...THE NEGEV DESERT...
from the above link :
"The Negev (meaning "dry") makes up about 60% of the modern state of Israel (4600 sq. miles out of 8100 total). A narrow strip of it north of Beersheba gets, in good years, up to 14 inches (350 mm.) of annual rainfall, enough to grow barley. This northern Negev saw a fair amount of settlement in antiquity.
South of Beersheba, though, the annual rainfall drops below 8 inches. As far as the Ramon Crater (see map), wild plants still cover at least 10% of the surface, and this is grazing desert (midbar in Hebrew, which comes from davar, an ancient term for "grazing"). South of the Ramon Crater, however, plants are found only in the wadis. Here the desert can support no flocks. "
...ISRAELI AGRICULTURE...(from : israel ministry of foreign affairs website)...
from above article (this is indeed a very interesting article) :
"A combination of sophisticated, applied science, rugged determination and government support have helped Israel's farmers to modernize and adapt to changing geopolitical, market and climatic conditions, giving them a strong base from which to proceed in the coming decades.
Israel's agriculture continues to thrive, and supplies most of the country's food needs, though profitability in export sectors has declined sharply in recent years. Among the numerous problems the crop-growing sectors have contended with since the State was founded, water scarcity remains the principal - and growing - threat. Nevertheless the ongoing introduction of new and recycled water sources, coupled with altered irrigation methods and more water-efficient crops, promises long-term security."
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it seems pretty clear that without irrigation israel would not be able to grow many crops , and as the article points out , the future of agriculture
faces many problems .
looking at africa , there are some areas that have a sufficient water supply where various agricultural products can be grown .
where there is no water available (lack of rainfall) , it is next to impossible to grow grains .
i think the canadian prairies and the grainbelt of the united states showed what happens to grain production during periods of draught - the "dirty '30's " are still being talked about in north-america .
more recently the draught in australia seems to have wiped out grain production in australia (which has been to some advantage to north-american grain farmers ) .
from my limited understanding "heat" seems to drive away "rain" - looking at the sahara dessert and certain parts of australia seems to confirm that .
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...THE DIRTY THIRTIES...
The people of the Prairies suffered more than other Canadians. Not only did they lose the markets for their wheat, but a series of natural disasters also devastated the region.
The first was drought. Rain and snow, essential sources of moisture for the wheat crop, seemed to vanish in the early 1930s. Crops withered and died in the field. With no living plants to anchor the surface of the land, precious prairie topsoil and freshly-sown seeds were carried away by the wind.
The Prairies looked like a desert during this time, as the rich soil drifted into dunes that almost buried people along with their houses. Every farm house had drifts of dust on the window sills and floors. Dust even filtered into closets, cupboards and food. Sometimes people could not breathe without holding a wet cloth over their faces.
The drought brought a companion plague of grasshoppers that easily thrive and proliferate in a dry, warm spring season. Prairie grasshoppers eat the grain as it pokes out of the soil in early spring. They grow along with the grain, feeding on it at every stage, until they eventually kill the plant.
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...AUSTRALIA WHEAT FARMERS SUFFER DRAUGHT...
CANBERRA, Australia, Oct 27, 2006 (AP Online via COMTEX) -- Australian wheat farmers suffering under the worst drought in a century were preparing to reap their smallest harvest since the mid-1990s, a commodities forecaster said Friday.
Only 10.5 million tons will be harvested in the financial year that began July 1, the Australian Bureau of Agricultural and Resource Economics said, compared with 28 million tons grown in the previous year. If the figures hold, it will be the smallest crop since 1994-95.
Similar declines were expected for barley and canola - a drop that was also expected to send the price of beef cattle down as more animals are sent to slaughter due to lack of feed.
The declining harvests are expected to slash $4.7 billion, or 35 percent, from income from the three key grains in the previous year.
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i have not heard any scientists talk about benefits to canada from increased temperatures .
from what i understaand , a prolonged warming of the earth would result in increased draught - and decreased grain production .
i doubt that grains can be grown profitably using artificial irrigation - assuming that it would even be available .
hbg