NO. 6 PAST CLIMATE OF NORTH POLAR REGION BERRY I7 



This brief statement will be sufficient to indicate that there are other 

 and more important factors than cold. The almost entire absence 

 of vascular plants (a single species as I recall it) from Antarctica 

 shows the part geography plays in the problem. The absence of trees 

 in Lapland (Kihlman) shows the part taken by cold desiccating winds. 

 The northern limits of many tree species in coastal Alaska and Nor- 

 way will indicate the ameliorating climatic effects of warm ocean cur- 

 rents and humidity. 



i-XISTING ARCTIC CLIMATES 



This is a complex subject which cannot be discussed in this con- 

 nection be}ond pointing out certain observed facts which support the 

 thesis of the present discussion. These are the slower heating and 

 cooling of water bodies as compared with land areas, with their respec- 

 tive influence on air temperatures and pressures, their influence on 

 the amount of water vapor in the air and the resulting effect of 

 humidity on equability. 



The climatic influence of the northward drift of oceanic waters 

 may be illustrated l)y the course of the present day isotherms over the 

 north Atlantic, a somewhat hackneyed illustration but nevertheless the 

 most striking. I am showing a few of the isotheims for January and 

 July in figures 5 and 6. Those for January which show the full effect 

 of the rapid radiation and quick cooling of the land, contrast most 

 markedly with the slow radiation and cooling of the ocean. At this 

 time the zero isotherm reaches Latitude 35° in Asia and about Lati- 

 tude 74^" north of Xorway, a difference of 39°. ^luch the coldest place 

 is in northern Siberia which is 10° to- 20° colder than at the pole itself. 



The —30'^ isotherm reaches almost to the pole north of the Atlantic 

 and swings to approximately Latitude 55° in Siberia — a difference of 

 alx)Ut 35° of latitude. The midsummer isotherms naturally smooth 

 out these curves somewhat but even at this season the isotherm of 5° 

 swings from about 62° in southern Greenland to 80° just west of 

 Spitzbergen and the oceanic effect is clear as far eastward as Nova 

 Zembla. 



A few figures quoted from vSir John Murray's calculations will 

 serve to emphasize the relations referred to. The energy radiated 

 by the lowering of the temperature of a cubic meter of water 1° is 

 sufficient to raise the temperature of more than 3,000 cubic meters of 

 air 1°, and a second calculation shows that the heat released by lower- 

 ing by 1° a stratum of water 200 meters deep and of 700,000 square 

 kilometers area would suffice to raise the temperature of a stratum 



