Gloabal warming and food production

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THE GREENHOUSE EFFECT

HAROLD BERNARD

HARPER COLOPON BOOKS            1980

PART II

Chapter 4: The Return of the Dust Bowl (Continued)

Wheat, rust, and prickly pears

  • Wheat is the second most important US grain and comprises about 17% of our total grain production. There are seven different monthly mean precipitation and temperature variables that significantly influence wheat yields.
  • During the dust bowl days the average July temperature in western Kansas, the nation’s largest wheat-producing region, rose from 79ºF to 82ºF. July precipitation diminished 57%. The dryness stunted wheat growth, and the hot weather favored wheat rust. Other pests took advantage of the climate change.
  • Computer simulations suggest that wheat yields in Kansas under 1930s-type climate, could be reduced by about 15%.

The Ogallala Aquifer

  • Much of the irrigation in the wheat belt comes from the Ogallala Aquifer, a vast underground reservoir that is not recharged with surface water, providing for 6.5 million irrigated acres in Nebraska and 6 million in Texas.
  • In some places the water table has fallen 700 feet and is continuing to fall at a rate of 2 to 7 feet per year. A significant decline in irrigated farming is foreseen.

The resilient crop

  • Soybeans, which account for 14% of US grain production and 60% – 70% of all soybeans grown in the world, are affected by July precipitation and temperature.
  • Illinois is the soybean production leader. As August precipitation was greater than normal in the 1930s, soybeans might be the most resilient grain when dust bowl-type weather returns.

The Tillamook burn

  • By early August 1933 the forests were tinder boxes. Sparks from logging equipment touched off a fire that devoured as much lumber as all the lumber turned out by US sawmills the previous year.
  • Drought contributed to a second disastrous Oregon fire in 1936.

Will we have enough water?

  • By the year 2000 only three of the 18 federally designated water regions on the US mainland are expected to have adequate water supplies.

Synfuels and catch-22

  • Shale deposits in the Upper Colorado River Basin hold 60 times the nation’s proven reserves of liquid petroleum, but production brings about serious environmental problems.
  • A classic catch-22 situation may occur with the synfuels demanding already scarce water while at the same time contributing to carbon dioxide-induced warming that may lead to drought and even greater water scarcity.
  • The answer is to substantially reduce development of synfuels and energy sources dependent upon coal. That would mitigate the greenhouse threat, lower water demand, and lessen the possibility of a 1930s-type (or worse) drought.

Sixty cloudless days

  • If we persist in our advance down the fossil and synthetic fuel path, we may well find prolonged and severe drought lurking at the end of it.

Chapter 5: The Long Island Express

Hurricanes

  • Hurricane and tropical storm activity in the Atlantic, the Caribbean, and the Gulf of Mexico reached a modern maximum in the 1930s, when 21 tropical cyclones blossomed in 1933 and 17 in 1936. The current average is 9.
  • The 1930s brought Florida more tropical storms and hurricanes than any other decade this century.
  • If we persist in our fossil fuel folly, we should be prepared to deal with increasing numbers of, and perhaps increasing violence in, tropical storms and hurricanes early next century.

Chapter 6: Climatic Stress

  • The westerlies reached their maximum northward extent in the early 1930s. The attendant climatic warmth of the time is reflected in the greater number of state records for high temperatures and dryness set during the 1930s than during any other decade since the 1870s.
  • Heat equal to the 1930s has not since returned to the United States, but as we alter our climate with carbon dioxide, it could be one of the first actualizations of the greenhouse threat.

Forty-one days below zero

  • The climatic stress of the 1930s produced not only hot spells, but some memorable cold waves, as well. February 1936 was the coldest month ever in US history. January 1937 established records for monthly cold all over the West.
  • The anomalous 1930s cold spells closed out in 1938 with a parting shot at the Northeast. An early winter cold wave sent temperatures diving to below zero in late November – the earliest ever in Albany, New York, and Burlington, Vermont.

