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Impact of agriculture on climate change Agriculture and forestry are responsible for about 30% of greenhouse gas emissions through loss of carbon from soils and vegetation agricultural activities that produce GHGs such as methane (CH4) and nitrous oxides (NOx) Growing demand for food is the dominant driver of the development and expansion in agriculture and deforestation An indicator of available food in the world is the amount of grains (cereals) available Focus on three main cereal crops: maize, wheat, and rice because they supply half of the energy required by a person An active, healthy adult requires 2000 to 3000 Calories per day note: 1 Calorie = 1000 calorie = 1 kcal Malaysia: 2,901 Calories per capita calorie content (per 100 g): maize = 355, rice = 325, wheat = 341 vegetables and fruits = < 100 potatoes = 77 Land use trends Agriculture land covers 5 billion hectares (about onethird or 35% of Earth’s ice-free land area) 1.5 billion ha of cropland (11% of the Earth's ice-free land surface) 3.5 billion ha of rangeland (pasture) (25%) Changes have occurred between forested land to agricultural land (cropland and rangeland) due to increase in the world population and the demand for food Over the last 40 years agricultural land has increased by about 500 million hectare (Mha) or 10% half of this increase came from deforested land Global agricultural cropland area distribution Ramankutty, N.; Evan, A.T., Monfreda, C. and Foley, J.A. (2008). "Farming the planet: 1. Geographic distribution of global agricultural lands in the year 2000". Global Biogeochemical Cycles 22: GB1003. Global agricultural rangeland area distribution Ramankutty, N.; Evan, A.T., Monfreda, C. and Foley, J.A. (2008). "Farming the planet: 1. Geographic distribution of global agricultural lands in the year 2000". Global Biogeochemical Cycles 22: GB1003. Bert Metz, 2010, Controlling Climate Change, Cambridge University Press, Cambridge Challenges and effects The following are the challenges faced by agriculture today, and how they cause, either directly or indirectly, detrimental climate change: 1. Falling crop productivity 2. Over-dependency on fossil fuel (oil) for energy 3. Increasing demand for meat 4. Increasing world population 5. Competition between food and biofuel crops 6. Deforestation Falling crop productivity Green Revolution In the 1950-60s, poor yields in India, Africa, and Mexico caused problems of world food shortages and starvations But in the late 1960s, Green Revolution brought huge increases in crop yields primarily through improved crop varieties Mexico: wheat yields 6x more than 1944 yields India: wheat yields 2x more between 1965-72 As a result, world famine was greatly alleviated as there was plentiful of food (with the exception of some parts in Africa), and food prices fell To many governments, it appeared then that our problem of food supply was over Diminishing returns Grain yields increased impressively throughout the 1970s and 1980s, but since then, yield increases are no longer as large as they once were Grain production per person, for instance, peaked at 346 kilograms in 1984, fell to less than 300 kilograms today, and is expected to be at 247 kilograms in 2020 Before 1984, total grain production increased 3% per year. Now, it is increases at average of 1.6% only OUTPUT approaching the end, smaller increases at the beginning, large increases INPUT Falling increase in world crop productivity 3.5 3.0 3.2 2.7 2.5 2.0 2.2 2.0 2.1 2.0 1.8 1.7 1981-2000 1.3 1.5 1961-1980 2001-2008 1.0 0.5 0.0 Maize Rice Wheat Biological limit It appears we have reached the limits of Green Revolution Extra fertiliser and water brought increased yields but with diminishing returns (not as high or as dramatic as before) Plants, given their current physiology and genetic makeup, can only produce so much Adding increasingly more inputs only continues to push against the ceiling—the plant’s photosynthetic limits biological limit: further inputs will no longer enhance yields or smaller increases Over-dependency on fossil fuel for energy 50-year dependency on oil Oil is the lifeblood of the global economy Agriculture is heavily dependent on oil fertilizers, herbicides, and pesticides fuel for machinery fuel for transportation food processing electricity especially for controlled climate conditions hydroponics, aeroponics, artificial lighting, egg incubators, other machinery High inputs Agriculture is heavily dependent on inputs such as fertilizers and pesticides (including herbicides) to increase and protect crop yields typically over one-third of the total cost of farm expenditure Fertilisers and pesticides are made from fossil fuels Nitrogen is one major nutrient for plant growth, but N exists as inert (very stable) gas To make nitrogen fertilizer (like urea), high temperature and pressure needed to break apart the N2 gas (break