Page:Popular Science Monthly Volume 20.djvu/686

666 consequently the total quantity of heat transferred from the tropics by this current amounts to 154,959,300,000,000,000,000 foot-pounds per diem. Even if we reduce this estimate one half, the stoppage of the Gulf Stream would still deprive the Atlantic of a quantity of heat equal to one fourth of all that is received directly from the sun by that area.

It is beyond doubt, therefore, that the passage of so great a body of heated water into the North Atlantic, over the surface of which it spreads for so many thousands of square miles, must have a most powerful influence on the climate of those regions to which its heat is brought by prevalent winds. This is the case more especially with France, our own islands, Norway, the Faröes, and Iceland. With us the prevalent winds are westerly and southwesterly, and these, as they sweep across the Atlantic, filch warmth and moisture from the Gulf Stream, which they part with as they pass over us in their course toward the northeast. How very materially our climate is thus affected will be readily seen if we compare the mean winter and summer temperatures of places in the same latitudes of North America and Europe. Thus at Bordeaux, in north latitude 44° 50', we have a winter temperature of +41° Fahr., and a summer mean of +69·1° Fahr., while at Halifax (Nova Scotia), in the same latitude (north latitude 44·39°), the winter mean is +22·6°, and that of summer +63·5°. Again, at Killybegs (Ireland), in north latitude 54° 38', the winter temperature is +41·4, and that of summer +58·7° the winter and summer means of a corresponding latitude on the Labrador coast being +5° and +49° respectively. Once more, at Wick (north latitude 58° 25') the winter temperature is +38·5°, and that of summer +56·5°, while at Hebron (Labrador), in north latitude 58° 16', we get a winter mean of -5·1° and a summer mean of +46·1°. Now t, were the Gulf Stream to be stopped, the temperature of the maritime regions of Northwestern Europe would probably fall as low as that of corresponding latitudes in America. In the event of that stream being diverted out of the North Atlantic, the polar currents flowing south would of course occupy the greater portion of the oceanic surface to the west of us, and hence our west and southwest winds would be cold and ungenial. Were such a catastrophe to happen, we may be sure that the Scandinavian Peninsula and a large part of our own islands would not be habitable by civilised man, while Iceland would become as inaccessible as Franz-Josef Land is now. Our own shores would be frost-bound for a large part of the year, and perennial snow and glaciers would appear in our mountain districts. On the other hand, if we could suppose the body of warm water now flowing into the North Atlantic to be largely increased in volume, there can be just as little doubt that the climate of Northwestern Europe would be much improved, and even Spitzbergen and Nova Zembla might be rendered fit abodes for civilized communities.