario of greenhouse gas emissions has been described in terms of global average temperature and in terms of regional change of temperature and precipitation and the occurrence of extremes.
  • The rate of change is likely to be larger than the Earth has seen at any time during the past 10,000 years.
  • The changes which are likely to have the greatest impact will be changes in the frequencies, intensities and locations of climate extremes, especially droughts and floods.
  • Sufficient fossil fuel reserves are available to provide for continuing growth in fossil fuel emissions of carbon dioxide well into the twenty-second century. If this occurred the climate change could be very large indeed and have unpredictable features or ‘surprises’.

The next chapter will look at the impact of such changes on sea level, on water, on food supplies and on human health. Later chapters of the book will then suggest what action might be taken to slow down and eventually to terminate the rate of change.

Chapter 7: The Impacts of Climate Change

The last two chapters have detailed the climate change which we can expect next century because of human activities in terms of temperature and rainfall. To be useful to human communities, these details need to be turned into descriptions of the impact of climate change on human resources and activities. The questions to which we want answers are: how much sea level rise and what effect will that have?; how much will water resources be affected?; what will be the impact on agriculture and food supply?; will natural ecosystems suffer damage and how will human health be affected? This chapter considers these questions.

How much will sea level rise?

  • There is plenty of evidence for large changes in sea level during the Earth’s past history.
  • Various contributions to the likely sea-level rise next century are shown in fig. 7.1. The largest comes from thermal expansion of water in the oceans. The other main contribution comes from the melting of glaciers.
  • Estimates for the average sea-level rise under the business-as-usual scenario is 12 cm by 2030 and 50 cm by 2100. Sea-level rise will not be uniform over the globe.

The impacts of sea-level rise

  • Half of humanity inhabits the coastal zones around the world. Within these, the lowest lying are some of the most fertile and densely populated. To people living in these areas, even a fraction of a metre increase in sea level can add enormously to their problems.
  • Some of the areas which are especially vulnerable are Bangladesh and similar delta areas, the Netherlands and the small low-lying islands in the Pacific and other oceans.
  • It is quite impractical to consider full protection of the long and complicated coastline of Bangladesh from sea-level rise. Substantial amounts of good agricultural land will be lost.
  • Half the country’s economy comes from agriculture. 85% of the nation’s population depends on agriculture for its livelihood. Many of these people are at the very edge of subsistence.
  • Bangladesh is extremely prone to storm surges. Every year, on average, at least one major cyclone attacks Bangladesh. The storm surge in 1970 claimed the lives of over a quarter of a million people.
  • At the present time, it is estimated that saltwater intrusion extends seasonally inland over 150 km. With a one metre rise in sea level, the area affected could double, with a large effect on fresh water.
  • A similar situation exists in the Nile delta of Egypt. Many other examples of vulnerable delta regions can be given.

The impact on fresh water resources

  • The global water cycle is a fundamental component of the climate system. Water is also a key substance for humankind; to drink, for the production of food, for health and hygiene, for industry and transport.
  • Water use averaged per capita varies from 1,000 cubic metres (220,000 imperial gallons) per year to over 50,000 cubic metres (11 million imperial gallons).
  • Those in very poor areas may walk many hours each day to fetch a few gallons.
  • The demands of increased populations and the desire for higher standards of living have brought with them much greater requirements for fresh water.
  • Two-thirds of human water use is for agriculture, much of it for irrigation; about a quarter is used by industry and 10% is used domestically. Non-replaceable ancient water is being tapped for current use.
  • With this rapid growth of demand comes greatly increased vulnerability regarding water supplies.
  • Many of the world’s major sources of water are shared. The Danube passes through 12 countries, the Nile through 9, the Ganges-Bramaputra through 5.
  • The availability of fresh water will be substantially changed in a world affected by global warming. The increase in temperature means higher evaporation, when some parts of the world will have less rainfall, especially in summer, resulting in less run-off.
  • Other parts of the world will have increased precipitation. During the period 1980-85, more than 160 major floods were recorded.
  • The effects of droughts tend to be felt over a long period of time. Droughts and floods are likely to occur in locations where, at present, such disasters are rare. Extensive deforestation can lead to large changes in rainfall.
  • Irrigation is applied to one-sixth of the world’s farmland which produces about one-third of the world’s crops. Microirrigation techniques provide large opportunities for water conservation. Management of existing infrastructure can be improved.

Impact on agriculture and food supply

  • Every farmer understands the need to grow crops or rear animals suited to the local climate.
  • Between the mid-1960s and the mid 1980s global food production rose by an average annual rate of 2.4% – faster than global population. Grain production grew at an annual rate of 2.9%.
  • Two of the primary crops grown in Peru are very sensitive to the amount and timing of rainfall and are strongly affected by El Niňo events. Improved weather forecasting and planning by farmers has resulted in improved food production following El Niňo events.
  • Production in developed countries with relatively stable populations may well increase, whereas that in many developing countries (where large population increases are occurring)  is likely to decline as a result of climate change.
  • The disparity between nations will tend to become larger, as will the number of those at risk from hunger.
  • Firstly, there is large need for technical advances in agriculture in developing countries requiring investment and widespread local training. Secondly, improvements need to be made in the availability and management of water for irrigation, especially in arid or semi-arid areas of the world.
  • There is yet no strong evidence that the effect of climate change on global food supply is likely to be large. What needs urgent research is how well world agriculture will respond to extremes, such as prolonged droughts.
  • The surplus of food in developed countries is likely to increase, while developing countries will face large population increases coupled with a likely relative decrease in food production. Such a situation will raise enormous problems and serious deprivation especially in the developing world.
  • Agriculture is the main source of employment in developing countries. People will tend to migrate to places where they might be employed in agriculture. With pressures of rising populations such movement is likely to be increasingly difficult and we can expect large numbers of environmental refugees.

The impact on natural ecosystems

  • A little over 10% of the world’s land area is under cultivation. The rest is unmanaged by humans. Of this about 30% is natural forest.
  • Changes in climate alter the suitability of a region for different species. In the past these changes took place over thousands of years. With global warming similar changes occur over a few decades. Most ecosystems cannot respond or migrate that fast.

