-7The slgolflcance of a teDperature 1nclease of the aagnitude pledlcted by l.lanabe and Wetherald wlth respect to the long tero record of clLaate 1s presented ln Vugraph 11 whlch was prepared by M1tche1113. lhls flgure sholrs lhat the expected temperaiure lncrease would be large even cmpared to lhe teEperatules at the tlne of the last intelg1aclal. As thls tenperature Lncrease decayed, however, lt would replesent an aoelloration of an expected natural coollng trend. III. The Potentlal Probleus Arlslng froa a Globa1 Teoperature Increase fhe lEpllcatlons arlslng froa l'lanabe and ldetherald's predictlous fo! the teoperature effects resultlng fron a doubllng of carbon dloxlde concentrallons ln tbe atuosphere are outllned ln Vugraph 12. It appears falrly certain that 1f the hlgh lncreaseg they predl.ct in Ehe pola! reglons do occur, the perEanent 6no!r cove! and floatlug sea lce wtl1 be reduced or posslbly ellDlnated. Thls w1ll have a negliglble effect on sea 1eveJ., horrever, slnce the gnon cove! does not represent an appreclable aaou8t of water and the floatlDg lce ls already 1n equilibrlum r'1th lhe sea. Thele lr11l probably be no effect on the polar lce sheets. These are thlee Ln nu&ber. The Greenland lce sheet ln the Northero Uenlsphele represents an anount of nater equlvalent to a flve eeter rlse 1n sea 1eve1. If the floatlng sea ice Ls reuoved, the creenland ice cap would be surrounded by water. Ttris nlght produce lncreased precipl.tation and actually result ln the gronth of thls lce Eheet. The worldrs largest 1ce sheet ls the East Antalctic Eheet lrhlch contalns vater equlvalent to a rlse of 70 Deters ln the worldrs oceaDg. It is eetlnated that the teEperature effecls produced by doublltrg the atmosphellc C02 concentratlon nould not sffect thls vely large glacler and that lt too rdght lncreage 1n slze. The erea on vhleh oost uncertalnty exlsts ls nith lespect to the West Antarctlc lce sheet. The nate! Ln thls glacler ls equivalent to about e seven Deter rlse ln the worldt6 oceans. The West Anlalctlc 1ce sheet extends out ove! the ocean f1oor. I{arnet ocears Dlght result 1n aD lntru61on of the ocean waters underaeaih thls Lce sheet and a decrease ln 1ts slze nlght occur. If thls happens, an oceaaic rlse of sone ftactlon of the Eaxleua aaount (7 Detels) Dighr take place. Wllh a lraaer cllnate around the world, it seens falrly certaln preclpltatlon rould lncrease. 0n a g1obal basls, thls should rethat sult ln e lengthenLng of the grovLng season. Glolrlug seasona are eatilrated to increase about ten days for each loC rlse 1o teoperature. The ehauglng preclpltatlon patterns, however, lrould beneflt soue arees end nould harm others. It ls not poss1b1e, on the basls of present lnforratlor., to predlct Just where these effects would occur. As a fllst e6tLuete, one nlght say that the cllDatlc zones 1n the lrorld would nove nolthwafd, The effect of thls on the agriculture of the U,S. and RuseLa 16 ludlcated ln Vugraph 13.