the triple bond) where to get that energy to produce that high temperature and high pressure to break the bonds? answer: fossil fuel Fertiliser use The use of fertilisers for the world, for instance, increased by 55% from 1971 to 2007 in just ten years from 1995/96 to 2005/06, the fertiliser use in Malaysia increased by a staggering 66%, making it one of the largest rise in the world In 2009: 3.5 billion tonnes of fertilizers imported by Malaysia, of that amount: 90% is for oil palm 5% is for rubber and cocoa 5% is for vegetables, rice, and fruits Worldwide fertiliser use http://www.nytimes.com Pesticide use Worldwide, pesticide use increases 2 to 5 percent annually Malaysia sees a slightly higher increase of 3 to 9 percent each year Malaysia has one of the highest pesticide use per hectare of agriculture land in the world (more than 23 kilograms of active ingredient per hectare), second only to South Korea in the Asia region world average is only 2 kg active ingredient per hectare “Food miles” Food miles total distance the food has to travel to reach the consumers Lots of food shuttling very dependent on transportation = more dependency on fossil fuels favourite food items such as apples, oranges and grapes, to name just a few, are commonly seen in the Malaysian market all year round. Such food items are transported over long distance, often by airfreight, from their respective countries to reach our shores Inefficient food distribution system that means wasteful and expensive use of energy US food transportation http://attra.ncat.org/attra-pub/foodmiles.html Increasing world population World population currently stands at about 6.7 billion and is expected to rise to about 9 billion in 2050 after which world population will decline gradually http://www.census.gov/ipc/www/idb/worldpopgraph.php After rapid increases from 1900s to 1960, world population growth rate is now declining. In 2008, world population growth rate is 1.17% http://upload.wikimedia.org/wikipedia/en/1/13/World_population_growth_rates_1800-2005.png World population density (2006) persons per square kilometer Malaysia: 84 persons per square km (2008 data) http://www.mapsharing.org/MS-maps/map-pages-worldmap/6-world-map-population-density.html City lights, Aug 15, 2003 http://science.nasa.gov/ World total fertility rate (TFR) Years TFR Years TFR 1950–1955 4.92 2000–2005 2.67 1955–1960 4.81 2005–2010 2.56 1960–1965 4.91 2010–2015 2.49 1965–1970 4.78 2015–2020 2.40 1970–1975 4.32 2020–2025 2.30 1975–1980 3.83 2025–2030 2.21 1980–1985 3.61 2030–2035 2.15 1985–1990 3.43 2035–2040 2.1 1990–1995 3.08 2040–2045 2.15 1995–2000 2.82 2045–2050 2.02 projected Malaysia’s fertility rate Malaysia has the same fertility rate as the world average http://data.worldbank.org Malaysia’s statistics Malaysia Population 30.0 million people 25.0 20.0 15.0 10.0 5.0 0.0 1960 1970 1980 1990 2000 2010 2020 Year • one birth for every 58 seconds • one death for every 4 minutes and 36 seconds • one gain on net migration (International) for every 5 minutes and 15 seconds • overall increase in population, one person for every 56 seconds • annual increment rate: +1.7% Increasing demand for meat Increasing demand for meat From 1950 to 2000, meat intake per person grew from 17 to 38 kg per year The richer a nation, the more meat they eat! likewise, the richer you are, you eat more meat a country with a growing economy would see higher demand for meat About one third of world grain production is diverted to livestock feed, away from human consumption our food going to animals, but feed efficiency is low 1 kg animal feed does not give us 1 kg of meat Food fed to animals are made from grain (corn, rice, and wheat) For every 1 kilogram of beef, pork and chicken costs 7, 4 and 2 kilograms of grain feed, respectively. Meat production http://newscientist.com/ (Rich) China’s meat demand 1970 2008 China Europe US China Europe US 4 49 56 89 124 89 Annual meat demand (kg per capita) China: from 4 to 49 kg per capita; 12 times increase in 38 years! World average is 38 kg per capita Malaysia’s food consumption By 2020, Beef consumption to increase from 0.26 kg per capita in 2005 to 0.45 kg per capita Chicken consumption per capita to double From 1985 to 2000, Rice consumption declined 16% Wheat consumption increased 9% from 1985 to 2000 Fruit, vegetable and fish consumption doubled Chicken and beef consumption increased by 141 and 121%, respectively Competition between food and biofuel crops Biofuels Food crops grown for fuel Starch and cellulose from corn, sugar cane, cassava, coconut, wheat, sorghum, and soybean transesterification process to convert starch and cellulose into ethanol Oil palm and jatropha oil extracted as biodiesel (also a biofuel) oil palm has the highest oil production http://www.nrel.gov Jatropha http://www.bayercropscience.com/ http://www.treeoilsindia.com/ Previously considered as a weed. Seeds and leaves are