The impact on human health

  • Many of the factors that lead to a deteriorated environment also lead to poor health. Pollution of the atmosphere, polluted or inadequate water supplies, and poor soil (leading to poor crops and inadequate nutrition) all present dangers to human health and wellbeing and assist the spread of disease.
  • The main direct effect of climate change on humans will be that of heat stress in the extreme high temperatures that will become more frequent and more widespread.
  • A further likely impact of climate change on health is the increased spread of diseases in a warmer world. The potential impact of climate change on human health could be large.

Chapter 8: Why should we be concerned?

I have been describing the likely changes in climate which may occur as a result of human activities, and the impact these may have in different parts of the world. But large and potentially devastating changes are likely to be a generation or more away. So why should we be concerned? What responsibility, if any, do we have for the planet as a whole and the great variety of other forms of life which inhabit it? And does our scientific knowledge in any way match up with other insights, for instance ethical and religious ones, regarding our relationship with our environment? In this chapter I want to digress from the detailed consideration of global warming (to which I shall return) in order to briefly explore these fundamental questions and to present something of my personal viewpoint on them.

Chapter 9: Weighing the Uncertainty

This book is intended to present clearly the current scientific position on global warming. A key part of this presentation must concern the uncertainty associated with all parts of the scientific description, especially with the prediction of future climate change, which forms an essential consideration when decisions regarding action are being undertaken. However, uncertainty is a relative term; utter certainty is not often demanded on everyday matters as a prerequisite for action. Here the issues are complex; we need to consider how uncertainty is weighed against the cost of possible action.

Chapter 10: A Strategy for Action to Slow and Stabilize Climate Change

Following the awareness of the problems of climate change aroused by the IPCC scientific assessments, the necessity of international action has been recognized. In this chapter I address the forms that action could take.

Chapter 11: Energy and Transport for the Future

We flick a switch and energy flows. Energy is provided so easily for the developed world that thought is rarely given to where it comes from, whether it will ever run out or whether it is harming the environment. Energy is also cheap enough that little serious attention is given to conserving it. However, most of the world’s energy comes from the burning of fossil fuels which generates a large proportion of the greenhouse gas emissions into the atmosphere. If these emissions are to be reduced, a large proportion of the reduction will have to occur in the energy sector. There is need, therefore, to concentrate the minds of policymakers and indeed of everyone on our energy requirements and usage. This chapter looks at how future energy might be provided in a sustainable manner.

Chapter 12: The Global Village

The preceding chapters have considered the various strands of the global warming story and the action that should be taken. In this last chapter I want first to present some of the challenges of global warming, especially those which arise because of its global nature. I then want to put global warming in the context of other major global problems faced by humankind.

Tuesday, April 27, 2010 @ 05:04 AM
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2010 Diary week 17

Global warming, climate change and weather extremes

Book Review

Last week the first part of Global Warming: The Complete Briefing was reviewed. This week Part II points out that “As the great ice-sheet over North America began to melt at the end of the last ice age, the melt water at first drained through the Mississippi into the Gulf of Mexico.” “The retreat of the ice opened up a channel for the water in the region of the St Lawrence river. This influx of fresh water into the north Atlantic reduced its saltiness, thus, cutting off that part of the ocean ‘conveyor belt’.” “Warm water was prevented from flowing northward, resulting in a reversal to much colder conditions.” “The increase in greenhouse gases is by far the largest of the factors which can lead to climate change during the next century.” “The rate of climate change is likely to be larger than the Earth has seen at any time during the past 10,000 years.” “Estimates for the average sea-level rise under the business-as-usual scenario is 12 cm by 2030 and 50 cm by 2100.” “Half of humanity inhabits the coastal zones around the world. Within these, the lowest lying are some of the most fertile and densely populated. To people living in these areas, even a fraction of a metre increase in sea level can add enormously to their problems.”

Monday, April 26, 2010 @ 10:04 AM
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Honeysuckle Arch entrance to Davids Garden

Incredible poppy display in front of house

Lots of fresh salad to eat!

Enjoy the peace and tranquility of life in Lakkia.  We feel so blessed to be stewards of this land and to be able to share the bounty with our family and friends.

Tuesday, April 20, 2010 @ 09:04 PM
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GLOBAL WARMING

THE COMPLETE BRIEFING

JOHN HOUGHTON

Co-Chairman of the Scientific Assessment Working Group of the Intergovernmental Panel on Climate Change

CAMBRIDGE UNIVERSITY PRESS            REPRINTED 1999

PART I

Introduction to the First Edition

  • It is only during the last thirty years or so that human activities have been of such a kind or on a sufficiently large scale that their effects can be significant globally. Because the problems are global, all nations have to be involved in their solution.
  • The intergovernmental body which has been set up to assess the problem of global warming is the Intergovernmental Panel on Climate Change (IPCC), formed in 1988.
  • Their first scientific report was published at the end of May 1990. Much of the continuing assessment of climate change has been focused on the IPCC and its three working groups dealing respectively with science, impacts and response strategies.

Introduction to the Second Edition by John Houghton, 1997

  • Since the publication of the first edition nearly three years ago, interest in the issue of Global Warming and concern about it has continued to grow. This revised edition takes into account the further information from the 1995 IPCC reports.
  • Some of my colleagues sometimes comment on how formidable is the task of stewardship of the Earth feeling that it is perhaps beyond the capability of the human race to tackle it adequately.
  • I feel optimistic for three main reasons: I have seen how the world’s scientists have worked closely and responsibly to provide a consensus; the technologies required to provide greater efficiency in the use of fossil fuels and for their replacement with renewable sources of energy are available and affordable; my belief in God’s commitment to the material world coupled with his offer of partnership in caring for it, makes stewardship of the Earth an especially exciting and challenging activity.

Chapter 1: Global Warming and Climate Change

  • Many new things have happened in the last seventy years that could not have been predicted in the 1920s. The pace of change is such that even more novelty can be expected in the next seventy.
  • The last million years have seen a succession of major ice ages interspersed with warmer periods. The last of these ice ages began to come to an end about 20,000 years ago and we are now in what is called an interglacial period.
  • The climate of a region is its average weather over a period of a few months, a season or a few years. Most of the worst disasters in the world are weather- or climate-related.

