The forces that shape our climate are also critical to farm productivity
The National Farmers’ Federation has suggested that climate change is possibly the biggest risk facing Australian farmers over the coming century
Temperature: An increase in average temperature can affect:
engthen the growing season in regions with a relatively cool spring and fall;
adversely affect crops in regions where summer heat already limits production;
increase soil evaporation rates
increase the chances of severe droughts.
Rainfall, floods and severe storms: Changes in rainfall can affect:
soil erosion rates and soil moisture
tropical cyclones, droughts and flooding rains impact on food production and supply
wildfires cause loss of fodder, animals, and farm infrastructure (sheds, fences, machinery)
hail causes significant crop losses
the increased risk and rates of salinization http://www.epa.gov/climatechange/effects/agriculture.html
2% is used for broad acre and intensive crop production
4% is sown to pastures
50% of the gross value of farm production is cropping,
25% of the gross value of farm production is meat production
25% of the gross value of farm production are livestock products such as wool and milk
a 20% reduction in rainfall at doubled CO2 is likely to reduce pasture productivity by about 15% and live-weight gain in cattle by 12% Howden et al. (1999d)
the response of dairy cattle to heat stress
heat stress in beef cattle
Physiological effects of heat stress include
and Turnpenny (1997) and Howden et al. (1999e)
The agriculture sector is vulnerable to the potential impacts of climate change including:
a reduction in annual average rainfall over much of the Australian continent
increases in mean annual temperature and atmospheric carbon dioxide concentrations
increased frequency of extreme weather events such as flooding and drought
altered distribution and survival of pests and weeds, which are likely to have a significant impact on agricultural production in some regions
increased risk of heat stress for intensively housed animals
Warmer temperatures may also increase the distribution of weeds, pests and diseases
the likely impacts on different types of agriculture.
Some potential impacts from climate change
Grazing & livestock
Heat Stress in Corn – poor kernel formation A9b_s1_2
Examples of climatic sensitivities in agriculture
The grains industry, Australia’s largest crop based industry, is sensitive to the timing of frosts, sowing
rains and rain in spring. In addition, cumulative temperature impacts may be important, as well as
increases in wind speed.
The dairy industry is vulnerable to climate change, especially because of the sensitivity of dairy
cattle to heat stress (high temperature coupled with high humidity).
Sheep and beef cattle
The timing and seasonal patterns of rainfall are important for pasture based livestock industries.
The extensive beef production industry has learned to cope with regionally variable rainfall; it is
more adaptable than many rural industries. For the sheep industry, cold events (wind, rain, and low
temperature in combination) are a common risk for recently shorn and new born animals.
Hail storms and frosts are major climatic risks for the fruit industry.
For apples and pears, the timing of rainfall is important; in dry conditions the availability of irrigation water is crucial. Higher night temperatures can be a problem for some late harvested varieties of fruit.
For the viticulture industry, the timing of rainfall is critical. Late summer rainfall can lead to splitting,
ringing, disease exposure and rot. Generally wet summer conditions can lead to fungal and bacterial
infection from the soil. Frosts at bud burst and fl owering can also devastate yields.
Source: Steffen and Sims (2006).
Most Important Crops Hit
By Global Warming Effects http://www.countercurrents.org/cc-connor230307.htm 23 March, 2007
warming over the past two decades has already had real effects on global food supply Rising temperatures between 1981 and 2002 caused aloss in production of wheat, corn and barley that amounted in effect to some 40 million tons a year - equivalent to annual losses of some £2.6bn.
six of the most widely grown crops in the world - wheat, rice, maize, soybeans, barley and sorghum. Production of these crops accounts for more than 40 per cent of the land in the world used for crops, 55 per cent of the non-meat calories in food and more than 70 per cent of animal feed
cereal crops are suffering from lower yields during a time when agricultural technology, including the use of chemical fertilisers and pesticides, has became more intensive. the observed fall in cereal yields could be clearly linked with increased temperatures between 1980 and 2002 - around the world during a period when average temperatures rose by about 0.7C although the rise was even higher in certain crop-growing regions of the world. David Lobell of America's Lawrence Livermore National Laboratory in California,