Urdhero dhe nje artikull te Newsweek, te vitit 1975 ne lidhje me "Glabal Cooling", meqe doje fakte!
April 28, 1975
The Cooling World
There are ominous signs that the Earths weather patterns have begun to change dramatically and that these changes may portend a drastic decline in food production with serious political implications for just about every nation on Earth. The drop in food output could begin quite soon, perhaps only 10 years from now. The regions destined to feel its impact are the great wheat-producing lands of Canada and the U.S.S.R. in the North, along with a number of marginally self-sufficient tropical areas parts of India, Pakistan, Bangladesh, Indochina and Indonesia where the growing season is dependent upon the rains brought by the monsoon.
The evidence in support of these predictions has now begun to accumulate so massively that meteorologists are hard-pressed to keep up with it. In England, farmers have seen their growing season decline by about two weeks since 1950, with a resultant overall loss in grain production estimated at up to 100,000 tons annually. During the same time, the average temperature around the equator has risen by a fraction of a degree a fraction that in some areas can mean drought and desolation. Last April, in the most devastating outbreak of tornadoes ever recorded, 148 twisters killed more than 300 people and caused half a billion dollars' worth of damage in 13 U.S. states.
To scientists, these seemingly disparate incidents represent the advance signs of fundamental changes in the world's weather. Meteorologists disagree about the cause and extent of the trend, as well as over its specific impact on local weather conditions. But they are almost unanimous in the view that the trend will reduce agricultural productivity for the rest of the century. If the climatic change is as profound as some of the pessimists fear, the resulting famines could be catastrophic. A major climatic change would force economic and social adjustments on a worldwide scale, warns a recent report by the National Academy of Sciences, because the global patterns of food production and population that have evolved are implicitly dependent on the climate of the present century.
A survey completed last year by Dr. Murray Mitchell of the National Oceanic and Atmospheric Administration reveals a drop of half a degree in average ground temperatures in the Northern Hemisphere between 1945 and 1968. According to George Kukla of Columbia University, satellite photos indicated a sudden, large increase in Northern Hemisphere snow cover in the winter of 1971-72. And a study released last month by two NOAA scientists notes that the amount of sunshine reaching the ground in the continental U.S. diminished by 1.3% between 1964 and 1972.
To the layman, the relatively small changes in temperature and sunshine can be highly misleading. Reid Bryson of the University of Wisconsin points out that the Earths average temperature during the great Ice Ages was only about seven degrees lower than during its warmest eras and that the present decline has taken the planet about a sixth of the way toward the Ice Age average. Others regard the cooling as a reversion to the little ice age conditions that brought bitter winters to much of Europe and northern America between 1600 and 1900 years when the Thames used to freeze so solidly that Londoners roasted oxen on the ice and when iceboats sailed the Hudson River almost as far south as New York City.
Just what causes the onset of major and minor ice ages remains a mystery. Our knowledge of the mechanisms of climatic change is at least as fragmentary as our data, concedes the National Academy of Sciences report. Not only are the basic scientific questions largely unanswered, but in many cases we do not yet know enough to pose the key questions.
Meteorologists think that they can forecast the short-term results of the return to the norm of the last century. They begin by noting the slight drop in overall temperature that produces large numbers of pressure centers in the upper atmosphere. These break up the smooth flow of westerly winds over temperate areas. The stagnant air produced in this way causes an increase in extremes of local weather such as droughts, floods, extended dry spells, long freezes, delayed monsoons and even local temperature increases all of which have a direct impact on food supplies.
The worlds food-producing system, warns Dr. James D. McQuigg of NOAAs Center for Climatic and Environmental Assessment, is much more sensitive to the weather variable than it was even five years ago. Furthermore, the growth of world population and creation of new national boundaries make it impossible for starving peoples to migrate from their devastated fields, as they did during past famines.
Climatologists are pessimistic that political leaders will take any positive action to compensate for the climatic change, or even to allay its effects. They concede that some of the more spectacular solutions proposed, such as melting the Arctic ice cap by covering it with black soot or diverting arctic rivers, might create problems far greater than those they solve. But the scientists see few signs that government leaders anywhere are even prepared to take the simple measures of stockpiling food or of introducing the variables of climatic uncertainty into economic projections of future food supplies. The longer the planners delay, the more difficult will they find it to cope with climatic change once the results become grim reality.