The 1980s: a remarkable decade

  • The 1980s were unusually warm. Globally speaking, the decade has been the warmest since accurate records began over one hundred years ago and unusually warm years have continued into the 1990s.
  • 1995 was the warmest on record and eight of the nine warmest years in the record occurred in the 1980s and early 1990s.
  • The period has been remarkable for the frequency and intensity of extremes of weather and climate. About eighty hurricanes and typhoons occur around the tropical oceans each year.
  • Low-lying areas such as Bangladesh are particularly vulnerable to the storm surges associated with tropical cyclones.
  • Because of the likely locations of floods and droughts, they often bear most heavily on the most vulnerable in the world, who can have little resilience to major disasters.

The El Niňo event

  • Rainfall patterns which lead to floods and droughts in tropical and semi-tropical areas are strongly influenced by the surface temperature of the oceans. About every three to five years a large area of warmer water appears and persists for a year or more, known as the El Niňo.
  • A particularly intense El Niňo occurred in 1982-83 when surface temperatures were 7 °C above the average causing droughts and floods in almost all the continents.

The effect of volcanic eruptions on temperature extremes

  • Volcanoes inject enormous quantities of dust and gases into the upper atmosphere.
  • One of the largest volcanic eruptions this century was that from Mount Pinatubo in the Philippines on 12 June 1991 which injected about 20 million tonnes of sulphur dioxide into the stratosphere together with enormous amounts of dust.
  • The amount of radiation from the sun reaching the lower atmosphere fell by about 2% and global average temperatures fell by about a quarter of a degree Celcius for two years.

Vulnerable to change

  • Any large change to the average climate tends to bring stress to human communities. Changes in climate which indicate a genuine long-term trend can only be identified after many years.
  • Because of human activities especially the burning of fossil fuels, carbon dioxide in the atmosphere has been increasing over the past two hundred years and more substantially over the past fifty years.
  • The generally cold period worldwide during the 1960s and early 1970s caused speculation that the world was heading for an ice age, but the cold trend soon came to an end.
  • Later chapters will look in detail at the science of global warming and at the climate changes that we can expect, as well as investigating how these changes fit in with the recent climate record. Here, however, is a brief outline of current scientific thinking on the problem.

The problem of global warming

  • Human industry and other activities such as deforestation are emitting increasing quantities of gases, in particular the gas carbon dioxide, into the atmosphere.
  • Every year these emissions add a further 7,000 million tonnes, much of which is likely to remain there for a period of a hundred years or more.
  • Increased carbon dioxide acts like a blanket over the surface, keeping it warmer than it would be otherwise. With the increased temperature the amount of water vapour in the atmosphere also increases, providing more of a blanket effect and causing it to be even warmer.
  • An increase in global temperature will lead to global climate change. With the rapid change taking place in the world’s industry the change is unlikely to be either small or slow.
  • In the absence of efforts to curb the rise in the emissions of carbon dioxide, I estimate that the global average temperature will rise by a quarter of a degree Celcius every ten years – faster than the global average temperature has changed at any time over the past ten thousand years.
  • As there is a difference in global average temperature of only about five or six degrees between the coldest part of an ice age and the warm period in between ice ages, we can see that a few degrees in this global average can represent a big change in climate.
  • Substantial uncertainty remains about just how large the warming will be and which regions will be most affected and in what way.

Uncertainty and response

  • Until predictions improve to the point where they can be used as a clear guide to action, politicians and others making decisions are faced with the need to weigh scientific uncertainty against the cost of the various actions which could be taken in response to the threat of climate change.
  • Some actions can be taken at little cost (or even at a net saving) such as programmes to conserve and save energy, reducing deforestation and planting trees. A large shift to renewable energy sources will take some time, but a start can be made.
  • In the following chapters I shall first explain the science of global warming, the evidence for it and the current state of the art regarding climate prediction. I shall then go on to say what is known about the likely impacts of climate change on human life – on water and food supplies for instance.
  • The questions of why we should be concerned for the environment and what action should be taken in the face of scientific uncertainty is followed by consideration of the technical possibilities for the large reductions in the emissions of carbon dioxide and how these might affect our energy sources and usage, including means of transport. Finally I address the issue of the ‘global village’
  • It is clear from our current scientific understanding that global warming poses a global challenge, which must be met by global solutions.

Chapter 2: The Greenhouse Effect

The basic principle of global warming can be understood by considering the radiation energy from the sun which warms the earth’s surface and the thermal radiation from the Earth and the atmosphere which is radiated out to space. On balance these two radiation streams must balance. If the balance is disturbed (for instance by an increase in atmospheric carbon dioxide) it can be restored by an increase in the Earth’s surface temperature.

Chapter 3: The Greenhouse Gases

The greenhouse gases are those gases in the atmosphere which, by absorbing thermal radiation emitted by the Earth’s surface, have a blanketing effect upon it. The most important of the greenhouse gases is water vapour, but its amount in the atmosphere is not changing directly because of human activities. The important greenhouse gases which are directly influenced by human activities are carbon dioxide, methane, nitrous oxide, the chlorofluorocarbons (CFCs) and ozone. This chapter will describe what is known about the origin of these gases, how their concentration in the atmosphere is changing and how it is controlled. Also considered will be particles in the atmosphere of anthropogenic origin which can cool the surface.

Chapter 4: Climates of the Past

To obtain some perspective against which to view future climate change, it is helpful to look at some of the climate changes which have occurred in the past. This chapter will briefly consider climatic records and climate changes in three periods: the last hundred years, then the last thousand years and finally the last million years. At the end of the chapter some interesting recent evidence for the existence of relatively rapid climate change at various times during the past one or two hundred thousand years will be presented.

