Food production and the food chain: The main numbers: Solar radiation impacting on Earth –178,000 terawatts (a terawatt is 10 12 watts) annually Capture.

Slides:



Advertisements
Similar presentations
Farmland…Uses and Challenges. Farmlands: Land that is used to grow crops and fruit The United States contains more than 100 million hectares of farmland.
Advertisements

Balancing Biomass for Bioenergy and Conserving the Soil Resource Jane Johnson USDA-ARS- North Central Soil Conservation Research Laboratory.
Scotland’s Food System at a Crossroads David Atkinson Food and Drink Leadership Forum & ACTS Rural Committee.
Ecological Footprint. Definition of Ecological Footprint “area of land in the same vicinity as the population that would be required to: –1) provide all.
Chapter 1 Environmental Problems, Their Causes, and Sustainability
Feeding the world involves soil and water resources, food production, social and cultural issues, food distribution and environmental impacts.
Introductions BIOL1040 Environmental Science.
The Kyoto Protocol Reaching Global Agreements 1997.
Human Impact on Ecosystems
Food and Agriculture Chapter 15.
Chapter 1: Environmental Problems, Their Causes and Sustainability
Ecosystems Essential Questions:  What limits the production in ecosystems?  How do nutrients move in the ecosystem?  How does energy move through.
AP Environmental Science
Human Impacts on the Environment
Earth’s human population continues to grow.
MEAT IS THE PROBLEM. Human population: 6.9 Billion Estimated total human biomass: 50 kg * 6.9 Billion = 345 million metric tons The REAL population bomb…
UK Renewable Energy Policy with particular reference to bioenergy
Energy Resources.
Environmental Science Chapter 1 Notes
What is going on in the cartoon? This is an example of Deforestation. As the human population grows, so does the demand for Earth’s resources.
STANDARD 2.8 (9%-14%) Evaluate human behaviors in terms of how likely they are to ensure the ability to live sustainably on Earth.
Environmental Science Chapter 1 Notes. Environmental Science: Is a multidisciplinary field that draws from all sciences (as well as other fields) Is considered.
APES INTRODUCTION TO AP ENVIRONMENTAL. INTRODUCTION TO ENVIRONMENTAL SCIENCE Environment External conditions that affect living organisms Ecology Study.
Ecological Footprint If current material and population growth trends continue and population stabilizes at 10 billion people in 2040, we will need between.
Environmental Problems, Their Causes, and Sustainability Chapter 1.
DO NOW Journal Entry – answer the following: Journal Entry – answer the following: What is environmental science?
Productivity and Efficiency in Biosystem inputoutput productivityEfficiency Designed Control.
Ecological Footprint & Sustainability
Human Impact on Ecosystems
Ecology Organisms. Niche It is an organisms role in the community. It includes: –what it eats –What eats it –What and how much resources it uses Can you.
environmentally sustainable society A Society that satisfies the basic needs of its people without depleting or degrading its natural resources and thereby.
Earth’s human population continues to grow.
Environmental Problems, Their Causes, and Sustainability.
Science and the Environment Chapter 1 Section 1: Understanding Our Environment Section 2: The Environment and Society Chapter 1 Section 1: Understanding.
1 Understanding Our Environment. 2 Environmental Science.
World Environmental Issues
Chapter 16 Human Impact on Ecosystems
How nature works. How the environment effects us. How we effect the environment. How we can live more sustainably without degrading our life-support.
What is a renewable energy? -Resource that can be replenished rapidly through natural processes as long as it is not used up faster than it is replaced.
HUMAN IMPACT ON ECOSYSTEMS Chapter 6 Day 1 Human Ecological Footprint Map Humans have influenced 83% of Earth’s surface based on population, travel.
Ecological Integrity of Earth The Earth Systems - ecosystem services Those natural processes and systems that sustain life on earth Life support systems.
Ch 3 Ecosystems: What They Are and How Do They Work?
Genetically modified crops and foods have advantages and disadvantages.
Lesson 1 Identifying Environmental and Economic Impacts from Soil Erosion.
Natural Capital and Sustainability. Natural Capital includes the core and crust of the earth, the biosphere itself - teaming with forests, grasslands,
Chapter 16, sections 1, 2, 3, 5 Biology Unit 2: Human Impact on Ecosystems 1.
Flows of Energy and Matter. Significant Ideas Ecosystems are linked together by energy and matter flows. The Sun’s energy drives these flows, and humans.
Objectives Explain how the rate of human population growth is determined and compare the rates of growth over the last 100 years Distinguish between people.
Learning Target: Human Population Growth Humans: Where do we go from here? ?
Review Water Resources 2.5% of the Earth’s water is fresh water. – 70% of that is ice caps and glaciers – Almost 30% is ground water – Remainder.
Ch 14: Agricultural Methods and Pest Management. Outline 14.1 The Development of Agriculture 14.2 Fertilizer and Agriculture 14.3 Agricultural Chemical.
CHAPTER 1 UNDERSTANDING THE ENVIRONMENT. SECTION 1 WHAT IS ENVIRONMENTAL SCIENCE? The study of the impact of humans on the environment.
Our Island, Earth Chapter 1 Section 1.1.
Environmental Science Chapter 1 Notes 1. Section 1: Science and the Environment 2.
APES INTRODUCTION TO AP ENVIRONMENTAL SCIENCE. INTRODUCTION TO ENVIRONMENTAL SCIENCE Environment External conditions that affect living organisms Ecology.
Consider this... There are many indications that human population is pushing up against the limits of the Earth’s resources: The number of starving people.
Chapter 1 Science and the Environment.  Environment – everything around us, including natural and man-made  Complex web of relationships connecting.
SUSTAINING THE EARTH MILLER/SPOOLMAN 10 TH Resources – natural capital.
Understanding Our Environment. What is environmental science? Environment: the conditions that surround an organism or group of organisms Environmental.
HUMAN POPULATION & SUSTAINABILITY. HUMAN POPULATION - HISTORY Homo sapien sapien “wise man” 250,000 – 500,000 years ago Hunter-gather populations considered.
Bell Work Define what you think an indicator is.
Introduction to Resources and Ecological Footprint
Unit Food supply, plant growth and productivity
Section 16.1: Human Population Growth and Natural Resources
Biology Chapter Sixteen: Human Impact on Ecosystems
Human Impact on Ecosystems
Resource consumption.
                                .
GLOBAL EFFECTS.
                                .
Presentation transcript:

Food production and the food chain: The main numbers: Solar radiation impacting on Earth –178,000 terawatts (a terawatt is watts) annually Capture of this energy by plants and algae (both terrestrial and marine) –100 to 120 terawatts annually 6 terawatts on arable land 12 terawatts on grassland or savanna 50 terawatts in forest Question: –What can we therefore say about plant productivity in terms of its ability to supply the total energy used by humankind?

Food production and the food chain: The main numbers: >120,000 terawatts ~ 55,000 terawatts left ~ 40,000 terawatts in Hydrological cycle Of which % “could” be captured by hydro Global energy consumption by man: 15 terawatts Capture by plants: 120 terawatts

Food production and the food chain: Photosynthetic conversion by plants –More energy is landing on the plant than is captured by it. –3-6% of incoming solar radiation impacting on the plant is captured. –Perhaps 1/3 to 1/5 of this is stored by the plant (grain, tuber, stem, root etc.) giving an overall conversion efficiency of about 1%. The hidden energy needed by plants –Approx 1000kg of water is transpired for each kg of biomass produced by a plant. This energy also comes from the sun via the hydrologic cycle. –The solar energy from the hydrologic cycle needed to produce this transpiration is more than 100 times the energy contained in the plant biomass. Question: –In terms of the energy required by a plant to produce biomass, which is greater; photosynthetic or hydrologic?

What proportion of total energy consumption is actually used in food production? Global energy consumption by man –15 terawatts (~475 exajoules) Direct Agricultural use: –Only 1-2 % of this globally (e.g. ~1.2 exajoules in USA) Question: –What can we say about total plant productivity and its ability to provide energy used in primary agriculture?

How does global food requirement compare with photosynthetic output? Each human requires about 10MJ of food energy per day This is about 22 exajoules planet-wide per year On an annual basis this is currently equivalent to 0.7 terawatts Or less than 1/20 of total global energy use by humans Or ~0.7% of global photosynthesis Or ~12% of the photosynthetic product captured by plants on arable land worldwide

How much of the World’s photosynthetically active land base is agricultural? Total land: –13 billion hectares Agricultural land –5 billion hectares Arable: 1.5 billion ha (potentially more productive) Grassland: 3.5 billion ha (for feeding animals which we can then consume) Question: –Where does this leave agricultural capacity in terms of its ability to produce enough food now and in the future? –To answer this we need more information

Photosynthetically active land base and soil degradation

Enough food for now and into the future: Population Current world population: –6 billion Projected population for 2050: –7.7 (L) –9.4 (M) –11.2 (H) Question: –Assuming medium growth, how much more food will be required by 2050?

Enough food for now and into the future: Diet Global food requirement expressed in grain equivalents (billion tons d.w. per year). Vegetarian diet –Today’s population: 2.9 –2050 (M): 4.5 Moderate diet –Today’s population: 5.2 –2050 (M): 8.2 Affluent diet –Today’s population: 9.1 –2050 (M): 14.4 Question: How does this compare with current food production? –Answer: 4.5 currently

What is the potential food production? If all current agricultural land were operated using maximum inputs (including irrigation), to a level equivalent to the most productive European fields: –Then (theoretically) actual productivity could be ten times higher than now If potentially productive non-agricultural land were brought into agriculture, this would increase by a further 50% Even using low inputs, potential agricultural productivity could be four times higher than now. –But if this potential is there, why is there no sign of it being realized?

