Showing papers on "Climate change published in 1973"

The Chemical Basis for Climate Change

Abstract: It is obvious that the climate of the planet earth has undergone many rather drastic changes in the past, and there is every reason to believe that there will be other changes in the future. The question is not whether our climate will change, but rather: What causes it to change? If we knew the answer, perhaps we would be able to foresee the future climates in store for us.

Planetary Alignments, Solar Activity and Climatic Change

Abstract: Historical data suggest a relation between the changing level of solar activity and climatic change on Earth. Since there is also evidence that the solar cycle of activity is influenced by the alignments of the planets, through tidal interactions with the Sun, it seems that climatic change might be predicted by studying these alignments.

Glacier in Chile Ended a Major Readvance about 36,000 Years Ago: Some Global Comparisons.

Abstract: About 36,000 carbon-14 years ago, a glacier in southern Chile reached the culmination of a major readvance. Severe global cooling at about that time, preceded and followed by warmer conditions, is implied also by other glacial, floral, and some oceanographic evidence, but not by other oceanographic evidence nor by studies of past eustatic sea levels. Severe global cooling at about that time is incompatible with the Milankovitch theory of climatic change.

Consequences of Cycles in East African Climate

Abstract: Western and Van Praet1 have convincingly suggested that losses of yellow fever-trees in the Maasi Ambolesi are not due to over-population by cattle or elephants but to a climatic change causing a shift in the salt table. They assume that the change is part of a cycle, though of a much smaller range than has occurred in the past 10,000 yr. Perhaps inadvertently, they seem to suggest that the cycle producing the present vegetation change lasts about a century. Much shorter cycles than this may, however, be usual in the region, as evidence from further south suggests. It is important that this should be appreciated because, as the authors state, investment by governments on developments to accommodate tourists may be wasted if the climate is wrongly forecast.

Mass Biotal Extinctions, World Climate Changes, and Galactic Motions: Possible Interrelations

Abstract: Mass biotal extinctions have been attributed to numerous causes ranging from cosmic radiation to epidemic diseases. One cause commonly mentioned to explain the mass extinctions of Permian and Triassic times is a eustatic sea-level change during which epicontinental seas — the breeding grounds of thousands of marine taxa — were virtually eliminated from the continents. As a result of late Paleozoic orogenies and the sea withdrawals, large land areas were exposed and ecologic niches were eliminated and/or reduced drastically in size. It is almost certain that large-scale eustatic sea-level lowering and exposure of large land areas were related closely to the mass extinctions of Permian and Triassic times. However, these are not likely to have been the only causes, because the extinctions of numerous marine taxa took place during both Late Permian and Late Triassic times, whereas major extinctions of tetrapod faunas and land floras are mainly Late Triassic phenomena. The great sea withdrawals during Permian time were accompanied by a worldwide climate change from an Early Permian glacial-maximum condition (frigid, temperate, and torrid zones were well developed) to a latest Permian-Triassic evaporite-maximum condition (a nearly uniform worldwide climate in which only temperate and torrid zones were developed). Evaporite-maximum conditions persisted through Triassic time, and epicontinental seas continued to be scarce. At the end of Triassic time and during Early and Middle Jurassic time, an abrupt change took place to a cool, wet climate similar to that of the middle part of the Permian. This climatic change caused a marked alteration to take place in the vegetation, and many herbivorous tetrapods, accustomed to certain plant foods, no longer had these accessible to them. Almost simultaneously, epicontinental seas began to transgress large areas of the continents through Jurassic time. Therefore, the great faunal and floral “crisis” of Permian and Triassic times appears to have been caused by several factors acting together: eustatic sea-level lowering, orogeny, continental emergence, major climate change, and important changes in vegetation. Finally, Late Permian through Triassic time seems to have been a period when the solar system was passing through the perigalactic part of its orbit, with the result that the effects of climatic change were intensified.

On the West Greenland Sea-life Area of the Atlantic Salmon

Abstract: ... It is the contention of this present note that the West Greenland salmon fishery at least, and probably the other two as well, have come into existence because the salmon themselves have quite recently shifted their sea-life feeding area in response to marine climatic change. The salmon which now appear in west Greenland waters swim very close to the surface and are taken in surface drift nets. The West Greenland waters have been fished and hunted for some four centuries. ... It is entirely unreasonable to believe that, had the salmon been in these waters during such a period of time, they could have escaped detection and exploitation long since. ... Marine (hydrospheric) climates differ from atmospheric climates in that the response of the living populations associated with marine climate changes is immediate, at least as regards planktonic and nektonic communities: there is clearly a lag in the response of benthonic attached and in-faunal communities. We have abundant evidence of drastic changes in the marine climate of the North Atlantic and Subarctic area, particularly in West Greenland waters, during the past century. The increase in temperature since about 1915, which lasted into the 1940s, and brought the Atlantic cod fishery into existence in that region, is especially well documented .... It may be assumed that one selective advantage in the evolution of salmon migration is the attainment of marine regions of high food production; such regions are not stationary in the long term, or even in the comparatively short term, but are dependent on patterns of nutrient production and advection, which are in turn dependent on the changing pattern of wind and current. ... The patterns of migration, and of breeding area, of many marine animals have changed most significantly in recent decades in association with, but not necessarily directly caused by, change in marine climate .... It is therefore reasonable to search for means of navigation, in terms of information used by the migrants, which have also changed during the same period. Of the means so far considered, only two, those of the electric field and of olfactory information, change rapidly enough to be relevant in the present context. If ocean currents carry their own identifying smells and tastes ... then olfactory information may well be involved, but it is the possibility of the relevance of the electric field that is put forward here. It has been suggested by several workers ... that oceanic electrical information may be used by migrating animals .... The potentials developed by the passage of ocean currents through the earth's magnetic field are proportional to the velocity and transport of the current, and therefore the pattern must change as current velocities change; and changes in transport and velocity are clearly involved in changes in hydrospheric climate .... If electric fields are used in migration of fish, therefore, we should expect the migrational routes and termini to change with the climatic cycle. ... Shifts in the distribution and migration of marine exploitable species are of immense economic and international importance, and underline the urgent necessity for far better understanding of entire processes controlling changes in marine climate. ...