The last hundred years

  • The 1980s and early 1990s have brought some unusually warm years for the globe as a whole (see Chapter 1); eight of the nine warmest years during the past century have occurred during this period (up to and including 1995).
  • ‘Warmest’ means only a few tenths of a degree Celcius at most, but in terms of global averages such differences are quite significant. An increase of between 0.3 °C and 0.6 °C has taken place since 1860. Some periods of cooling as well as warming have taken place.
  • How can a global average changing by a few tenths of a degree have any meaning?
  • To estimate the changes over land, weather stations are chosen where consistent observations have been taken from the same location over a substantial proportion of the whole 130 year period.
  • Changes in sea surface temperature have been estimated by processing over sixty million observations from ships over the same period.
  • All the observations are then located within a grid of squares covering the Earth’s surface. Observations within each square are averaged; the global average is obtained by averaging (after weighting them by area) the averages for each of the squares.
  • Good agreement has been achieved between analyses carried out at different centers.
  • During the past twenty years or so observations have been made available from satellites orbiting around the earth, a comparatively short period in climate terms.
  • A careful analysis confirms that there is satisfactory agreement between the satellite and surface measurements.
  • Some variability arises through causes external to the atmosphere and the oceans. The low global average in 1992, compared with 1990, 1991, 1994 and 1995 is almost certainly due to the Pinatubo volcanic eruption.
  • The warming during the 20th century has not been uniform over the globe and there have been some areas of cooling. There is evidence that precipitation has increased over land in high latitudes of the northern hemisphere especially in winter.
  • The broad features of these changes in temperature and precipitation are consistent with what is expected because of the influence of increased greenhouse gases (see Chapter 6).
  • Minimum temperatures over land have increased about twice as much as maximum temperatures. An increase in cloud cover tends to obstruct daytime sunshine and to reduce the escape of terrestrial radiation at night.
  • The increase from 1910 to 1940 is too rapid to have been due to the rather small increase in greenhouse gases during that period.
  • From ice core data the 20th century temperatures are at least as warm as any century since 1400, and at some sites the 20th century appears to have been warmer than any century for some thousands of years.
  • The balance of evidence suggests that there is discernible human influence on global climate.
  • As greenhouse gases increase further, the amount of warming is expected to swamp the natural variation in climate.
  • Over the last hundred years sea level has risen by between 10 and 25 cm, due to thermal expansion of ocean water and from glaciers retreating.

The last thousand years

  • Professor Hubert Lamb of the Climatic Research Unit of the University of East Anglia has derived a record of the average temperatures for central England for the past thousand years.
  • Its main features are of a medieval warm period between AD1100 and 1300 when vines were grown as far north as Yorkshire, and the ‘Little Ice Age’ between AD1400 and 1850, during which freezing of the Thames in winter was not uncommon. Evidence suggests that the ‘Little Ice Age’ could have been experienced worldwide.
  • One of the largest eruptions during the period was that of Tambora in Indonesia in April 1815, which was followed in many places by two exceptionally cold years, described as the ‘year without a summer’. But the effect on the climate even of an eruption of the magnitude of Tambora only lasts a few years at most.
  • Although accurate direct measurements of solar output are not available apart from those made during the last two decades from satellite instruments, other evidence suggests that the solar output compared with its value today could have been significantly lower during the Maunder Minimum in the 17th century – a period when almost no sunspots were recorded.
Tuesday, April 20, 2010 @ 08:04 PM
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2010 Diary week 16

Book Review

Volcanic eruptions, global warming, climate change, weather extremes

This week there will be a break in book reviews on gardening, farming and food production to move on to books dealing with volcanic eruptions, global warming, climate change, weather extremes.

Global Warming: The Complete Briefing provides the basic information required to understand volcanic eruptions, global warming, climate change and weather extremes. Because this book is so helpful and comprehensive, it will be reviewed over two weeks. “Volcanoes inject enormous quantities of dust and gases into the upper atmosphere.” “One of the largest volcanic eruptions this century was that from Mount Pinatubo in the Philippines on 12 June 1991 which injected about 20 million tonnes of sulphur dioxide into the stratosphere together with enormous amounts of dust.” “The amount of radiation from the sun reaching the lower atmosphere fell by about 2% and global average temperatures fell by about a quarter of a degree Celcius for two years.” “The 1980s and early 1990s have brought some unusually warm years for the globe as a whole; eight of the nine warmest years during the past century have occurred during this period (up to and including 1995).” “‘Warmest’ means only a few tenths of a degree Celcius at most, but in terms of global averages such differences are quite significant. An increase of between 0.3 °C and 0.6 °C has taken place since 1860. Some periods of cooling as well as warming have taken place.” “The low global average temperature in 1992, compared with 1990, 1991, 1994 and 1995 is almost certainly due to the Pinatubo volcanic eruption.” “One of the largest eruptions during the last thousand years was that of Tambora in Indonesia in April 1815, which was followed in many places by two exceptionally cold years, described as the ‘year without a summer’.”

Tuesday, April 13, 2010 @ 07:04 AM
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FOREST FARMING

TOWARDS A SOLUTION TO PROBLEMS OF WORLD HUNGER AND CONSERVATION

J. SHOLTO DOUGLAS & ROBERT A de J. HART

INTERMEDIATE TECHNOLOGY PUBLICATIONS            REPRINTED 1985

Foreword by E. F. Schumacher

  • Ten years ago I received a book with the title Tree Crops A Permanent Agriculture, by J. Russell Smith that made sense because it did not merely state that ‘civilised man has marched across the face of the earth and left a desert in his footprints’ – a remark I had found confirmed in innumerable places throughout the world – but showed what could be done and what should be done.
  • Agriculture is for the plains, while silviculture is for the hills and mountains. When the plough invades the hills and mountains it destroys the land.
  • J. Russell Smith’s book made a tremendous impression on me. ‘Therefore, the crop-yielding tree offers the best medium for extending agriculture to the hills, to steep places, to rocky places, and to the lands where rainfall is deficient. New trees yielding annual crops need to be created for use on these four types of land.’
  • As my work took me all over the world, everywhere I could see it, thanks to Russell Smith: Agriculture in mountainous, rocky, or dry regions is a disaster, but trees are salvation. And ‘trees yielding annual crops’ did not have to be created; they existed already. But care and attention, selection and plant breeding, the application of methodical science, could improve them beyond our imagination.
  • I was fascinated with the work of Mr. P. A. Yeomans of Sydney, Australia, whose Keyline System seemed to me to possess the perfect beauty of truth.
  • All my life has been a journey of discovery of the generosity of nature. Traveling through India, I came to the conclusion that there was no salvation for India except through trees. There are trees for almost all human needs.
  • One of the greatest teachers of India was the Buddha who included in his teaching the obligation of every good Buddhist that he should plant and see to the establishment of one tree at least every five years. As long as this was observed, the whole large area of India was covered with trees, free of dust, with plenty of water, plenty of shade, plenty of food and materials.
  • Just imagine you could establish an ideology which made it obligatory for every able-bodied person in India, man, woman, and child, to do that little thing – to plant and see to the establishment of one tree a year, five years running.
  • This, in a five-year period, would give you 2,000 million established trees. Anyone can work it out on the back of an envelope that the economic value of such an enterprise, intelligently conducted, would be greater than anything that has ever been promised by any of India’s five-year plans.
  • It could be done without a penny of foreign aid; there is no problem of savings and investment. It would produce foodstuffs, fibres, building material, shade, water, almost anything that man really needs.
  • Finally, as a ‘fuel economist’, I should like to say that a most marvelous, three-dimensional, incredibly efficient contrivance already exists, more wonderful than anything man can make – the TREE. Agriculture collects solar energy two dimensionally; but silviculture collects it three-dimensionally. This, surely, is ‘the wave of the future.’
  • I do not think the authors of this book overstate their case when they say: ‘Of the world’s surface, only eight to ten per cent is at present used for food production. With the aid of trees, at least three quarters of the earth could supply human needs, not only of food but of clothing, fuel, shelter and other basic products.’
  • And they do not fail to add that wild life could be conserved, pollution decreased, and the beauty of many landscapes enhanced. This is the way, or at least one of the ways, to spiritual, moral, and cultural regeneration.

