Climate change

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Climate change

• Impacts and Strategies

Roberto Ferrise, Giacomo Trombi, Marco Moriondo
Marco Bindi DiSAT University of Florence IFAD,
Rome IFAD July, 24th 2008
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Facing with Unprecedented Conditions
Temperature and CO2
World population
6.7 Billions
High Temp. and CO2
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Future Climate Projections
Extreme Events
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Extreme events impact on subsistence farming

• In the short/medium term (to 2025), rural poor
  communities will be more strongly affected by the
  impact of extreme events than the impacts of
  changing means (Corbera et al.)
• Expected impacts on farming systems include
• Damage to crops at particular developmental
  stages
• More difficult timing of agricultural operations
• Damage to infrastructure
• Reduced incentive to cultivate

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Agro-ecosystem sensitivity to climate now

• General Constraints
• Incoming solar radiation
• Temperature
• Water and nutrient availability
• Effect on agricultural crops
• Incoming solar radiation regulates photosynthesis
  processes
• Air temperature controls the duration of the
  growing period and other processes linked with
  the accumulation of dry matter (i.e. leaf area
  expansion, respiration)
• Rainfall and soil water availability affects the
  duration of growth (i.e leaf area duration and
  photosynthetic efficiency)
• Effect on animals (behaviour and production)
• metabolic processes (direct effect)
• forage quality and quantity (indirect effect)

• Local Constraints
• Heat stresses
• Hails and storms
• Floods

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Agro-ecosystem sensitivity to Climate Change in
the future
Climate change is expected to affect the
agricultural production acting on the main
processes that regulate the different components
of the agro-ecosystem
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1. Plants (I)

• Enhanced CO2
• Yield quantity Plants will be directly
  stimulated by enhanced concentrations of CO2
  leading
• to larger and more vigorous plants
• to higher yields of total dry matter (roots,
  shoots, leaves) and harvestable product

for a doubling CO2 Source Kindball, 1983
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Plants (II)

• Changes of climatic parameters
• Temperature. Higher temperature will lead
• yields reduction of determinate crops, i.e.
  cereals (shorter growing season)
• yield increase in indeterminate crops, i.e.
  forage crops (longer growing season)
• Rainfall. Lower rainfall in summer season will
  lead
• water shortage that may be harmful especially for
  crops like wheat, sunflower, soybean

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Combined effect of CC and enhanced CO2 on crop
production

• Yields of C3 crops (vegetable, wheat and
  grapevine) generally increase
• Yields of C4 crops and summer crops generally
  decrease
• Inter-annual variability of crop yields increase
• Yield quality may be affected

UKTR model, decade 66-75, CO2 617 (Source
Harrison and Butterfield, 1995)
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2. Water availability

• Demand for water for irrigation will rise
  increasing the competition between agriculture
  and urban as well as industrial users of water
• Water tables will fall making the practice of
  irrigation more expensive
• Peak irrigation demands will rise due to more
  severe heat waves
• Risk of soils salinisation will be increase for
  higher evaporation

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3. Soil fertility and erosion

• Higher air temperatures
• speed up the natural decomposition of soil
  organic matter increasing the rates of other soil
  processes (loss of fertility).
• accelerate the cycling of carbon, nitrogen,
  phosphorus, potassium and sulphur, in the
  soil-plant-atmosphere system (enhancement of CO2
  and N2O greenhouse gas emissions).
• increase the process of nitrogen fixation due to
  greater root development
• Changes in rainfall
• increase the vulnerability to wind erosion
  suppressing both root growth and decomposition of
  organic matter (lower summer precipitations)
• increase soil erosion favouring run-off (higher
  frequency of high intensity precipitation events)

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4. Pests and Diseases

• Depending on the specific interaction between
  pests/diseases/weeds, and crops and climate there
  may be either an increase, a decrease or no
  change in their effects on agricultural crops.
• e.g. Maize Streak Virus and Cassava Mosaic Virus
  in areas where rainfall decreases, and sorghum
  headsmut (a fungal disease) in areas where
  rainfall decreases.
• Main drivers
• higher temperature may be more favourable for the
  proliferation of insect pests (longer growing
  seasons, higher possibility to survive during
  winter time)
• enhanced CO2 may affect insect pests through
  amount and quality of the host biomass (higher
  consumption rate of insect herbivores due to
  reduced leaf N)
• altered wind patterns may change the spread of
  both wind-borne pests and of bacteria and fungi
• increased frequency of floods may increase
  outbreaks of epizootic diseases (i.e. African
  Horse Sickness)

