Man - made climate change is not a new phenomenon but until now scientists were unsure as to when it first started to take effect . Now new research suggests that warming in land areas and tropical oceans in the Northern Hemisphere has been going on for 180 years . This suggests that warming began during the early stages of the Industrial Revolution much earlier than scientists expected . Most climate records of the past 2 000 years have focused on land records rather than marine ones . However these land records do not account for the importance of oceans in determining the pace of climate change A team of researchers from Australian National University ( ANU ) in Canberra created detailed reconstructions of climate spanning the past 500 years to identify when the warming trend really began They examined natural records of climate variations across the world s oceans . and continents . These included climate histories preserved in corals cave decorations tree rings and ice cores The researchers also analyzed thousands of years of climate model simulations . redictions about uture weather in 21 cteses These included 20 cities that have al The team also looked at Winter Olympics .athere the 2022 WinterBeiing, China, where thOlympics will take place.was 2014when Sctt's teamfirstreported findingnq that "it would be dfficult toimagine recenthost cities sccesstsfullydelvering1 he diverse Olvmpics Gomes.exclusively on natural ice andceand snow'. Theywould need tosupplement (增补) MotherNature's white snow withariallyl (人为地) made snow. That can be done，butitiscostly and does not olways spp thequantity andquality of snow that gold-medal-class athletes expect.Studies haveshown that releases ofgreeenhouse gases in recent yers haveplayed a big ro: in warming the planet.. SoSott's group analyzed two scenarioscenarios (情境)In one,they assumed releases ofthose gases would continue to grow asas theyhave been in recentvvears. Then， theycalculated how February temperatureoute alobe would change by 2050.across the globeThey would ikely rise by 2.6 degreesCeisius. That'sc:ompared to those beforethendusrial Revolution, whenreeleases ofgreenhouse gases1first started to climb. B)2080，those temperatures wcwould likely riseby 4.3 degrees '; Celsius.The team also loked at what wouldhappen if governmenents around the world cutgreernhouse-gas releases. Thentemperatures miglaht rise by only 1.6 degreesCelslus by 2050. After that, they couldhold steady at 1.6 degree; Celsius above thelong-term average--even as l(late as2080. However，noted Scott，whethercountries could achieve that WasIndeed, he said,keeping releases of thosegasesfrom climbing was "an ambitioustarget"Even f nations promised to cutreleses of these, they sil might noththeir goal.Under the make-no-change senrrinine of the host sites'et cites will be too warm for thegomes by 2050. Those indude sochil ineRussia，and the Cpine cities of Grenoble inFrance and Garmisch-PartenkircheninGermany .The nummber will increase to 13aties by 2080. Cuting down crent ratesof greenhouse-gaseleases would help.But even then, eight former WinterOlympics sites scill will be unable to host thegomes by 2050. Nine wont qulifyby2080.(1) We can learn from the text that artificially made snow_A. is costly but of good qualityB. is favored even by gold-medal-class athletesC is not a satisfactory supplement to natural snow for the Winter OlympicsD. can help meet the quantity requirements of snow for the Winter Olympics(2) If releases of greenhouse gases are not controlled , February temperatures will rise by__Celsius by 2050 compared toA.1.6degree Celsius by 2050 compared to those before the Industrial RevolutionB.1.7 degrees Celsius by 2080 compared to those of 2050C.2.6 degrees Celsius by 2080 compared to those before the Industrial RevolutionD. 4.3 degrees Celsius by 2080 compared to those of 2050(3) What is Scot's attitude towards governments reaching the target for cutting greenhouse- gas releases?A. Doubtful.B. Uncaring.C. Respectful.D. Hopeful.(4) Under the make-changes how man, cities will be too hot to host the Winter Olympics by 2050?一A. Five .B. Eight.C. Nine.D. Thirteen.