poisonous. http://www.biodieselnow.com/b/site/archive/2009/06/17/daily-news-06-17.aspx 40 N/S 20 N/S L/ha L/ha http://www.thebioenergysite.com/articles/571/biodiesel-the-sustainability-dimensions Biofuel = carbon neutral? If harvesting is done sustainably, biofuel does not contribute to emissions CO2 is taken up in the vegetation burning causes CO2 emission so, no net CO2 emission: intake CO2 = outgoing CO2 But in reality this sustainability assumption is not met because of disturbance or fossil fuel use for maintenance, harvesting, and processing so biofuel can have a +ve net CO2 emission: emit more CO2 than that absorbed during photosynthesis High oil prices = more demand for biofuel crops High fuel prices have made the cultivation of biofuel crops extremely attractive forests are cleared for biofuel crops in farms, increasingly more tracts of land are dedicated to growing biofuel crops, reducing the land acreage that would otherwise be used to grow food before: all land area is for growing crop for food now: some land area is for growing crops for food, and the other is for fuel so, less food available In other words, there is a competition between biofuel and food crops The amount of corn required to fill up an SUV (Sports Utility Vehicle) tank just once is equivalent to feeding a person in Africa for one whole year If 100% jet fuel in a plane comes from oil palm biodiesel: every 1 km flight requires biodiesel from 2 or more oil palm trees to support the world aviation industry for a year, the total land area needed for oil palm is larger than whole of Malaysia Deforestation Deforestation Net loss of forest area (7.3 Mha/year) is the result of the difference between deforestation on average about 12.9 Mha/year between 2000 and 2005 and the increase in newly forested areas about 5.7 Mha/year The largest losses are found in South America, Africa, and South-East Asia Most of the increase in forestation is in Europe and East Asia (China) % managed forested land 90% in Europe 10% in developing countries Forest plantations only cover about 3% of the total forested area, but are growing by almost 3 Mha/year About 30% of all forest land is degraded Deforestation in Malaysia Malaysia is over 58% covered by forest UK – 12% forested Australia – 21% France – 28% USA – 33% Germany – 32% The land area of Malaysia is merely 0.25% of the total land area in the world, but yet this tiny area contains over 10% of the world’s plant species and 7% of the world’s animal species Tropical rainforests like ours contain the largest store of carbon (and nutrients) than other forest types In short, our rainforests are more precious than others Malaysia deforestation statistics (2010) Forest area: 19.324 million ha (58.6% of land area) Mean deforestation rate: 68,400 ha per year Malaysia’s forest area is less than 0.5% of total forest area in the world but we contribute 13% of the world’s deforestation Malaysia’s deforestation rate is also equivalent to the forest size clearing of 11 football (or soccer) fields per hour Malaysia loses about 0.19% of her forest annually Malaysia would be reduced to 50% forest cover by 2057 GHG emissions Agricultural lands and forest represent enormous reservoirs of CO2, in the form of organic matter and wood The amount of carbon stored in forest biomass and soils is larger than what is contained in the atmosphere much of that carbon is underground So GHG emissions are not only determined by activities that generate emissions, but also by the loss or gain in these carbon reservoirs Bert Metz, 2010, Controlling Climate Change, Cambridge University Press, Cambridge Bert Metz, 2010, Controlling Climate Change, Cambridge University Press, Cambridge Bert Metz, 2010, Controlling Climate Change, Cambridge University Press, Cambridge Emissions from agriculture Emissions from agriculture consist predominantly methane (CH4) from animals, manure, and rice production nitrous oxide (N2O) from nitrogen fertilizer application N2O emissions from fertilized soils is the largest source (38%), followed by methane production in animals (32%), burning of crop residues (12%), rice fields (11%), and manure (7%) Although there are large amounts (fluxes) of CO2 going into agricultural crops and soils, there are equally large fluxes going out (digestion and decomposition of agricultural crops and crop residues) thus, the net flux is therefore small Total CH4 and N2O emissions are about 6.2 Gt CO2-eq per year Net CO2 emissions due to the slowly decreasing carbon content of agricultural soils are less than 1% of that amount Magnitude and relative importance of CH4 and N2O depends on regional differences Because of the importance of agriculture in developing countries and the large population, these countries are responsible for about 75% of all emissions in the world Emissions from manure are biggest in developed countries large livestock populations in Latin America, Eastern