// lecture 31 Flashcards
Duck Hunting and Climate Change
on the central flyway: there is the prairie potholes region. contains millions of shallow depressions that fill with water in spring and these ponds provide a breeding habitat for millions of ducks and other migratory birds and many species of resident wildlife. as climate warms, many ponds could dry up or be wet for shorter periods, making them less suitable for breeding. P is greater than E.
Prairie Potholes
is also on top of geological formations underneath that have petroleum. unique grasslands. lots of oil development.
threats to biodiversity for 2100
land use #1 threat, global warming #2, but this varies by region.
CO2 Increase: good or bad for plants
- CO2 warms the climate creating greater water demand: plants need water for photosynthesis and plants use water for cooling in hot weather
- CO2 is necessary for plants to grow through photosynthesis: CO2 fertilization (faster growth with more CO2) and plants also limited by nutrients (fixed nitrogen).
- so overall, is it good or bad?
Leaves, Stomata, and Photosynthesis
- leaves have pores called stomata which open during photosynthesis.
- CO2 goes in, O2 and H20 come out
- you might think that plants would grow faster or survive with less water, if more CO2 is in the air.
- some evidence trees grow faster with more CO2 - evidence of crop enhancements is less evident
- jury still out on balance of CO2 fertilization versus heat and water stress effect
More CO2 in the atmosphere can help plants
- more abundant so chemistry works better
- need to leave stomata open for less time, so more photosynthesis per unit of transpiration
- transpiration is the loss of water through leave stomata
but many plants are limited by other constraints
- nutrients in soil
- sunlight
- soil water
- temperature – too high or too low not good - plants also cool by transpiring water through their stomata (a small ~5% of the water they consume is used for photosynthesis, the rest is transpired unused except for cooling)
where does the food insecure live?
- 800 M people are malnourished today
- 95% are in the tropics/subtropics
- the food secure are also the poor. they depend heavily on agriculture for both food and income
2012 study on food security
15% of people are chronically undernourished, down from 23%. mostly in SE asia and and sub-saharan (South) africa.
as societies get richer
their diet diversifies
what do the food insecure eat
- rice (26%)
- wheat (17%)
- sugar cane (8%)
- maize (6%)
- nuts (5%)
- cassava (yuca) (4%)
- other (34%)
top producers of rice
china, india, indonesia, bangladesh, vietnam
top producers of wheat
china, india, usa, russia, france
top producers of maize
usa, china, brazil, mexico, argentina
top producers of cassava (yuca)
nigeria, brazil, thailand, indonesia, congo
food facts
- avg total daily calorie consumption: 2700
- total calories: 84% from plants (54% from cereals; rice and wheat are nearly 50%…), 16% from animals, and 1% from fish
- 40% of food comes from 17% of cropland that’s irrigated
the green revolution
- increase in global food production, esp in developing world, allowed the world population to double between 1960 - 2000.
- new strains of crops that produce more food per acre
- application of fertilizer
- application of water with irrigation
- application of pesticides
- application of non-animal energy such as tractors
world population
- has increased exponentially - faster and faster
- population increase ~ population x fertility
green revolution problems
- supply of water is reaching limits
- soil is overworked or salting up
- pesticides accumulate
- financing of fertilizer and equipment is becoming an issue
- pesticides accumulate
the 1998 - 2001 drought in the middle east
- iran: 80% of livestock lost, 35-75% reduction in wheat and barley
- afganistan: 40% of livestock lost
- pakistan: 50% of livestock lost
- tajikistan: 50% of grain crop lost
by 2100 similar water stress on agriculture will likely be the norm in soe locations in the tropics and subtropics due to GW. hard to know exactly where though
facts about indonesia
- about 240 M people (fourth in the world)
- 50% of the population in agriculture; 17% in poverty
- rice is the staple crop here: two crops per year, depending on rainfall and mostly irrigated by run of the river
main problem in indonesia today: late onset of the monsoon season
- delays the first planting (lengthens the hungry season)
- less overall planting
- el nino greatly affects annual rice production by delaying monsoon onset
- the typical el nino event delays onset by ~30 days
- reduces total annual rice production by a total of 1 million metric tonnes (enough to feed 15 M ppl a year)
- impact is non-linear (threshold)
- increases domestic and traded rice prices
- forecats of rice production based on ele nino supplied by Battisti’s tream since 2001: they make decisions like whether to start importing more based on this and building long-term relationships key
projecting rainfall in Java/Bali in 2050
- use the output from climate models with two emissions scenarios: A2 with relatively high greenhouse gas emissions and B1 with low emissions, sustainable development
- build empirical models to downscale and debias precipitation from climate models
- provides full range of projections to span the space of uncertainty
findings: Java/Bali in 2050
- the monsoon rains will start 1-2 weeks later
- rainfall will increase during the monsoon season
- the monsoon will end abruptly and the dry season will be drier
- net impact: by 2050, the second season rice crop is marginal (too short for two crops) and highly vulnerable
adaption: ways of planning for this
- methods for water storage and water management
- crop breeding for drought tolerance
- crop diversification
- early warning systems
Extreme heat in western europe in 2003: JJA temp 3.6 C above normal
- Italy: 36% maize reduction
- France: 30% maize and fodder (animal feed) reduction, 25% fruit reduction, 21% wheat reduction
- by 2100, years of similar temp stess on agriculture will be the norm throughout the tropics and subtropics due to the summer avg temp changes
impacts of climate change on food security
- increasing temp over the next 50 years will cause decreased in yield:
- decrease in grain filling
- decrease in spikelet fertility (not as many seeds formed)
- increased water stress
- increased respiration
- important for all crops, but esp for wheat, rice, soybeans, and maize
impacts of climate change
- reduced yields of wheat, rice, maize, and soybeans in the tropics/subtropics
- approximately -10% for each degree warming
- estimated reductions of 30-40% by 2100 in india, africa, middle east, central america, etc.
- reduced nutritional content (esp. in wheat and rice)
- increased disease transmission rates
indirect effects
- changes in pathogens and pests (yet unknown)
- increased CO2 and plants (enhanced growth rates for some plants, but benefits tend to be limited to extratropics though)