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5. Weeds

• The differential effects of CO2 and climate
  changes on crops and weeds will alter the
  weed-crop competitive interactions
• higher CO2 concentration will stimulate
  photosynthesis in C3 species and increase water
  use efficiency in both C3 and C4 species
• changes in temperature, precipitation, wind and
  air humidity may affect the effectiveness of
  herbicides

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Prospected agro-ecosystem response to CC
The response of agricultural production will be
extremely variegated and very crop and site
dependent Crop productivity is projected to
increase slightly at mid- to high latitudes for
local mean temperature increases of up to
1-3C depending on the crop, and then decrease
beyond that in some regions. At lower
latitudes, especially seasonally dry and
tropical regions, crop productivity is projected
to decrease for even small local temperature
increases (1-2C), which would increase the risk
of hunger.
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Prospected agro-ecosystem response to CC
Increases in the frequency of droughts and floods
are projected to affect local crop production
negatively, especially in subsistence sectors at
low latitudes. Following climate change, crops
are likely to shift their cultivation area to
meet their specific optimum climate conditions.
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a. Cereals and seed crops

• The cultivation area will shift toward higher
  latitudes or altitudes
• Drier conditions may lead to lower yields
• Warmer temperatures will shorten the length of
  growing season and reduce yields
• Such an effect will be partially counteracted by
  the increase in CO2 concentration, which also
  will lead to increased symbiotic nitrogen
  fixation in pulses

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b. Root and tuber crops

• Due to their large below ground sinks for carbon
  are expected to show large response to rising CO2
• Warming may reduce the growing season in some
  species (potato) and increase water requirements
  with consequences for yields
• Other species (sugar beet) will benefit from both
  warming and the increase in CO2 concentrations

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c. Pasture

• Yield is strictly dependent on the projected
  rainfall pattern
• Primary production may increase in temperate
  regions but decrease in semiarid and tropical
  regions
• Species distribution and litter composition will
  change (high CO2 levels may favor C3 plants over
  C4 the opposite is expected under associated
  temperature increases)
• Yields will differently affected by weeds, pests,
  nutrient, competition for resources.

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Prospected impact on livestock systems

• Climate change may influence livestock systems
  through different pathways
• Changes in availability and prices of grains for
  feeding (cereals, pulses and other feed grains)
• Changes in productivity of pastures and forage
  crops
• Change in distribution of livestock diseases
• Changes in animal health, growth, and
  reproduction (direct effects of weather and
  extreme events)
• Climate change may also affect the turn-over and
  losses of nutrients from animal manure, both in
  houses, storages and in the field influencing the
  availability of manure in organic farms

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Vulnerable areas a focus on developing countries

• Developing countries will bear the brunt of
  climate change impacts.
• Smallholder and subsistence agriculture are
  particularly vulnerable, but to understand the
  impact of CC on them it is necessary to
• Recognize the complexity and high
  location-specificity of their production systems
• Take into account non-climate stressors on rural
  livelihoods.
• Consider the multiple-dimensions impact of
  climate change on rural farming systems and
  livelihoods.

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Vulnerable areasLATIN AMERICA (I)

• Significant loss of biodiversity (through
  species extinctions in many areas of tropical
  Latin America)
• Reduction of tropical forest due to
• Replacement by savannah (eastern Amazonas,
  central and South Mexico)
• Increased susceptibility to fire occurrences
• Land-use change (deforestation, agriculture
  expansion, financing large scale project such as
  dams, roads, etc)
• Agricultural lands are very likely to be
  subjected to desertification and salinisation
• Changes in precipitation patterns are projected
  to affect water availability for human
  consumption, agriculture and energy generation