Introduction by J. Sholto Douglas

  • Trees constitute one of mankind’s most important assets and play a vital part in the maintenance of our environment. Indeed without them life on our planet could not survive.
  • At the same time, forests can contribute appreciably to world food supplies provided proper exploitation, combined with satisfactory conservation, is carried out. Moreover trees can flourish and yield abundantly in many places where arable crops and field grains would fail to grow.
  • This book discusses the role of forests and tree crops in farming and offers detailed advice and information on various economic species, the use of their products for food and raw materials, planting techniques and suggestions and guidance for the layout and operation of schemes of forest farming.
  • The aim of the work is to encourage the adoption of multiple-usage methods and to foster the integration of forestry with farming to form one pattern of agri-silviculture, wherever this may be appropriate.
  • It has been written simply, but it contains enough technical material to serve the purposes of agriculturists and forester in all countries and conditions, and seeks to provide useful guidance and practical instructions for extension workers, planners, government departments, institutions concerned with development and research, and indeed all those interested in tree-growing, whether they be laymen or professionals.
  • It is hoped that this work may be especially valuable to the developing nations in whose territories exist vast stretches of virtually uncultivated and desert or wasted lands, as well as to the more advanced countries where great areas of presently marginal value still lie neglected or require reclamation for economic use.
  • If, by means of forest farming, world production of foodstuffs and raw materials can be increased substantially and, where appropriate, tree crops linked with industrial development, something of real significance will have been achieved, both for the better sustenance of mankind and for the preservation and enhancement of our environment.

Introduction to New Edition by J. Sholto Douglas, January 1984

  • Hunger and malnutrition still affect vast numbers of people, while extensive tracts of land remain in wasted and degraded condition. Agriculture, as practiced today, cannot supply, on an economic basis, enough food to satisfy the needs of the poor, especially in less developed countries.
  • Since the Food and Agriculture Organisation of the United Nations, the World Bank, and the United Nations Development Programme were established not long after the Second World War, huge sums have been expended on their agricultural and related schemes and projects. In addition there has been a flow of aid. Yet more people than ever before are currently suffering from hunger and malnutrition.
  • The official organizations have also failed to deal with the problems of severe droughts, land deterioration, falling food production, loss of essential tree cover and damage to the rural environment.
  • By cutting trees, removing the protective mantle guarding our lands, man is creating droughts and causing the failure of traditional agriculture, especially in regions where the balance of Nature is most delicate. Destroy the world’s forests and we shall be destroyed too.
  • Forest farming is not a panacea for all the problems of world hunger, but it can make a very substantial contribution to human well-being.
  • Food, fuel and shelter are essential. Tree crops, in conjunction with arable and livestock husbandry, can provide a goodly part of our needs.