Europe, and Australia and New Zealand make this the dominant source in those regions Tropical agriculture Trumper, K., Bertzky, M., Dickson, B., van der Heijden, G., Jenkins, M., Manning, P. June 2009. The Natural Fix? The role of ecosystems in climate mitigation. A UNEP rapid response assessment. United Nations Environnent Programme, UNEPWCMC, Cambridge, UK Nitrogen cycle Fluxes (red) are in teragrams (1 Tg = 1012 g = 109 kg = 106 ton = 1 mil. ton) N/year Industrial nitrogen fixation is the production of nitrogen fertilizer from N2 by the chemical Haber-Bosch process. As carbon dioxide rises, food quality will decline without careful nitrogen management by Arnold J. Bloom, California Agriculture 63(2):67-72, 2009 Emissions from forestry Emissions from the forestry sector are predominantly caused by loss from the large carbon reservoirs through deforestation and forest degradation (loss of trees due to selective logging or other disturbance) decomposition of wood residues emissions of CH4 from burning emissions of N2O from fertilized managed forests or forest plantations (about 5.8 Gt CO2/year) dewatering and oxidation or burning of (deforested) peat lands (about 2.7 Gt CO2/year) Trumper, K., Bertzky, M., Dickson, B., van der Heijden, G., Jenkins, M., Manning, P. June 2009. The Natural Fix? The role of ecosystems in climate mitigation. A UNEP rapid response assessment. United Nations Environnent Programme, UNEPWCMC, Cambridge, UK Trumper, K., Bertzky, M., Dickson, B., van der Heijden, G., Jenkins, M., Manning, P. June 2009. The Natural Fix? The role of ecosystems in climate mitigation. A UNEP rapid response assessment. United Nations Environnent Programme, UNEPWCMC, Cambridge, UK Peat lands Peat lands are water logged, high organic soils produced by accumulation of rotting vegetation In many countries a significant part of peatlands has been dewatered and is used for agriculture or forest plantations Agriculture and forestry are responsible for 80% of peat land loss peat harvesting for fuel or soil supplement urbanization infrastructure Dewatered peat land produces CO2 emissions through oxidation of organic material and through fires that keep burning underground largest losses are now happening in Indonesia and Malaysia fires are responsible for about 2 Gt CO2/year Bert Metz, 2010, Controlling Climate Change, Cambridge University Press, Cambridge Trumper, K., Bertzky, M., Dickson, B., van der Heijden, G., Jenkins, M., Manning, P. June 2009. The Natural Fix? The role of ecosystems in climate mitigation. A UNEP rapid response assessment. United Nations Environnent Programme, UNEPWCMC, Cambridge, UK Wood products Wood products are a temporary storage of carbon Wooden houses and other structures and furniture form a carbon reservoir of the order of 5 GtC very small amount compared to what is stored in vegetation and soils Since wood products, including paper, have an average lifetime of about 30 years, the accumulation of carbon in wood products is limited Wood products therefore have a very small contribution to emissions Changes in rainfall pattern from deforestation Deforestation also changes the rainfall pattern with forest, ¼ of rain ends up at rivers or oceans, and ¾ is recycled back into the atmosphere without forest, ¾ of rain ends up at rivers or oceans, and ¼ is recycled back into the atmosphere (the opposite occurs) less recyclable water available, eventually less rain, and less water for humans/animals/plants over-pumping of water from aquifers Summary Increasing population and income (wealth) pushes up the demand for food and meat Increasing oil prices increases the demand for biofuel which competes (and reduces) available food Global grain demand is projected to increase by 75% between 2000 and 2050 and global meat demand is expected to double More than three-quarters of growth in demand in both grains and meat is projected to be in developing countries All these mean greater expansion of agriculture needed to meet those demands But greater expansion of agriculture means greater use of fossil fuels (e.g., electricity, transportation, fertilizers, pesticides, machinery) and more deforestation (opening up of new agricultural lands) Estimated another 400 – 500 Mha additional agricultural land will be needed between today and 2020, even if crop productivity were to improve further Ultimately, more agriculture would lead to greater GHGs emissions and detrimental climate change Total GHG emissions from agriculture and forestry are now about 14.7 Gt CO2-eq/year, approximately 30% of the global total however, this figure is uncertain (could be several Gt higher or lower) because many of the emissions are not easily measured, such as N2O from grasslands, CH4 from rice production or savannah burning, and CO2 from peat land, and forest degradation The emissions from agriculture is expected to go up from the current 6.2 to 8.3 Gt CO2-eq/year by 2030