Land Use Emissions, Rice

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Land Use Emissions, Rice
Climate Change

• Yaqiu Li
• Jiangfeng Wei
• Yan Zhang
• Wenyan Yu

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Outline

• Land-use emissions
• Rice and methane
• Climate change effects on rice

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Land useThe total of arrangements,
activities, and inputs that people undertake in a
certain land cover type.

• Peri-Urban Land
• Wetlands
• Cropland
• Agroforestry Land
• Rangeland/Grasslands
• Forest Land
• Deserts

In sequence of increasing intensity of use,
basically
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The Influence of Land Use on Greenhouse Gas
Sources and Sinks

• Land-use emissions
• Carbon stocks
• Land-Use Management

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land-use main emissions

• CO2 from net deforestation (nearly all)
• CH4 from rice cultivation
• CH4 from enteric fermentation of cattle
• N2O from fertilizer application (80)

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Emissions of carbon dioxide due to changes in
land use mainly come from the cutting down of
forests
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Source of CH4
CH4 Source Mt CH4 yr-1 Gt C-eq yr-1
Livestock 110 (85130) 0.6 (0.50.7)
Rice paddies 60 (20100) 0.3 (0.10.6)
Biomass burning 40 (2080) 0.2 (0.10.5)
Natural wetlands 115 (55150) 0.7 (0.30.9)
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N2O Source
N2O Source Mt N2O yr-1 Gt C-eq yr-1
Cultivated soils 3.5 (1.85.3) 0.9 (0.51.4)
Biomass burning 0.5 (0.21) 0.1 (0.050.3)
Livestock (cattle and feed lots) 0.4 (0.20.5) 0.1 (0.050.13)
Natural tropical soilswet forests 3 (2.23.7) 0.8 (0.61)
Natural tropical soilsdry savannas 1 (0.52) 0.3 (0.10.5)
Natural temperate soilsforests 1 (0.12) 0.3 (0.030.5)
Natural temperate soilsgrasslands 1 (0.52) 0.3 (0.10.5)
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Carbon Stocks

• Land-use change is often associated with a change
  in carbon stocks.
• conversion of natural ecosystems to permanent
  croplands,
• conversion of natural ecosystems for shifting of
  cultivation,
• conversion of natural ecosystems to pasture
• abandonment of croplands,
• abandonment of pastures,
• harvest of timber,
• establishment of tree plantations

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Global carbon stocks in vegetation and top 1 m of
soils

Area(106 km2) Area(106 km2) Carbon Stocks (Gt C) Carbon Stocks (Gt C) Carbon Stocks (Gt C)
Biome Area(106 km2) Area(106 km2) Vegetation Soils Total

Tropical forests Tropical forests 17.6 212 216 428
Temperate forests Temperate forests 10.4 59 100 159
Boreal forests Boreal forests 13.7 88 471 559
Tropical savannas Tropical savannas 22.5 66 264 330
Temperate grasslands Temperate grasslands 12.5 9 295 304
Deserts and semideserts Deserts and semideserts 45.5 8 191 199
Tundra Tundra 9.5 6 121 127
Wetlands Wetlands 3.5 15 225 240
Croplands Croplands 16.0 3 128 131

Total 151.2 151.2 466 2011 2477

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Land use managent

• Vegetation can sequester or remove carbon
  dioxide from the atmosphere and store it for
  potentially long periods in above- and
  below-ground biomass, as well as in soils.
• Soils, trees, crops, and other plants may make
  significant contributions to reducing net
  greenhouse gas emissions by serving as carbon
  sinks.

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Options for Managing Terrestrial Carbon

• Avoid emissions through the conservation of
  existing carbon stocks in forests and
  otherecosystems, including in soils (i.e.,
  reducing LULUCF emissions). An example is
  reducing the rate of deforestation.
• Sequester additional carbon in forests and
  other ecosystems (including in soils), in forest
  products, and in landfills (i.e., enhancing
  LULUCF removals). An example is planting trees
  where there have not been trees in the past
  (afforestation).

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Options for Managing Terrestrial Carbon

• Substitute renewable biomass fuels for fossil
  fuels (i.e., fuel substitution), or use biomass
  products to replace products from other materials
  such as steel or concrete, that have different,
  often greater, fossil-fuel requirements in their
  production and use (i.e., materials
  substitution).