Chapter 1: Re-vitalising the Rural Areas

  • The most urgent task facing mankind today is to find a comprehensive solution to the problems of hunger and malnutrition, with all the disease and misery that they involve, by methods that do not overburden stocks of non-renewable resources, such as oil and minerals used for fertilizers, and do not impoverish the environment.
  • Vast areas of the world which are at present unproductive or under-productive – savannahs and virgin grasslands, jungles and marshes, barren uplands and rough grazings, deserts and farmlands abandoned owing to erosion – could be brought to life and made more hospitable to human settlement.
  • The ‘tool’ with the greatest potentials for feeding men and animals, for regenerating the soil, for restoring water-systems, for controlling floods and droughts, for creating more benevolent micro-climates and more comfortable and stimulating living conditions for humanity, is the tree.
  • Of the world’s surface, only eight to ten per cent is at present used for food production. Pioneer agriculturists and scientists have demonstrated the feasibility of growing food-yielding trees in the most unlikely locations – rocky mountainsides and deserts with an annual rainfall of only two to four inches.
  • With the aid of trees, at least three quarters of the earth could supply human needs, not only of food but of clothing, fuel, shelter and other basic products. At the same time wild-life could be conserved, pollution decreased, and the beauty of many landscapes enhanced, with consequent moral, spiritual and cultural benefits.
  • The production of essential foods by conventional methods is lagging so far behind the needs of the world’s rapidly growing population that even the advanced, industrialized, food-exporting countries are facing shortages of nutritional factors that are vital for health.
  • The toll of disease in the affluent countries which can be attributed to diet deficiencies or toxic elements in food or the environment is becoming comparable to the suffering caused by sheer malnutrition in the poorer countries.
  • There are few people on earth whose health and happiness could not be enhanced if they had access to a comprehensive, balanced, natural diet consisting largely of fresh products eaten direct from soil or tree.
  • At present, agriculture in most parts of the world is virtually exclusively geared to cereal growing and/or livestock rearing by conventional means.
  • Cereals and annual leguminous crops demand annual cultivations which are enormously expensive in labour or machinery, require large inputs of water and fertilizers, and are extremely vulnerable to the vagaries of the weather.
  • Through over-grazing, many regions, especially in the Sahel-Sudan zone of Africa, are degenerating into desert.
  • In the wealthier countries, livestock production, whether by traditional methods or modern factory farming systems, constitutes a serious drain on world stocks of cereals and protein needed for direct feeding to human beings.
  • The ‘Green Revolution’ – the breeding of high-yielding, hybrid cereals – heralded in the sixties as foreshadowing the end of the world food problem, has proved a disastrous failure in countries that have found themselves unable to afford the enormous fertilizer inputs that the new varieties demand. The new varieties also demand vast quantities of water.
  • In the light of the conspicuous failure of conventional agriculture to fulfill the nutritional needs of the world’s rapidly growing population, far-sighted agronomists in many countries are turning their attention to the numerous advantages of tree crops.
  • Trees offer the possibility of far higher food yields per acre. Whereas livestock rearing in temperate regions produces an average of about two hundredweight of meat per acre and cereal growing an average of about one and a half tons per acre, apple trees can yield at least seven tons per acre, while leguminous trees can provide fifteen to twenty tons of cereal-equivalent.
  • In tropical areas, and under conditions of multiple cropping – where trees are interplanted with vines, vegetables or cereals – far higher yields can be expected.
  • As a ‘machine’ for supplying the necessary factors for sustaining human and animal life, the tee, with its deep, ever-questing roots, seeking out the riches of the subsoil, and its mass of foliage high in the air, utilizing atmospheric minerals and solar radiation by the scientific process of photosynthesis, is far more efficient than any system devised by man.
  • Trees can tolerate conditions in which every other form of food production would be impossible, such as steep, rocky mountainsides.
  • Olives and carobs can be planted in the clefts of rocks where no soil at all is apparent; their roots will penetrate deep into the heart of a hillside until they find the nutritional elements they require.
  • Certain trees have roots which can penetrate as much as several hundred feet into the subsoil and rocky sub-strata in their search for subterranean water. The almond can survive and flourish in apparently waterless conditions where all other crops fail.
  • With their capacity for storing water for long periods, some species of trees and shrubs can survive extended droughts that kill all other forms of vegetable life.
  • Tree plantations are able to raise the entire water-table over a wide area, thus bringing the possibilities of conventional agriculture and horticulture to regions where such activities had been considered out of the question.
  • The water taken up by trees from the subsoil is transpired into the atmosphere and falls as rain. A single Eucalyptus tree forty feet high transpired eighty gallons of water a day.
  • Tree plantations also attract rain clouds and cause them to shed their loads, so that extensive tree growing can make a substantial contribution to the annual rainfall of a drought-ridden area.
  • Trees can be found which will tolerate both the rarefied air of great heights and the polluted atmosphere of industrial cities. Apple orchards have been established at heights of over 12,000 feet in Tibet and a honey locust was found in foggy London.
  • Better than any other crop, trees could supply the younger generation’s demand for self-sufficiency. Many suburban areas could produce more food than open countryside if the full tree-growing potentialities of private gardens were exploited.
  • Trees can be grown on the smallest or the largest scale; they are far less demanding in energy, machinery or irrigation than conventional agriculture, and far from damaging the environment, they conserve and improve both soil and water resources and purify the atmosphere.
  • In the 1930’s Toyohiko Kagawa recognized the necessity for restoring tree cover, suggested planting walnuts, the nuts to be used to feed pigs which could be sold as a source of cash income. The system became known as ‘forest farming’ or ‘three-dimensional forestry’, the three dimensions being conservation, tree crops and livestock.
  • The concept was used in the semi-arid area of the middle Limpopo valley in South Africa where the carob and algarroba, both of which yield large crops of edible beans which, when ground into meal, are excellent for cattle fodder and human food.
  • The general pattern of three-dimensional forestry is to have large belts or blocks of economic trees interspersed with narrower grazing strips of grasses or other herbage along which move herds of livestock, fed from the woodlands, and producing meat, milk, eggs, wool and other items.
  • The manure of the animals is returned to the soil and encourages healthy and vigorous growth of plants, thus reducing the need for bought-in fertilizers to a minimum.
  • Three dimensional forestry offers more than a system for satisfying man’s basic needs of food, fuel and other essentials. It offers a new way of life, which could provide rewarding and purposeful occupations for large populations.
  • By offering new schemes of land development the influx into the cities could be checked, and new, vital rural civilizations and cultures created.
  • E. F. Schumacher, in a speech in 1966, said: “The central economic task of mankind, at this juncture, is to build up an efficient and satisfactory way of life in rural areas, to achieve an agro-industrial structure which conquers rural unemployment, stops rural decay, and arrests the seemingly irresistible drift of destitute people from the countryside into the big cities, already overcrowded and rapidly becoming unmanageable.” Forest farming could make a considerable contribution to the fulfillment of this aim.
Tuesday, April 13, 2010 @ 07:04 AM
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2010 Diary week 15

The garden

With the warm weather following recent rain the grass has grown rapidly and needs continually attention. I have found the strimmer to be the most practical tool for keeping the property tidy. I have also been planting seeds and transplanting purchased plants – tomatoes, peppers and egg plants.

Book Review

Forest Farming points out that “civilised man has marched across the face of the earth and left a desert in his footprints.” “When the plough invades the hills and mountains it destroys the land.” “The crop-yielding tree offers the best medium for extending agriculture to the hills, to steep places, to rocky places, and to the lands where rainfall is deficient.” “One of the greatest teachers of India was the Buddha who included in his teaching the obligation of every good Buddhist that he should plant and see to the establishment of one tree at least every five years. As long as this was observed, the whole large area of India was covered with trees, free of dust, with plenty of water, plenty of shade, plenty of food and materials.” “Just imagine you could establish an ideology which made it obligatory for every able-bodied person in India, man, woman, and child, to do that little thing – to plant and see to the establishment of one tree a year, five years running. This, in a five-year period, would give you 2,000 million established trees. Anyone can work it out on the back of an envelope that the economic value of such an enterprise, intelligently conducted, would be greater than anything that has ever been promised by any of India’s five-year plans.”

Friday, April 9, 2010 @ 05:04 AM
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FOOD FROM DRYLAND GARDENS

AN ECOLOGICAL, NUTRITIONAL, AND SOCIAL APPROACH TO SMALL-SCALE HOUSEHOLD FOOD PRODUCTION

DAVID A. CLEVELAND & DANIELA SOLERI

CENTER FOR PEOPLE, FOOD & ENVIRONMENT                1991

Preface by James P. Grant, Executive Director, UNICEF

Household gardens are an important part of the indigenous agricultural production system in almost all developing countries. For poorer families, they typically make an important contribution to total household food intake, providing vital nutrients. Gardens also play a vital role in improving household wellbeing by providing income and savings, thus contributing to increased food security at the household level. All this has often been neglected or misunderstood by development planners. Food from Dryland Gardens will help to change this misunderstanding.

