Isikhathi sokugcina seqhwa nokuthi abantu bafika kanjani eMelika

Ngeshwa, sisetshenzisiwe ukubona imiphumela yokuguquka kwesimo sezulu. Izwe elishisa ngokwengeziwe nemiphumela yokwanda okuqhubekayo nokuqhubekayo kokushisa. Izinto eziningi esizibona zenzeka nanamuhla, bezingafani nalezo phambilini. Ikhaya lethu, iplanethi enguMhlaba, libe nezikhathi ezishisayo nezinguzungu zeqhwa. Umlando wesintu mude ngokwanele ukuthi sikwazi ukuzwa inkathi yokugcina yeqhwa. Okubuye kudlale indima ebaluleke kakhulu emlandweni wethu ekwandiseni kwethu inani labantu emhlabeni wonke. Esinye salezi zigigaba kwakungangabazeki ukuthi ukufika kwabantu ezwenikazi laseMelika.

Futhi yilokho Kunemibono eminingi yokuthi abantu bafika kanjani eMelika. Kuzo zonke, okunye okunengqondo kakhulu futhi okufakazelwe ukuthi bawele i "Beringia Bridge". Eyaziwa nangokuthi iBeringia nje. Umbuthano wonke obomvu osesithombeni ukhombisa ibhuloho elikhulu elivela eminyakeni engama-40.000 eyedlule. Kubalwa lokho umuntu angayiwela eminyakeni engama-20.000 XNUMX edlule ehamba, ngenkathi ulwandle lwehle ngamamitha ayi-120.

Yayinjani iplanethi yethu ngaleso sikhathi?

Iqhwa lalimboze indawo enkulu. Cishe kathathu ngaphezu kwesilinganiso samanje. Ukushisa okumaphakathi kweplanethi yethu bekuphansi ngo-10ºC kunesilinganiso samanje esingu-15ºC. IBeringia Bridge, okuyingxenye ephawulwe ngombuthano obomvu, yakha indlela yokuwela womabili la mazwekazi. Ezikhathini zeqhwa, izinga lolwandle lehla. Ngokulandelayo, izindawo eziwuketshezi ziyaqina. Njengoba siphawule, izinguzunga zeqhwa zazinkulu kakhulu. Futhi ngempucuko eyimizulane, kwakuyisango lokungena ezweni elisha.

Badabula iNortheast Asia, iRussia yanamuhla, bedlula eBeringia Bridge, iBering Sea yamanje, bafika eAmerican Northwest, i-Alaska yanamuhla. Izimpahla ezivela kokhokho bethu zitholakele, okujwayelekile ngokwesiko ababenalo. Izitsha ezifanayo, zensiza efanayo, ezisikiwe futhi zenziwa ngendlela efanayo.

Ukuphela kwesikhathi seqhwa

Eminyakeni engama-5.000 XNUMX kamuva, cishe eminyakeni eyi-15.000 edlule, kwaphela isikhathi seqhwa. Ngokungazelelwe, izinga lokushisa lakhuphuka eminyakeni eyi-1 kuya kwengu-3 elandelayo. Ngokwamarekhodi e-paleoclimatologists, ongatadisha ushintsho esimweni sezulu seminyaka eyi-125.000 edlule eqhweni ngokusebenza kahle okukhulu. Kanjalo ngendlela ngenxa yenkululeko ye-CO2 ebigcinwe e-Antarctica, njengoba izifundo zakamuva kanye nocwaningo lubonisa. I-Barcelona Institute of Environmental Sciences and Technologies ibambe iqhaza kulokhu.

Iplanethi yaqala ukuzimisa kabusha. Abazulazuli bethu abanesibindi befuna ukusinda, baqhubeka nokuhamba besuka eNyakatho baye eNingizimu kulo lonke elaseMelika. Izinguzunga zeqhwa zaqala ukwehla, ulwandle lwalukhuphuka futhi, futhi ngalo, indawo lapho womabili amazwekazi avalwa khona kusukela lapho. Kwaze kwaba yiminyaka engaphezudlwana nje kwengama-500 edlule, futhi ngokusemthethweni, yomibili impucuko eyayizophinde ihlangane, isikhule ngezindlela ezihlukile.

I-Paleoclimatology. Amasu e-Ice nezimfihlo

I-Paleoclimatologists isebenzisa amasu ahlukene wokuthola ama-paleoclimates. Isibonelo, okuqukethwe kwe-sedimentary, lapho kusuka kumakhemikhali amatshe asezingeni eliphansi noma izidumbu zokuthola izilwane, izimbali, iplankton, impova ... Enye inqubo kungaba i-dendroclimatology, lapho kukhishwa khona ulwazi emasongweni ezihlahla ezifetshisiwe. Amakhorali ukubona i-Tº yezinga eliphezulu elalisolwandle. Amandla we-sedimentary lapho kungagudlulwa khona ulwandle, kukhombisa ushintsho olukhulu lwe-paleoclimatic. Endabeni yeqhwa, okusetshenziswa kakhulu kuvame ukulandelayo:

I-Paleopolen

Phakathi kwamakhasi e-ice akhiwa ahlanganiswa unyaka nonyaka, singathola i-paleopolen. Lokhu kuvumela ukulinganisa ukuthi kwakukhona ziphi izimila phakathi naleyo minyakaNgisho nakuwo kukhona umlotha ovela ekuqhumeni okuthile kwentaba-mlilo.

Umoya

Umoya obhajwe ngendlela yama-microbubbles ungumthombo wolwazi ongaphakathi ngenxa ye- ukwakheka kwayo okusiza ukunquma ukuthi hlobo luni lomkhathi olwalukhona ngaleso sikhathi.

Isotopes ezinzile

Ngokuhwamuka kwamanzi, nomehluko omncane kuma-isotopes azinzile ezigcinwa eqhweni ngenxa yesisindo esingaphansi kwe-hydrogen ne-oxygen, ukuxhumana kuye kwatholakala phakathi kwezikhathi ezahlukahlukene.