Need for food: Theory versus practice From slide 5: –22 exajoules needed (in theory) to feed current population In reality, more is needed, to allow for waste, after-harvest losses, distribution inequalities etc. From slide 9: –4.5 billion tons grain equivalent of food produced each year. –Very broadly, this equates to exajoules annual production. So currently, at least twice the theoretical need is being produced to feed World population. From slide 2: –Energy capture on agricultural land: 500 exajoules Existing productivity is much lower than indicated on slide 2.

Efficiency in food: Developing versus developed World? 1999 data for World energy use, energy use in primary agriculture, and food energy produced (at consumption point). Total energy use Energy use in primary agriculture Food energy produced Energy efficiency World300 EJ7 EJ25 EJ1:3.5 Developed countries 175 EJ3.7 EJ6 EJ1:1.6 Developing countries 125 EJ3.2 EJ19 EJ1:6

And what of energy used in food; is this sustainable? Energy required to produce food in a Western society (1990) Item of energy useMJ/person/day% of total Used on the farm6MJ Farm inputs8MJ Processing26MJ Transport to market20MJ Wholesale and retail15MJ Used in the home for food25MJ Total100MJ100 Energy contained in food eaten 10MJ

So if the whole World moves to an affluent diet and high input systems, do we have enough fuel? From slide 5: –22 exajoules needed (in theory) to feed current population But, if everyone on the planet needed 10 units of fossil fuel energy for each unit of food energy we consume, then the real energy need is 220 exajoules And, if everyone on the planet over-fed themselves to the extent that Western society now does, then the real energy need rises to 330 exajoules And if the population increases by 50%, this brings the total energy need to 445 exajoules Question: –Is there enough fossil fuel for this? –Could biofuels be the answer?

Is there enough fossil fuel; how much of current fossil fuel use is devoted to food production? Assume 450 exajoules (EJ) of fossil fuels are needed for food production, distribution etc. in a year (i.e. everyone follows the western model) –This is in excess of current total energy from oil extracted annually (which is about 150 EJ per year) –Energy from gas constitutes 100 EJ per year –Energy from coal contributes an extra 125 EJ per year –Renewables and nuclear contribute another 60 (about 50/50) However, remember that right now 80% of fossil fuel use in the developed World is not used for food production or the food chain. If this rate were applied to the figures above, then 2000 EJ per year would be required for World use; more than four times the current use. Compare this to the current figure of 90EJ fossil fuel used in the food production system.

Is there enough potential biofuel? Large variations in estimates of biomass biofuels: –IPCC (2000) 334million 24t/ha/yr. = 107 EJ/yr. (assuming 18MJ/kg dry matter) –Higher estimates pre-date this one, mostly based on more available land, but lower yields. –The IPCC yield estimate seems very optimistic. –The amount of land available for biofuel could be increased by making existing farmland more productive. However, this typically requires further energy inputs.

This is just energy sustainability – what about other considerations? Water depletion –Water from many aquifers is being used more quickly than it is being replaced. Water pollution –Groundwater contamination with fertilisers, agrochemicals. Tolyfluanid plus ozone treatment creates nitrosamines Glyphosate in ground water Simazine –45% of wells in potato and fruit growing area of Portugal Soil erosion –The dust bowl Atmospheric pollution CO2 and climate change Destruction of habitats

Some examples… ‘Dust Bowl’ USA 1930’s NOAA Photo Library

500,000 homeless ‘environmental refugees’

CO2 in the atmosphere

Carbon flows 1 petagram = 1 billion tonnes

Integrated into an Ecological footprint Kitzes et al Shrink and share: humanity’s present and future ecological footprint. Phil. Trans. R. Soc. B. 363,

Ecological footprint: why the Western World needs to act Kitzes et al Shrink and share: humanity’s present and future ecological footprint. Phil. Trans. R. Soc. B. 363,

Silver bullet: What about new food production technologies? The current proposition is that GM technology may lead to the next “great leap forward” in plant productivity Thus far, despite 20 years of trying, GM crops produce lower yields than conventionally bred. GM crops modified to resist herbicides have resulted in significant increases in herbicide usage. Environmental damage due to GM technology and the monocultures it promotes has been reported, but not studied in depth. Like any technology, genetic modification of plants can be used for the benefit of many or few. The privatisation of this technology via plant patents and de-regulation has meant only benefits for the companies involved, and not for humanity.

A warning Easter Island