Download Global change impacts on the Caribbean Food System

Global Environmental
Change Impacts on the
Caribbean Food System
Ulric O’D Trotz, Ph.D
Project Manager
ACCC Project
Working Group I of the IPCC TAR
Concluded
• Global average surface temperature increased by
0.6±0.2°C over 20th Century
• For range of scenarios considered global average
surface temp. projected to warm 1.4-5.8 °C by
2100 relative to 1990
• Global average sea level projected to rise 0.090.88m by 2100
• Changes in climatic variability, and frequency and
intensity of some extreme climate events
Observational evidence indicates that regional
changes in climate (esp. inc. temp.) have already
affected many physical and biological systems
• Shrinkage of glaciers
• Thawing of permafrost
• Later freezing and earlier breakup of ice on rivers
and lakes
• Lengthening of mid to high latitude growing seasons
• Poleward and altitudinal shifts of plant and animal
ranges
• Declines of some plant and animal populations
• Earlier flowering of trees, emergence of insects and,
egg laying in birds
Systems Sensitive to Climate
Change
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Water resources
Agriculture (esp. food security)
Forestry
Coastal zones and marine systems
(fisheries)
• Human settlements, energy and industry
• Insurance and other financial services
• Human health
Projected Adverse Impacts
• General reduction in crop yields in most tropical
and subtropical regions for most projected
increase in temperature
• General reduction, with some variation, in
potential crop yields in most regions in midlatitudes for increase in annual average
temperature
• Reduced water availability in most water scarce
regions
• Widespread increase in risk of flooding from
increased heavy precipitation events and sea level
rise
Projected Beneficial Impacts
• Increased potential crop yields in some regions at
mid-latitudes for increase in temperature
• Potential increase in global timber supply for
appropriately managed forests
• Increased water availability for populations in
some water scarce regions
Agriculture and Food Security
• Crop yield responses to climate change varies, and
depends on:
– Species and cultivar
– Soil properties
– Pests and pathogens
– Interactions between C02, air temperature,
water stress, mineral nutrition, air quality and
adaptive responses
Temperature
• In tropics, some crops near their max. temperature
tolerance yields expected to decrease with even
minimal changes in temperature. If coupled with
large reductions in rainfall, crop precipitation
yields even more adversely affected.
• Few degrees projected warming will lead to
general increase in temperate crop yields. larger
amounts of warming will lead to a reduction.
• Higher minimal temperatures – beneficial to some
crops, especially in temperature regions –
detrimental to numerous crops
Temperature
• In the absence of climate change most
studies predict declining real prices for
agricultural commodities
• Impacts of climate change on agriculture
estimated to result in small percentage
changes in global income – positive in
developed regions, and smaller or negative
in developing world
Temperature
• Mean annual temperature increase of 2.5°C or
greater, prompt food prices to increase as a result
of slowing expansion of global food capacity
relative to growth in global food demand.
• At lesser amounts of warming, global impact
assessment models cannot distinguish climate
signal from other sources of change
• Recent aggregated studies estimated economic
impacts on small holder producers and poor urban
consumers, indicate that climate change will lower
incomes of vulnerable populations and increase
number of people at risk to hunger.
Temperature
• Increases in extreme events likely to
increase heat stress-related livestock deaths
• Winter warming may reduce neonatal
deaths at temperate latitudes
Degradation of Soil and Water
Resources – one of the major challenges
for global agriculture
• Established that these processes likely to be
intensified by adverse change in temperature and
precipitation
• Land use and management has greater impact on
soil conditions than indirect effect of climate
change
• Opportunity to mitigate the latter
• Research on direct effects of CO2 on crops suggest
that beneficial effects may be greater under certain
stressful conditions including warmer temperature
and drought
• Effects established for a few crops under
experimental conditions – yet to be validated in
‘on-farm’ conditions
• Numerical estimates of climate change impacts on
production, income, prices obtained from
aggregated integrated assessment models
• Confidence in outputs low due to
uncertainties in:
– Magnitude and persistence of rising CO2 on
crop yield under realistic farming conditions
– Potential changes in crop and animal pest losses
– Spatial variability in crop responses to climate
change
– Effects of changes in climate variability and
extreme events on crops and livestock
Sea Level Rise, Sea Surface
Temperature
• Salt water intrusion into estuaries
• Salinization of aquifers and agricultural
soil
• Inundation
• Impacts on marine ecosystems – reefs (sea
water temp), sea grass beds, mangroves
Fisheries
• Habitat degradation – mangroves, reefs, sea grass
beds
• Profound impact on biological production of
oceans including fish production changes in
upwelling rates would have major impact on
coastal fish production
• Increase in frequency of El Niño events will lead
to decline of plankton biomass and fish larvae
abundance – adverse effect on fish and ocean
biodiversity
Fisheries
• Fluctuations in fish abundance are
increasingly regarded as
– Biological responses to medium term climate
fluctuations in addition to
• Overfishing
• Other anthropogenic factors
Fisheries
• Growing recognition of the role of the climateocean system in management of fish stocks
leading to new adaptive strategies based on
determination of acceptable removable
percentages of fish stock resilience.
• Adaptation by expansion of marine aquaculture –
in 1997 accounted for about 30% total commercial
fish and shell production.
Some Regional Projections
• Africa
– Vulnerability high as a result of heavy dependence
on rain-fed agriculture, frequent droughts and
floods
– Grain yields projected to decrease diminishing
food security, particularly in small food-importing
countries
– Increased droughts, floods and other extreme
events add stress to food security
– Significant extinctions of plant and animal species
projected and would impact rural livelihoods
• Asia
– Decreases in agricultural productivity and
aquaculture
– Diminished food security in many
countries of arid, tropical and temperate
Asia
– Expanded agriculture and increased
productivity in Northern areas
• Australia / New Zealand
– Net impact on some temperate crops of
climate and CO2 changes may initially be
beneficial, but balance is expected to
become negative for some areas and
crops with further climate change.
– Water stress in some regions due to
change to a more El Niño-like average
state
• Europe
– Broadly positive effects on agriculture in
Northern Europe; decrease in
productivity in Southern and Eastern
Europe
– Negative impacts on average due to
increased river flood hazard, erosion and
wetland loss
• Latin America
– Yields of important crops projected to
decrease even when effects of CO2 taken
into account
– High threat to subsistence farming
• North America
– Some crops would benefit from modest
warming accompanied by increased O2 but
effects would vary among crops and regions
– Declines due to drought in some areas of
Canadian Prairies and US. Great Plains
– Potential increased food production in areas of
Canada, North of current production areas
– Benefits for crops would decline at an
increasing rate and become net loss with further
warming