Drownings in the dust bowl

  • The climatic stress of the 1930s brought about not only great seasonal temperature contrasts, but contrasts in precipitation regimes as well. While the Midwest dried up under the onslaught of a great drought, record rains and floods decimated other regions.

Now is the time

  • It is apparent that climatic stress and a 1930s-type climate regime mean more than heat and dust and heightened tropical storm activity. They also mean paralyzing cold waves and destructive floods. They mean having to deal with climatic extremes at both ends of the weather spectrum.
  • Our ability to deal with climatic stress is suspect. Agricultural and economic planning are built around ‘normals,’ not extremes. The greenhouse threat promises not only to change those normals, but the extremes as well.
  • In talking of a return to a 1930s-style climate, we are talking of only a brief stop along the way, the first stages of the greenhouse effect, the first problems we may have to face.
  • If we persist in our pattern of fossil fuel consumption, the succeeding decades could bring a cascade of immense challenges – or immense disasters.
  • It would be far easier to meet those challenges now.

Chapter 7: The West Coast and Alaska – the 1930s

  • The following five chapters take a closer look at the overall climatological conditions that prevailed across the US during the 1930s, looking at mean climatic patterns on a month-by-month basis, and examining averages from the 1930s to see how they compare with current averages.
  • The statistics from the 1930s ought to have a great deal of relevance to our climatic future in the 2010-2020 time frame.

Chapter 11: The Eastern United States – the 1930s

A review: The Dust Bowl Decade

  • The most severe desiccation of the 1930s plagued the center of the nation, particularly the area from eastern Colorado through much of Nebraska and Kansas into Iowa. There, mean annual precipitation during 1930-1939 averaged 80% or less of current normals.
  • In most of Kansas and Oklahoma – the heart of America’s wheat-growing land – July rainfall during the 1930s averaged less than one-half of the modern normal. Wheat yields are significantly influenced by, among other factors, July precipitation.
  • The dust bowl-type weather was not generic to the entire nation during the 1930s. The eastern seaboard averaged somewhat cooler and wetter, although Januarys were often significantly milder – as was the case throughout the eastern half of the country.
  • Most of the West Coast, as well as the East Coast, experienced a relative cooling during the dust bowl decade, as did New Mexico and southwestern Texas.
  • The same persistent upper air circulation that can produce drought in the Midwest can bring increased amounts of rainfall to much of southern Texas and the southwestern United States and also reduced sunshine.
  • It appears as though the pattern of relative climatic changes that occurred during the dust bowl decade make meteorological sense. The changes were not universally of the same magnitude, nor even in the same direction.
  • They were the result of an altered atmospheric circulation pattern that went hand-in-hand with the hemispheric warming of the period. The alteration was not triggered by the greenhouse effect.

A hemispheric perspective

  • After I completed my analysis of US climatic data of the 1930s, the results of a somewhat similar work were published in a British scientific journal. The five warmest years during 1925-1974 averaged roughly 1ºF warmer than the five coldest.
  • The 1ºF figure is essentially how much warmer the 1930s were than now. Thus it seems likely the patterns obtained in the British work should roughly parallel the ones I came up with for the United States.
  • With the thought in mind that the British results probably give a general indication about hemispheric climatic patterns likely to accompany the first steps toward a ‘greenhouse world,’ let us consider these patterns
  • Maximum warming is shown in high latitudes and in continental interiors, with mean annual temperature rises in excess of 3.5ºF in northwest Canada, and from Finland across northernmost Russia and Siberia to about 120ºE.
  • Except as previously noted, all of North America is indicated to be warmer, as is most of Europe and Asia. Drying is spelled out not only for much of the United States, but for northern Mexico, most of Europe (especially France and Spain) and most of Russia, Turkey, across Africa west of 20ºE, from western China into much of southeast Asia, and for Japan and Korea.
  • Increased rainfall is suggested for other regions of the Northern Hemisphere: Alaska and much of Canada, most of Norway and Sweden, most of Yugoslavia and Greece, a large area of the Middle East, northern Africa east of 20ºE northwest Saudi Arabia, much of Pakistan and India, and most of eastern China and Mongolia.
  • Much of Europe and western Russia share in a combination of warming and drying. As in the United States, such a climatic trend would have serious, negative implications for agriculture.
  • In terms of humankind’s ability to feed the world, the threat is real and it is enormous. We may face no more important environmental challenge in our lifetime.