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Mean annual carbon emissions from alternative
land-use management options (1991-2001).
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Methane and Rice

• 1. Methane (CH4) is second important greenhouse
  gas (GHG).
• 2. In 100 year period, a molecular CH4 can absorb
  about 25 times more energy than a molecular CO2.

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Methane emission from rice fields
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Global estimates of CH4 emission from rice fields

• 1. The source strength of rice fields in Asia was
  estimated to range between 46 and 63 million t/yr
  of methane.
• 2. Comprising 51 of the global harvested rice
  area, rice fields in China and India emit 29-40
  million t/yr.
• 3. Global estimates of rice field methane
  production range up to 100 million t/yr.

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Different emission in Asia

• Irrigated rice, comprised 50 of total rice
  area, accounts for 80 of methane emissions.

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Emissions vary in different locations
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Sinks

• 1. Troposphere stratosphere
• broken down by OH
• Troposphere 506 Tg/yr
• Stratosphere 40 Tg/Yr

• 2. Soil
• about 30 Tg/yr

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Mitigation of effect

• Emission reductions produce an immediate and
  significant impact on climate change
• Why?

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Rice Paddies and methyl halides

• Figure 1. Maxwell, California, averaged weekly
  fluxes during 1998 for methane, methyl chloride,
  methyl bromide, and methyl iodide. Arrows
  indicate maximum tillering (M, 55 DAS), booting
  (B, 70 DAS), heading (H, 80 DAS), flowering (F,
  90 DAS), and the reflooding date (RF, 45 DAS).
  The flux for all gases is shown note differing
  scales of emission for each gas. Symbols ,
  straw-incorporated plots , burnt straw plots
  , controls. Error bars show one standard
  deviation.

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• Fig. 2. Maxwell, California, averaged weekly
  fluxes during 1999 for methane, methyl chloride,
  methyl bromide, and methyl iodide. Arrows
  indicate maximum tillering (M, 47 DAS), booting
  (B, 75 DAS), heading (H, 89 DAS), and flowering
  (F, 97 DAS). The flux for all gases is shown
  note differing scales of emission for each gas.
  Symbols , straw-incorporated plots , burnt
  straw plots , controls. Error bars show one
  standard deviation

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The worldwide rice farming contributes

• methyl bromide -----1
• methyl iodide -------5

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Impacts of Global Climate Change on Rice
Production
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• ----What the rice paddies looks like from the
  sky?
• ----People working in the rice paddies.

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The Importance of Rice

• One of the worlds most important food crops,
  staple food for over 50 people in this world.
• To meet the demands of a growing population,
  agricultural productivity must continue to
  increase.
• If global climate changes act to reduce food
  production, serious, long-term food shortages and
  aggravation of societal problems could result.

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Climate Reasons that affect the Rice
Growing

• 1. Greenhouse Gases and Increased temperature
• Concentrations of GHGs like CO2 and CH4 have
  increased significantly since preindustrial
  times. The concentrations of these gases have a
  powerful influence on the average global
  temperature of the planet, and consequently,
• on the global climate.

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2. Stratospheric Ozone Depletion Effects on
Rice---UV-B Radiation

• . Rice is the worlds most important food crop
  and grown mostly in tropical and subtropical
  countries.
• . It is know that UV-B radiation is highest in
  tropical regions where rice is grown, because the
  stratospheric ozone layer is high latitude, and
  the solar angles are higher.
• . After preindustrial period, people have
  release great amount of ozone decomposing
  matters, like chorofluorocarbons (CFCs) which
  already induced stratospheric ozone depletion,
  thus increasing the incoming UV-B.