The publication of Food from Dryland Gardens is an important milestone in strengthening our understanding of and support for households in the Developing World. We, at UNICEF, are convinced that it will prove to be a key reference document for those individuals working in the fields of agriculture and nutrition. We are pleased to support its publication.

Let Us Hear From You by CPFE

The Center for People, Food and Environment (CPFE) is a non-profit organization devoted to research, education, and action for sustainable food systems. We believe that local control and self-reliance, social equity, cultural and biological diversity, and environmental conservation are essential ingredients of sustainable food systems.

Food from Dryland Gardens is the first major project of CPFE. The authors of this book are co-directors of CPFE. Organizations or individuals interested in knowing more about CPFE can write to us.

We hope that those of you who use this book will take the time to tell us what you find most helpful, and will give us your suggestions for improvements.

If you have information that is relevant, including your own reports and observations, we would appreciate hearing from you and receiving copies of written works. We have found four types of information most useful in writing this book: reports of basic or applied research relevant to dryland household gardens; reports of how people in drylands are gardening, and the impact of gardens on nutrition, income and community development; manuals for field workers in related areas such as irrigation; reports of garden projects, including brief personal narratives, giving some detailed information on assessment, implementation, and evaluation. We would be grateful for any information of this sort you could share with us. We will fully acknowledge the source if any of the information you send us is used in subsequent editions or other publications. So let us hear from you. Write to: CPFE, 344 South Third Avenue, Tucson, Arizona 85701, USA

How to Use This Book

  • This book is organized into four parts: Part I (Chapters 2-4) gives an overview of gardens in development and background information important for supporting gardens; Part II: (Chapters 5-13) is about growing gardens; Part III (Chapters 14-16) discusses using the harvest from gardens; and Part IV (Chapters 17-20, plus an index) contains information on measurements, resources, and the complete list of references, some of which are annotated.

Chapter 1: Introduction

  • On the outskirts of a city in northern Egypt, Hopi women in northern Arizona, inside a home compound in northern Pakistan, a slum woman in Mexico City, in the savanna of northern Ghana, people are all gardening – in the wet season, in the dry season; in cities and in rural areas.
  • The crops and varieties they grow are chosen primarily from among those that have been handed down from parents and grandparents. They are adapted to climate and soils, resistant to local insects and diseases, and are easy-to-cook, good-tasting ingredients of the meals that are part of their cultural identity.
  • In this book Third World does not refer to a geographical region but to a situation where communities are not in control of their own resources, and are often exploited by outside markets, organizations, or governments on which they are dependent.
  • The Third World includes not only the majority of the population in Africa, Asia, and Latin America, but also many communities within the rich industrialized nations.
  • Food from Dryland Gardens was written to encourage gardens that serve local needs, that are based on local knowledge and resources, and that conserve natural resources and the biological diversity of traditional crops.
  • We emphasize long-term environmental and social sustainability, meaning the management of soil, water, and biological resources so that all future generations can also use them.
  • To improve the well-being of the poor and hungry of the drylands their needs, desires, resources, and skills must be kept at the center of the project and they must have control over changes affecting them.
  • Like other improvements, gardens promoted in this way may not produce showy and spectacular results at the beginning, but are more likely to respond to real needs, and persist and grow beyond the life of the project.

PART I: GARDENS AS A DEVELOPMENT STRATEGY

  • To be sustainable, development that involves outsiders must be a cooperative venture; local people guide the process while project workers are resources. Project workers must learn to work with community members as equals, respect and support local skills and knowledge and keep in mind the ultimate goal of improving people’s well-being in a way that is both socially and environmentally sustainable.
  • Industrial gardens are usually based on approaches that are inappropriate for the local situation and are not sustainable.
  • Colonialism contributed to the belief still held by many today that indigenous food production expertise in the Third World is inferior and not suited to the modern world, and industrial, large-scale, capital-and resource-intensive agriculture is the only way to improve the situation.
  • While development strategies like the ‘green revolution,’ which are based on an industrial agriculture model, sometimes result in increased production, they have often led to increased inequities in the Third World countries where they have been applied.
  • These strategies have frequently perpetuated dependence on the industrialized nations and the international markets they control. Meanwhile, malnutrition and poverty persist as major problems.
  • The assumption follows that indigenous gardens are not based on scientific principles. Yet nothing could be further from the truth. The more that is learned about indigenous food production, the more obvious it is that it is based on the same principles as Western science.
  • Western agricultural science is very much under the influence of a world economic system that emphasizes maximizing production and profits. The majority of research carried out is on strategies that increase farmer dependence on the market.
  • While the problems of powerlessness facing the poor in drylands can only be eliminated by addressing their social and economic roots in colonialism, global inequity, and dependency, gardens can provide immediate benefits, and most importantly, can provide those benefits in a way that contributes to the solution of the larger problems.

Chapter 2: Gardens and Nutrition in Drylands

  • Good nutrition is essential for good health. Malnutrition, the lack of required nutrients, is a major problem in drylands, especially for poor households. Malnourished people are more vulnerable to disease; at the same time disease often contributes to malnutrition.
  • People suffering from disease and malnutrition are not able to work as productively as healthy, well-nourished people. This increases dependence on outside help and reduces the quality of life. This can become a self-perpetuating cycle that affects a household, a community, and even a nation.
  • In this book we apply the concepts of nutrition to both plants and people. In Part II we discuss the nutritional needs of plants, sources of these nutrients, and the effects of nutrient deficiencies.
  • Gardens can provide nutrients, increase household income or savings which may be used to improve nutrition (Chapter 3).
  • The nutritional effects of processing and preserving garden produce are discussed in Chapter 15 and the preparation of weaning foods from the garden in Chapter 16.
  • There is a growing recognition that assumptions about ‘development’ and ‘progress’ in diets, lifestyle, and agriculture that are modeled on Western, industrialized countries must be carefully re-examined.
  • Malnutrition is not simply a matter of inappropriate or inadequate food. It is also a consequence of policies and assumptions at the local, regional, national, and global levels that affect the production, processing, promotion, and distribution of food.

