CHANGING CLIMATE

Hokitika Guardian, 1 March 1926, Page 1

CHANGING CLIMATE

AAEERICAN EXPERIENCE. RECORDED FACTS. (By Henry llolm Clayton, former Chief Forecast Division, Argentine. "Weather Service, now Co-operator with Smithsonian institution relating Solai Conditions and Weather.) ALr Clayton, one of America’s leading meteorologists, has spent the last ten years in studying world weatuer. M hen in Argentine he developed a method oi forecasting based upon the changes in the amount of heat radiated iront the Still. Our climate is slowly changing, decade by decade and century by century. Although the temperature year by year fluctuates w idely troin the average, there is an underlying trend in the northern United States and Canada like a slow!v rising tide, while in the south of the United States the trend is the other way. I bus the contrast between the weather of the north and -utilh is diminishing, and the climate of the country as a whole is ameliorat-

it has been widely held that- climate

is a. fixed quantity, and that it we have a long enough peril. ! el observation, stiy 30. 7)0 or R'D " 1 ‘ 1:111 average out the vagaries of the weather and determine the real climatic constant. That idea has given rice lo another widely held view, which is that, if the temperature or the rainfall, for example, is above normal for a, few years, then later it will be as much below normal, so that, in the course of time, the same average condition prevails. These ideas arc being abandoned o> advanced students of tin- weather, who hold that climate as well as weather is in a continuous state ol change. Thirty, fifty, or one hundred year averages have no meaning as indicating any fixed normal above and below which the temperature may oscillate, hut, will again return to the same level. The investigations of A. E. Douglass. Gerard Do Greer, Ellsworth 'Huntington and others have proved that climate, like the weather, or like the tides, is in a continuous process ol cbo and How, and hundreds, or even thousands, of years may intervene hclore the same condition returns. In intervals of time measured by nuiitv thousands ol years the climate of a. place like New England may change front, a condition where- ice covers the land surfaces to a depth ol thousands of feet to conditions so mild as to be almost tropical. Even in the course of several centuries the climate of New England may oscillate between cold conditions simiInr to those of Labrador and mild conditions similar to those which prevail on the coast ol Virginia at the present time.

Regular observaiions ol the temperature at Boston and at New Haven extend back almost to colonial times. Tito observations at New Haven began in 1778, and in Boston in 1700. The two sets of records run almost parallel. The mean annual temperature- of the past 50 years ol observation is materially higher than those of the first ->0 years. The coldest periods recorded were from 1782 to 1792. and from 1812 to 1823. Since then the trend of tho temperature lias Iteon upward. The mean temperature of the ton years ending with 1925 is two and six tenths warmer than the mean of the ten years ending with 1821. If danuary ami July are considered separately, if is found that the mean of the past ten Januaries has averaged four degrees warmer than the mean of the ten from 1812 to 1821, and the mean of the pa-i. ten Julys lias averaged one and .-even-tenths degrees warmer.

q’lhs progressive rise of temperature i- indicated by observai ions taken all over tho northern part of the United States. Tn St. Paul. Minn., the temperature of tho decade ending with 1925 averages two and eight-tenths degrees warmer than that ol the first decade of observation from 1859 to ISOS. Tn Canada the rise has been even more pronounced. At Winnipeg, for the ten years ending witli 1025, tlio average yearly temperature is four degrees higher 'than that of the first ten rear- of observation ending with 18S-I. The rise at- other Canadian stations, like Port Ai lliitr and Dawson, is even o rea tor. In Alaska, the period covered by the observations is comparatively •short. hid even these show a progressive advance in the mean temperature taken in leu-year averages. But the existence of milder conditions in Alaska is best told by 1 lie retreat of the glaciers ever since they were first, observed. This climatic change is all the more remarkable ltoeause in the southern part of the United States the tveml i* the other way. At Charleston. S.C.. the mean temperature of the ten years cndin* r with 1920 is nearly two degrees cnlder'than that of the first ten years „f observation from 1823 in 1832. and there has been a distinct trend dnwn--U San Diego. Cal., at El Paso. ■IVx,. and Key AYest. Fla., the trendare also downward. These fads indicate that the contrast in temperature between the northern States and the southern is di-

minishing. . i Will this ‘continue with backward ebbs and Hows like an incoming tide until wo are ushered into the mild temperature of an inter-glacial penod - Or are we now on the crest of some warmer period from which there will be a retreat? , No one at present can answer Hits, questions, but- one thing seems reliant, since we are now it. n long « milder years in the Northern Urn 1 States and Canada, wo cart be leasonablv sure that- there will not ho ajo turn of tin- cold winters ami cool summers which characterised tho >eai around 1819. although it <R llto Visible that the temperature of the '« i„.r winter or coining summer may be below the mean of (he past ten years But even the temperature of H •von,. 1810, which has been called a >eat without- a summer, was not so low as otic might he led to infer from >,s description The winter was cold, but not colder than many sulvsequoni winters. and the mean temperature of Ink- of that vein- in New haven was 05 8 decrees, which may l>e compared with GtTo in 1891 and 08.8 degrees tn 1914.