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milankovitch cycles鈥攖hat it is asdifficult to prehend the events of the past as it is to predict those of the future。 much issimply beyond us。 take antarctica。 for at least twenty million years after it settled over thesouth pole antarctica remained covered in plants and free of ice。 that simply shouldn鈥檛 havebeen possible。
no less intriguing are the known ranges of some late dinosaurs。 the british geologiststephen drury notes that forests within 10 degrees latitude of the north pole were home togreat beasts； including tyrannosaurus rex。 鈥渢hat is bizarre；鈥潯e writes； 鈥渇or such a highlatitude is continually dark for three months of the year。鈥潯oreover； there is now evidencethat these high latitudes suffered severe winters。 oxygen isotope studies suggest that theclimate around fairbanks； alaska； was about the same in the late cretaceous period as it isnow。 so what was tyrannosaurus doing there？ either it migrated seasonally over enormousdistances or it spent much of the year in snowdrifts in the dark。 in australia鈥攚hich at that time was more polar in its orientation鈥攁 retreat to warmer climes wasn鈥檛 possible。 howdinosaurs managed to survive in such conditions can only be guessed。
one thought to bear in mind is that if the ice sheets did start to form again for whateverreason； there is a lot more water for them to draw on this time。 the great lakes； hudson bay；the countless lakes of canada鈥攖hese weren鈥檛 there to fuel the last ice age。 they were createdby it。
on the other hand； the next phase of our history could see us melting a lot of ice rather thanmaking it。 if all the ice sheets melted； sea levels would rise by two hundred feet鈥攖he heightof a twenty…story building鈥攁nd every coastal city in the world would be inundated。 morelikely； at least in the short term； is the collapse of the west antarctic ice sheet。 in the past fiftyyears the waters around it have warmed by 2。5 degrees centigrade； and collapses haveincreased dramatically。 because of the underlying geology of the area； a large…scale collapseis all the more possible。 if so； sea levels globally would rise鈥攁nd pretty quickly鈥攂y betweenfifteen and twenty feet on average。
the extraordinary fact is that we don鈥檛 know which is more likely； a future offering us eonsof perishing frigidity or one giving us equal expanses of steamy heat。 only one thing iscertain： we live on a knife edge。
in the long run； incidentally； ice ages are by no means bad news for the planet。 they grindup rocks and leave behind new soils of sumptuous richness； and gouge out fresh water lakesthat provide abundant nutritive possibilities for hundreds of species of being。 they act as aspur to migration and keep the planet dynamic。 as tim flannery has remarked： 鈥渢here is onlyone question you need ask of a continent in order to determine the fate of its people： 鈥榙id youhave a good ice age？鈥櫋♀�潯nd with that in mind； it鈥檚 time to look at a species of ape that trulydid。
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28 THE MYSTERIOUS BIPED
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just before christmas 1887； a young dutch doctor with an un…dutch name； marieeug猫ne fran？ois thomas dubois； arrived in sumatra； in the dutch east indies； with theintention of finding the earliest human remains on earth。
1several things were extraordinary about this。 to begin with； no one had ever gone lookingfor ancient human bones before。 everything that had been found to this point had been foundaccidentally； and nothing in dubois鈥檚 background suggested that he was the ideal candidate tomake the process intentional。 he was an anatomist by training with no background inpaleontology。 nor was there any special reason to suppose that the east indies would holdearly human remains。 logic dictated that if ancient people were to be found at all； it would beon a large and long…populated landmass； not in the parative fastness of an archipelago。
dubois was driven to the east indies on nothing stronger than a hunch； the availability ofemployment； and the knowledge that sumatra was full of caves； the environment in whichmost of the important hominid fossils had so far been found。 what is most extraordinary in allthis鈥攏early miraculous； really鈥攊s that he found what he was looking for。