2.1 Summary

Children, sick people, and pregnant and breast-feeding women need extra nutrients to avoid becoming malnourished. Those working hard in the home, field, or factory also need extra food. Food consumption and distribution is determined not only by need, but by beliefs and traditional dietary patterns, and by patterns of control over resources in the household, the community, the nation, and the world.

Energy, protein, vitamins A, C, D, folacin, thiamine, riboflavin, and niacin, and minerals such as iron, zinc, and calcium are nutrients essential for good health – however they are often inadequate in dryland diets. Gardens are good sources for many of these nutrients.

Anti-nutrients are substances in food that are poisonous or that reduce nutritional value, and are present in all diets. Traditional processing techniques often help eliminate these.

2.2 Recommended Dietary Allowances and the Nutrient Content of Foods

Table 2.2 Rich Garden Sources of Some nutrients

2.3 Special Nutritional Needs in Drylands

2.4 Energy

2.5 Protein

2.6 Vitamins

2.7 Minerals

2.8 Fats

2.9 Fiber

2.10 Anti-Nutrients

2.11 The Effects of Gardens on Nutrition

  • Gardens can make a significant contribution to solving three of the most important dryland nutritional problems: PEM of infants and children, vitamin A deficiency, and anemia resulting from lack of iron and vitamin C.
  • When gardens can be grown their influence on nutritional status of household members depends on many factors including: the amount of different foods harvested; the quantity and quality of the nutrients; the availability of nutrients in garden produce; methods of storage and processing; distribution of garden produce to different members of the household; the amount of produce sold and not consumed by the household; the way food is combined with other foods; the health and activity of household members.
  • Many of the dryland crops that are excellent sources of energy, protein, vitamins, minerals, fats, and fiber have been presented in sections 2.4 to 2.9. In the following sections we discuss the nutrient yields of gardens and the contribution of gardens to nutrition.

Chapter 3: Gardens, Economics and Marketing

  • One reason why many people garden is because of the income they can earn by marketing garden products.
  • The important questions are: what are the economic contributions of existing gardens? Can they be improved, and, if so, how? Under what conditions will gardens make economic sense for households that do not have them?
  • We believe that economic development should be: environmentally sustainable by not destroying resources that will be needed by future generations; socially sustainable by providing benefits equitably, which may include redistribution of control over resources.
  • To meet these goals development projects should: encourage local self-reliance by building on local knowledge and resources; encourage both biological and cultural diversity; encourage community organizations that place a priority on social well-being.

3.1 Summary

Gardens provide both income and savings, but their effects on the whole household or individual household members depend on many factors both within and beyond the household. To contribute to sustainable development, each garden or garden project needs to be adapted to the local social system and environment, and not based on the faulty assumptions of conventional economics. This demands an understanding of gardeners’ economic decision making and the forces that affect it. For example, while women are often the gardeners in the household, they may not have control over productive sources like land, or over income from marketing garden produce. Marketing and processing techniques can help reduce gardeners’ risks and to increase benefits to the household. Forming cooperatives can spread risks and is often an appropriate way to organize market gardening. In many places indigenous or spontaneous social groups become the basis for successful marketing cooperatives.

Chapter 4: Assessment Techniques

4.1 Summary

  • An assessment gathers information about local conditions, needs, and resources and is a vital part of planning for any project. In addition, assessments are valuable for monitoring projects while in progress and for evaluating their impact after completion.
  • Different individuals and groups have different perspectives on local conditions and different ideas about how projects should be done. All perspectives are useful but the views of the community members, especially those who will be directly affected, are most important.

PART II: GARDEN MANAGEMENT

Chapter 5: How Plants Live and Grow

Chapter 6: Growing Plants From Seeds

Chapter 7: Vegetative Propagation

Chapter 8: Plant Management

Chapter 9: Soils in the Garden

Chapter 10: Water, Soils, and Plants

Chapter 11: Sources of Water for the Garden

Chapter 12: Irrigation and Water-Lifting

Chapter 13: Pest and Disease Management

PART III: GARDEN HARVEST

Chapter 14: Saving Seeds for Planting

Chapter 15: Processing, Storing, and Marketing Food from the Garden

Chapter 16: Weaning Foods from the Garden

PART IV: RESOURCES

Chapter 17: Glossary

Chapter 18: Some Crops for Dryland Gardens

Chapter 19: Resource Organizations

Chapter 20: References

Index

Friday, April 9, 2010 @ 05:04 AM
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2010 Diary week 14

Gardening

The weather has turned warm. We have been planting purchased plants and seeds ready for later transplanting.

Book Review

Last week Pillar of Sand: Can the Irrigation Miracle Last? pointed out that between 1951 and 1985, Israel expanded its irrigated area fivefold with only a threefold increase in water use. Output per cubic meter nearly tripled and the value of output (in real terms) jumped 10-fold. Israel is the only nation that appears to have done what the world needs to do over the next 30-40 years – double water productivity in agriculture.

The authors of Food from Dryland Gardens “believe that local control and self-reliance, social equity, cultural and biological diversity, and environmental conservation are essential ingredients of sustainable food systems.” “We have found four types of information most useful in writing this book: reports of basic or applied research relevant to dryland household gardens; reports of how people in drylands are gardening, and the impact of gardens on nutrition, income and community development; manuals for field workers in related areas such as irrigation; reports of garden projects, including brief personal narratives, giving some detailed information on assessment, implementation, and evaluation.”

Monday, April 5, 2010 @ 10:04 PM
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Ioannis Monogios, Christine, Klio Natsi and George Politis all members of SKETBE

Christine and David with Klio Natsi

Its been a wonderful and full two weeks with several exhibits opening in different places.  On March 24th we had the opening of the Byzantine Ceramics Exhibit in the new cultural center of Toumba in Thessaloniki.  This exhibit was in conjunction with a group of Byzantine Iconographers and so vice mayor Mr. Gakis was present and there was a good tunout.  Then on Friday we drove up to Ioannina where the miniature exhibit was opening in a lovely gallery called Technoxoros.  I also had a piece, the Dancing Ladies, in a SKETBE exhibit at the Bank of Pireos which is now moving to Naoussa and opening there next Friday, April 9.

The show in Toumba will remain open until Wednesday April 14.

With Vanna, Niko and VassoChristine and David with Klio NatsiIoannis Monogios, Christine, Klio Natsi and George Politis all members of SKETBE6 of the 31 pieces on a maroon background

6 of the 31 pieces on a maroon background