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Climate Change Rice Response to UV-B
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Biogeochem Circling
Biodiversity
Yield
Endpoints
Competition
pest, Pathogen, Decomposition
Ecosystem
Growth,Yield Morphology, Chemical matters
Whole Plant
Photosynthesis Carbon Allocation
Tissue
Targets
Molecular
UV-B
known less known
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Effect of UV-B on Rice Yield
Cultivar Lebonnet
Seed dry weight (g)
0 16
23 32
Percent UV-B Enhancement
1.Possible trends towards a reduction in
seed yield under enhanced UV-B conditions of
ozone depletions of 8 to 16
(Florida, US, 1984)
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2. Rice growth and photosynthesis can be
suppressed by exposure to UV-B under greenhouse
conditions. 3. UV-B can induce the accumulation
of UV-absorbing pigments and alter leaf surface
characteristics. But, it is unknown
whether these responses are sufficient to
completely protect rice from increased exposure
to UV-B. 4. UV-B can alter plant morphology
without reducing plant biomass. These
morphological traits, like tillering, is known to
influence rice yield, UV-B could potentially
alter grain yield without apparent reductions in
total production
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5. UV-B radiation changing rice productivity
related to radiation magnitude and direction. And
this character depends on rice cultivar. 6.
Results from pilot experiments indicate that UV-B
enhancement can significantly increase the
susceptibility of rice to blast disease. 7. UV-B
enhancement is known to alter the competitive
balance between crops and weeds
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Global warming Effects of CO2 and
temperature on rice production
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Effects of CO2 and temperature on the rice
ecosystem

• Increasing atmospheric CO2 stimulates plant
  growth, the beneficial effects on rice growth
  have been observed for levels only up to 500 ppm.
  Some plant species respond positively to CO2
  levels up to 1,000 ppm.
• The benefits of increased CO2 would be lost if
  temperatures also rise. That is because increased
  temperature shortens the period over which rice
  grows.

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Interactive effects of CO2 and temperature
8000
7000
6000
5000
yield (kg/ha)
4000
3000
2000
1000
0
CO
(ppm)
2
Temperature change (K)
(Bachelet et al., 1993)
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Indirect effects of global climate change on rice

• Altered timing and magnitude of precipitation
  can induce drought or flood injury
• Increased temperatures, and/or changes in
  precipitation could have dramatic impacts on rice
  diseases and insects.
• Enhanced UV-B, enriched CO2 and increased
  temperatures may all alter competition between
  rice and major weeds, and the contribution of
  other organisms to nitrogen fixation in rice
  fields.

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Models
Both models (ORYZA1, SIMRIW) were potential
production models i.e. yield determined only by
temperature, sunlight, CO2 level, daylength, crop
variety, planting and harvest dates Did not take
into account water limitations nutrient (N,P,K)
limitations weeds, pests diseases
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Climate scenarios
General Circulation Models (GCMs)


GFDL

GISS

UKMO


Name

Geophysical
Goddard
United
Fluid
Institute of
Kingdom
Dynamics
Space Studies

Meteorological
Laboratory

Office


Base CO
(ppm)

300

300

323

2

Temperature
4.0

4.2

5.2



change (
C)


Precipitation
8

11

15

change ()




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Predicted yield changes
3 GCM scenarios
change in regional rice production
predicted by ORYZA1 and SIMRIW under
different GCM scenarios
GFDL
GISS
UKMO
ORYZA1
6.5
-4.4
-5.6
68 weather stations
SIMRIW
4.2
-10.4
-12.8
(Matthews et al., 1995)
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Model results

• The results of recent international modeling
  exercises suggest a mixed future of 2XCO2 for
  rice production in Asia, with some countries
  benefiting and others losing production.
• Overall, Asian rice production, based on present
  varieties and systems, could decline by about 4
  in the climates of the next century.

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ENSO and rice production (Sri Lanka)
October to May
May to September
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Adaptation options

• Adjusting planting dates to avoid higher
  temperatures at flowering time (warmer regions)
• Breeding temperature tolerant varieties (warmer
  regions)
• Transition from single-cropping to
  double-cropping where extended growing season
  permits (cooler regions)
• Selection for varieties with greater response to
  elevated CO2 (all regions)
• Breed crop plants tolerant to UV-B radiation

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Conclusion

• Land use change has an influence on green house
  gas sources and sinks.
• Rice paddies are a large source of CH4, an
  assessment of the agricultural effects of global
  environmental change must include rice as a crop
  of primary interest.
• While there is some information regarding the
  single effects of UV-B, CO2, temperature and
  precipitation on rice, little is know about the
  interactive effects of these factors.