Chapter 12: The Ultimate Pollutant

  • Assuming that we do not deviate from our fossil fuel course within the next couple of decades, the carbon dioxide-produced climatic warming may begin to accelerate early next century.
  • From a climate similar to that of the 1930s in the period 2010-2020, we would go into one warmer than anything humankind has experienced in the last 1,000 years.
  • By 2020-2030 the hemisphere would be 2 or 3ºF warmer than it is now. To find an acceptable analog for such warmth we have to turn to a time known as the Medieval Warm period, or secondary climatic optimum (the primary climatic optimum occurred about 5,000 BC to 3,000 BC, and was the first major climatic epoch after the last ice age), which prevailed between 800 and 1200 AD.
  • Research climatologists estimate that the hemispheric temperature during those mild Middle Ages was almost 2ºF higher than at present.

English wines

  • The vineyards in western and middle Europe extended some 250 to 300 miles farther north and up to 600 feet higher above sea level than they do now, suggesting that summer temperatures there averaged nearly 2ºF warmer than today.
  • Artic pack ice melted so far back that appearances of drift ice in the waters near Iceland became virtually unknown between 1020 and 1200. The northern reaches of the Atlantic Ocean became relatively storm-free.
  • During the era in which the Vikings settled Greenland there was a record of unusually harsh frosts in the Mediterranean, the Tiber River in Rome and even the Nile in Cairo froze over once or twice, and winters in western Europe were often on the severe end of the scale.

A 200-year drought

  • Precipitation patterns, as well as temperature regimes, changed during the Medieval Warm Period. Archeological studies suggest that Minneapolis, Minnesota around the year 1000 was warm and dry.
  • The pollen records confirm a dwindling number of trees and an increase in short prairie grasses during the 1100s, due to an unprecedented drought that lasted for 200 years.
  • Dr. Reid Bryson of the University of Wisconsin points out, “Clearly two hundred years of drought in the ‘breadbasket’ of North America is possible.”
  • The analogs squeezed into the 2010 to 2030 time frame warn of 15 to 20 years of severe desiccation and record-breaking heat.
  • Ever so slowly – we would not even notice it at first – the sea level would begin to rise. Thin layers of polar ice would start melting.

The West Antarctic Ice Sheet

  • By the year 2040 our climatic temperature may soar beyond anything known within the past 125,000 years. The average hemispheric temperature could be as much as 5ºF above what it is now.
  • We can guess, although we do not know for certain, that the great mid-continent drought would persist, perhaps centering over the northern United States and southern Canada.
  • Summertime temperatures on the Great Plains might frequently reach or exceed 120ºF. US agriculture would be struggling to survive, frantically trying to adjust to vastly altered patterns of temperature and rainfall. Food prices would soar and rationing might become necessary.
  • In the southern hemisphere, the West Antarctic Ice Sheet would begin to disintegrate – climatic warming is magnified in the polar regions. Within a matter of several hundred years the sea level around the world would rise by an average of 16 or 17 feet.
  • Other permanent ice and snow melt would contribute to the elevating seas, and the total rise could be as much as 60 feet. We would lose our coastal cities.
  • The 60 foot figure assumes that the climatic warming stops at that point. If it continues, the oceans would claim more of the world’s coastal land masses. The melting of the East Antarctic Ice Sheet alone would add another 165 feet of water to the earth.
  • The western sheet would add only 16 or 17 feet because it is smaller, and because it is largely sea ice – which only displaces ocean water.
  • While neither we nor our children will live to see the oceans rise significantly, we are the generations who will have to make the decision as to whether we risk sacrificing most of Florida in centuries to come.
  • Once the greenhouse threat becomes reality there is no turning back the inexorable ice melt and the eventual takeover of our coastal homes by the seas.

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