Reprinted from Financial Post - Canada, Jun 21, 2000
All Material Subject to Copyright.
Ja dhe nje tjeter:
Global cooling, again.
I wrote about the Global cooling myth on RealClimate a while ago; and there is a more complete but less organised set of stuff at http://www.wmconnolley.org.uk/sci/iceage/. I had hoped that the RC peice would throw up some interesting new references; but only one appeared:
From Physical Geology by Eugene Mitacek, 1971:
WILL THE ICE AGES RETURN? Climatologists report that the world's weather is turning sharply cooler. Signs of this are evident. Drifting icefields have hindered access to Iceland's ports for the first time in this century. Since 1950 the growing season in England has been shortened by two weeks. Director Reid Bryson of the Institute for Environmental Studies at the University of Wisconsin reports that, if this trend continues, it will affect the whole human populace.
A long term study of climactic conditions would place the first half of the twentieth century into an exceptionally warm period. The warming trend peaked in 1945, and the temperatures have been dropping since. The drop to date is on 1.5 degrees C, far from the 10 degrees C drop necessary for a new Ice Age. If this trend is not reversed, however, the planet may be caught in an ice-forming cycle similar to that of the Pleistocene.
That quote is probably copied from http://www.kuro5hin.org/story/2001/3/2/03449/27856. Note that the drop-to-date of 1.5 oC is wrong (by todays climatology, and probably by what they had then). The global cooling from peak (1940's) to trough (1970's) is barely 0.2 oC (see the SPM) and the northern hemisphere only somewhat larger (about 0.3 oC: see fig 2.7). If you took peak-to-trough for individual years (which you shouldn't, because only slightly different years would then get you a warming) you might get 0.6 oC. But not 1.5 oC. However, thats from modern records: what was available at the time might be wilder.
The reference turns out to be wrong (initially I suspected it might simply be invented, but no). The real ref is Physical Geology, Principles, Processes, and Problems by Charles J. Cazeau, Robert D, Hatcher, Jr.; and Francis T. Siemankowski, 1976 (not 1971; thats a relief because 1971 would be an implausible date for a quote of this sort). The confusion arises because the endpapers are a geological chart by Mitacek, which *is* copyright 1971. With the ref sorted out (thanks JM) I got a copy from abebooks, which arrived today (the wonders of the internet; once apon a time getting hold of a copy would have been too tedious to bother with).
However although the ref needed correction the quote, somewhat to my surprise, is in context (you wouldn't believe the out-of-context quoting that goes on elsewhere). The book continues (thanks JM):
Long range weather forecaster Edward M. Brooks believes that the present cooling trend follows a 40-year cyclic pattern. He feels that this trend will continue until 1985. We will not need to wait much longer to see if the trend will reverse. Both Bryson and Brooks are in agreement, however, that the world is heading into a period of weather unfavorable for agriculture. This is extremely bad news because of the explosion of population in many countries of the world. It appears as if we will be producing less, rather than more, food. As food reserves dwindle we may move into a period of massive, unimaginable tragedy. Long-range plans to feed as ever-growing population must be made.
In the last paragraph of the chapter it also says the following:
It is difficult to forecast the outcome of the present cooling trend. Climatologists differ regarding whether a new Ice Age lies ahead. There is agreement, however, in predictions of shorter growing seasons and lower crop yields for the next 10 years.
Now, what do I say to this? Bad news for the good guys? Well no (surprised?). I think it accurately reports Brysons views, but not the general views of the time. The views of the time were "we don't have good enough theory and measurements to predict the future (100 years) climate, and we know it" (see, e.g., the conclusions of the NAS report, 1975). This is a textbook, not the primary literature. So how do we explain the presence of this stuff in a textbook? Its only a tiny fraction (less than one page out of more than 500) and its a geology book not a climatology book. Textbooks are (I presume) not peer-reviewed in the way papers are; and even if it was reviewed it would have been sent to geologists, since its a geology book. People often make mistakes when they go out of their field...