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Vulnerable areasLATIN AMERICA (II)
Great variability of yield projections (-30
Mexico to 5 in Argentina) Rice yields is
expected to decrease after the year 2010
Soybean will increase yields when CO2 effects
are considered A mean reduction of 10 in maize
yields could be expected by 2055 Land suitable
for growing coffee in Brazil and Mexico is
expected to be reduced Heat stress and more dry
soils may reduce yields to 1/3 in the tropics
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Vulnerable areas ASIA
A northward shift of agricultural zones is likely
(Tserendash et al., 2005). Rice, maize and wheat
production will decline due to the increased
water stress, arising from increasing temperature
and reduction of rainy days   Yield of rice is
expected to decrease by 10 for every 1C
increase in growing season minimum temperature
(Peng et al., 2004) Aridity in Central and West
Asia may reduce growth of grasslands and
increases bareness of the ground surface
(Bou-Zeid and El-Fadel, 2002) Agricultural
irrigation demand in arid and semi-arid regions
of Asia is estimated to increase by at least 10
for an increase in temperature of 1C (Fischer et
al., 2002 Liu, 2002).
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Vulnerable areas AFRICA

• Africa is probably the most vulnerable continent
  to climate change and climate variability.
• CC will cause some countries to become at risk of
  water stress exacerbating current water
  availability problems
• CC will be likely to reduce the length of growing
  season as well as force large regions of marginal
  agriculture out of production.
• Thus, agricultural production and food security
  (including access to food) are likely to be
  severely compromised
• Hotspots for vulnerability in Africa are
  semiarid mixed rain-fed crop-livestock systems in
  the Sahel, arid and semiarid grazing systems in
  East Africa and mixed crop-livestock and highland
  perennial crop systems in the Great Lakes Region.
  (ILRI, 2006)

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CC impact on smallholder and subsistence
agriculture

• Negative impact on food and cash crops, due to
  the increased likelihood of crop failure
• Impact on productivity and health of livestock,
  due to increased diseases and mortality of
  livestock and/or forced sales of livestock
• Livelihood impacts including sale of other
  assets, indebtedness, out-migration, etc.
• Increased water stress
• Exacerbation of existing environmental problems
• Non-agricultural impacts (human health, ability
  to provide labor for agriculture, tourism, etc.)

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How to cope with Climate Change

• Mitigation strategies of climate change (action
  on the causes)
• Adaptation strategies to climate change
  (alleviate the effects)

Tubiello, 2007
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Mitigation
denotes reduced emissions or enhanced removal
(positive mitigative effect)
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Main adaptive strategies

• Economic and agronomic adaptation strategies will
  be important to limit losses and exploit possible
  positive effects
• The economic strategies are intended to render
  the agricultural costs of climate change small by
  comparison with the overall expansion of
  agricultural products
• The agronomic strategies intend to offset either
  partially or completely the loss of productivity
  caused by climate change
• Agronomic strategies
• short-term adjustment
• long-term adaptation

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Main adaptive strategies Short Term (I)

• Short-term adjustments may be considered as the
  first defence tools against climate change and
  aims to optimise production with minor system
  changes through
• The management of cropping systems
• The conservation of soil moisture

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Main adaptive strategies Short Term (II)

• The management of cropping systems considers
• Changes in crop varieties (varieties with
  different thermal requirements, varieties given
  less variable yields)
• Introduction of grater diversity of cultivars
• Changes in agronomic practices (sowing/planting
  dates)
• Changes in fertiliser and pesticide use
• The conservation of soil moisture considers
• The introduction of moisture conserving tillage
  methods (minimum tillage, conservation tillage,
  stubble mulching, etc.)
• The management of irrigation (amount and
  efficiency)

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Main adaptive strategies Long Term (I)

• Long-term adaptation may overcome adversity
  caused by climate change through major structural
  system changes
• Changes in land allocation to optimise or
  stabilise production (e.g. substituting crops
  with high inter-annual variability in production
  (wheat) with crops with lower productivity but
  more stable yields (pasture))
• Development of designer-cultivars to adapt to
  climate change stresses (heat, water, pest and
  disease, etc.) much more rapidly than it possibly
  today
• Crop substitution to conserve of soil moisture.
  (e.g. sorghum is more tolerant of hot and dry
  conditions than maize)

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Main adaptive strategies Long Term (II)