at the time dubois conceived his plan to search for a missing link； the human fossil recordconsisted of very little： five inplete neandertal skeletons； one partial jawbone of uncertainprovenance； and a half…dozen ice…age humans recently found by railway workers in a cave at acliff called cro…magnon near les eyzies； france。 of the neandertal specimens； the bestpreserved was sitting unremarked on a shelf in london。 it had been found by workers blastingrock from a quarry in gibraltar in 1848； so its preservation was a wonder； but unfortunatelyno one yet appreciated what it was。 after being briefly described at a meeting of the gibraltarscientific society； it had been sent to the hunterian museum in london； where it remainedundisturbed but for an occasional light dusting for over half a century。 the first formaldescription of it wasn鈥檛 written until 1907； and then by a geologist named william sollas鈥渨ith only a passing petency in anatomy。鈥�
so instead the name and credit for the discovery of the first early humans went to theneander valley in germany鈥攏ot unfittingly； as it happens； for by uncanny coincidenceneander in greek means 鈥渘ew man。鈥潯here in 1856 workmen at another quarry； in a cliff faceoverlooking the d眉ssel river； found some curious…looking bones； which they passed to alocal schoolteacher； knowing he had an interest in all things natural。 to his great credit theteacher； johann karl fuhlrott； saw that he had some new type of human； though quite what itwas； and how special； would be matters of dispute for some time。
many people refused to accept that the neandertal bones were ancient at all。 august mayer；a professor at the university of bonn and a man of influence； insisted that the bones were1though dutch； dubois was from eijsden； a town bordering the french…speaking part of belgium。
merely those of a mongolian cossack soldier who had been wounded while fighting ingermany in 1814 and had crawled into the cave to die。 hearing of this； t。 h。 huxley inengland drily observed how remarkable it was that the soldier； though mortally wounded； hadclimbed sixty feet up a cliff； divested himself of his clothing and personal effects； sealed thecave opening； and buried himself under two feet of soil。 another anthropologist； puzzlingover the neandertal鈥檚 heavy brow ridge； suggested that it was the result of long…term frowningarising from a poorly healed forearm fracture。 （in their eagerness to reject the idea of earlierhumans； authorities were often willing to embrace the most singular possibilities。 at about thetime that dubois was setting out for sumatra； a skeleton found in p茅rigueux was confidentlydeclared to be that of an eskimo。 quite what an ancient eskimo was doing in southwestfrance was never fortably explained。 it was actually an early cro…magnon。）it was against this background that dubois began his search for ancient human bones。 hedid no digging himself； but instead used fifty convicts lent by the dutch authorities。 for a yearthey worked on sumatra； then transferred to java。 and there in 1891； dubois鈥攐r rather histeam； for dubois himself seldom visited the sites鈥攆ound a section of ancient human craniumnow known as the trinil skullcap。 though only part of a skull； it showed that the owner hadhad distinctly nonhuman features but a much larger brain than any ape。 dubois called itanthropithecus erectus （later changed for technical reasons to pithecanthropus erectus） anddeclared it the missing link between apes and humans。 it quickly became popularized as 鈥渏avaman。鈥潯oday we know it as homo erectus。
the next year dubois鈥檚 workers found a virtually plete thighbone that lookedsurprisingly modern。 in fact； many anthropologists think itis modern； and has nothing to dowith java man。 if it is an erectus bone； it is unlike any other found since。 nonetheless duboisused the thighbone to deduce鈥攃orrectly； as it turned out鈥攖hat pithecanthropus walkedupright。 he also produced； with nothing but a scrap of cranium and one tooth； a model of theplete skull； which also proved uncannily accurate。
in 1895； dubois returned to europe； expecting a triumphal reception。 in fact； he met nearlythe opposite reaction。 most scientists disliked both his conclusions and the arrogant manner inwhich he presented them。 the skullcap； they said； was that of an ape； probably a gibbon； andnot of any early human。 hoping to bolster his case； in 1897 dubois allowed a respectedanatomist from the university of strasbourg； gustav schwalbe； to make a cast of the skullcap。
to dubois鈥檚 dismay； schwalbe thereupon produced a monograph that received far moresympathetic attention than anything dubois had written and followed with a lecture tour inwhich he was celebrated nearly as warmly as if he had dug up the skull himself。 appalled andembittered； dubois withdrew into an undistinguished position as a professor of geology at theuniversity of amsterdam and for the next two decades refused to let anyone examine hisprecious fo