• Microclimate modification to improve water use
  efficiency in agriculture (e.g. windbreaks,
  inter-cropping, multi-cropping techniques)
• Changes in nutrient management to reflect the
  modified growth and yield of crops, and also
  changes in the turn-over of nutrients in soils,
  including losses.
• Changes in farming systems to maintain farms
  viable and competitive (e.g. conversion of
  specialised farms in mixed farms less sensitive
  to change in the environment)

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Main adaptive strategies Spatial scale
classification

• Farm level
• Risk amelioration approaches (minimum disturbing
  techniques, planting times and density, etc)
• More opportunistic crops (environment, climate,
  market)
• Varieties with appropriate thermal time and
  vernalisation requirements, resistance to new
  pests, etc
• Regional level
• Integrate climate change in regional planning
  (avoid stresses for the environment caused by
  inappropriate actions)
• National level
• Building resilient agricultural systems, able to
  cope with CC
• (transition, communication, diversifying,
  training, water, etc)

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Coping with climate change in poor rural farming
systems

• Small farm sizes, low technology, low
  capitalization and diverse non-climate stressor
  will tend to increase the vulnerability of poor
  rural farmers.
• Smallholder and subsistence agriculture systems
  are already characterized by constant adaptation
  to climate variability, which is forming the
  basis of adaptation to climate change.
• Typical resilience factors such as family labor,
  existing patterns of diversification away from
  agriculture and indigenous knowledge should not
  be underestimated as important elements of
  adaptation strategies.

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Main implications for related sectors (I)
Food sector
Changes in diet patterns (e.g. food calorie
intake in China India)
Increased Population
Reduced water availability
Food production
Increased water need for industry households
Higher/Wider production needed
Increased water need for irrigation
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Main implications for related sectors (II)
Forestry may be affected by drier and warmer
conditions in the Mediterranean region that could
lead to more favourable conditions for
agro-forestry Water resources may be interested
by warmer and drier conditions during summer that
will enhance the demand for freshwater,
especially for agriculture and human
consumption Insurance my be affected by an
altered frequency of extreme weather events
(e.g. storms, hails or floods) that will lead to
lower or higher damage costs Other sectors that
will contribute to rural income (e.g. ecotourism,
nature management, culture) may be affected
directly or indirectly by climate change.
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Main uncertainties

• Those related to the possibility to include in
  the assessments all the sources of uncertainties
  (e.g. climate scenario, crop experiments, models
  and spatialisation procedures)
• Those linked with unpredictable directions of
  future social, economic, political and technical
  changes (e.g. questions regarding population and
  technological change are particularly relevant
  and should be explored with upper and lower
  bounds of possible projections)

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Main unknowns (I)

• The impact of climate change on secondary factors
  of agricultural production like soil, weeds,
  pests and diseases
• The impact of increased surface receipts of UV-B
  radiation on future agricultural performance and
  agricultural response to climate change.
• The response of the quality of agricultural
  products to atmospheric CO2 concentration
  increases, climate change and exposure to
  atmospheric pollutants

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Main unknowns (II)

• The impact of changes in mean climate and climate
  variability on mean yield and yield variability
• The impact of increasing isolated and extreme
  events (e.g. hail, strong winds, flooding and
  extreme high temperatures) on agricultural
  production
• The response of crop production and farming
  systems in sensitive or vulnerable regions (e.g.
  Asian and African countries on the Mediterranean
  shore)

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Recommendations (I)

• Encourage flexible land use (Resource land).
• Encourage more prudent use of water (Resource
  water)
• Improve the efficiency in food production and
  exploring new biological fuels and ways to store
  more carbon in trees and soils (Resource energy)
• Assemble, preserve and characterise plant and
  animal genes and research on alternative crops
  and animals (Resource genetic diversity)

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Recommendations (II)

• Encourage research on adaptation, developing new
  farming systems and developing alternative foods
  (Resource research capacity)
• Enhance national systems that disseminate
  information on agricultural research and
  technology, and encourages information exchange
  among farmers (Resource information systems)
• Promote the development of agricultural weather
  information systems including the use of
  long-term weather forecasts (Resource
  management).
• Integrate environmental, agricultural and
  cultural policies to preserve the heritage of
  rural environments (Resource culture).