共用题干New research from NASA scientists suggests emissions of black soot after the way sunlight re- flects off snow.According to a computer simulation,black soot may be responsible for 25 percent of observed global warming over the past century. Soot in the higher latitudes（维度）of the Earth,where ice is more common , absorbs more of the sun's energy and warmth than an icy,white background. Dark-colored black carbon,or soot, absorbs sunlight,while lighter colored ice reflects sunlight.Soot in areas with snow and ice may play an important role in climate change.Also,if snow and ice covered areas begin melting,the warming effect increase,as the soot becomes more con-centrated on the snow surface.“This provides a positive feedback,as glaciers and ice sheets melt, they tend to get even dirtier.”said Dr. James Hansen,a researcher at NASA's Goddard Institute for Space Studies,New York.Hansen found soot's effect on snow albedo（反照率）,which may be contributing to trends to-ward early springs in the Northern Hemisphere,such as thinning Arctic sea ice and melting glac-iers permafrost. Soot also is believed to play a role in changes in the atmosphere above the oceans and land.“Black carbon reduces the amount of energy reflected by snow back into space,thus heating the snow surface more than if there were no black carbon,”Hansen said. Soot's increased absorp-tion of solar energy is especially effective in warming the world's climate.“ This forcing is unusual-ly effective,causing twice as much global warming as a carbon-dioxide forcing of the same magni-tude.”Hansen noted.Hansen cautioned,although the role of soot in altering global climate is substantial,it does not alter the fact that greenhouse gases are the primary cause of climate warming during the past century .Such gases are expected to be the largest climate forcing for the rest of the century.The researchers found that observed warming in the Northern Hemisphere was large in the winter and spring at middle and high latitudes. These observations were coherent with the researchers' climate model situations,which showed some of the largest warming effects occurred when there were heavy snow cover and sufficient sunlight. What is the main cause of climate warming during the past century?A: Soot.B: Snow.C: Greenhouse gases.D:.Wind.
共用题干
New research from NASA scientists suggests emissions of black soot after the way sunlight re- flects off snow.According to a computer simulation,black soot may be responsible for 25 percent of observed global warming over the past century. Soot in the higher latitudes（维度）of the Earth,where ice is more common , absorbs more of the sun's energy and warmth than an icy,white background. Dark-colored black carbon,or soot, absorbs sunlight,while lighter colored ice reflects sunlight.
Soot in areas with snow and ice may play an important role in climate change.Also,if snow and ice covered areas begin melting,the warming effect increase,as the soot becomes more con-centrated on the snow surface.“This provides a positive feedback,as glaciers and ice sheets melt, they tend to get even dirtier.”said Dr. James Hansen,a researcher at NASA's Goddard Institute for Space Studies,New York.
Hansen found soot's effect on snow albedo（反照率）,which may be contributing to trends to-ward early springs in the Northern Hemisphere,such as thinning Arctic sea ice and melting glac-iers permafrost. Soot also is believed to play a role in changes in the atmosphere above the oceans and land.
“Black carbon reduces the amount of energy reflected by snow back into space,thus heating the snow surface more than if there were no black carbon,”Hansen said. Soot's increased absorp-tion of solar energy is especially effective in warming the world's climate.“ This forcing is unusual-ly effective,causing twice as much global warming as a carbon-dioxide forcing of the same magni-tude.”Hansen noted.
Hansen cautioned,although the role of soot in altering global climate is substantial,it does not alter the fact that greenhouse gases are the primary cause of climate warming during the past century .Such gases are expected to be the largest climate forcing for the rest of the century.
The researchers found that observed warming in the Northern Hemisphere was large in the winter and spring at middle and high latitudes. These observations were coherent with the researchers' climate model situations,which showed some of the largest warming effects occurred when there were heavy snow cover and sufficient sunlight.
New research from NASA scientists suggests emissions of black soot after the way sunlight re- flects off snow.According to a computer simulation,black soot may be responsible for 25 percent of observed global warming over the past century. Soot in the higher latitudes（维度）of the Earth,where ice is more common , absorbs more of the sun's energy and warmth than an icy,white background. Dark-colored black carbon,or soot, absorbs sunlight,while lighter colored ice reflects sunlight.
Soot in areas with snow and ice may play an important role in climate change.Also,if snow and ice covered areas begin melting,the warming effect increase,as the soot becomes more con-centrated on the snow surface.“This provides a positive feedback,as glaciers and ice sheets melt, they tend to get even dirtier.”said Dr. James Hansen,a researcher at NASA's Goddard Institute for Space Studies,New York.
Hansen found soot's effect on snow albedo（反照率）,which may be contributing to trends to-ward early springs in the Northern Hemisphere,such as thinning Arctic sea ice and melting glac-iers permafrost. Soot also is believed to play a role in changes in the atmosphere above the oceans and land.
“Black carbon reduces the amount of energy reflected by snow back into space,thus heating the snow surface more than if there were no black carbon,”Hansen said. Soot's increased absorp-tion of solar energy is especially effective in warming the world's climate.“ This forcing is unusual-ly effective,causing twice as much global warming as a carbon-dioxide forcing of the same magni-tude.”Hansen noted.
Hansen cautioned,although the role of soot in altering global climate is substantial,it does not alter the fact that greenhouse gases are the primary cause of climate warming during the past century .Such gases are expected to be the largest climate forcing for the rest of the century.
The researchers found that observed warming in the Northern Hemisphere was large in the winter and spring at middle and high latitudes. These observations were coherent with the researchers' climate model situations,which showed some of the largest warming effects occurred when there were heavy snow cover and sufficient sunlight.
What is the main cause of climate warming during the past century?
A: Soot.
B: Snow.
C: Greenhouse gases.
D:.Wind.
A: Soot.
B: Snow.
C: Greenhouse gases.
D:.Wind.
参考解析
解析：文章第二段最后一句“…while lighter colored ice reflects sunlight.”说浅色的冰反射太阳光，而黑色的煤烟灰并不反射。其他三项在文章一、二段都有提到，故本题选C。
根据第五段首句“Black carbon reduces the amount of energy reflected by snow back in-to space, thus heating the snow surface more than if there were no black carbon,”可知，黑炭覆盖的地区有更强烈的加热效果。故本题选B。
第五段中的“This forcing”指的是其前面所说的“Soot's increased absorption of solar energy”。因此本题选B。
根据第六段“…it does not alter the fact that greenhouse gases are the primary cause of climate warming during the past century.”可知，温室气体是上世纪气候变暖的首要原因，故选C。
由最后一段最后一句“…which showed some of the largest warming effects occurred when there were heavy snow cover and sufficient sunlight.”知，部分大规模的温室效应发生在有厚雪覆盖层和阳光强烈的地方。故本题选C。
根据第五段首句“Black carbon reduces the amount of energy reflected by snow back in-to space, thus heating the snow surface more than if there were no black carbon,”可知，黑炭覆盖的地区有更强烈的加热效果。故本题选B。
第五段中的“This forcing”指的是其前面所说的“Soot's increased absorption of solar energy”。因此本题选B。
根据第六段“…it does not alter the fact that greenhouse gases are the primary cause of climate warming during the past century.”可知，温室气体是上世纪气候变暖的首要原因，故选C。
由最后一段最后一句“…which showed some of the largest warming effects occurred when there were heavy snow cover and sufficient sunlight.”知，部分大规模的温室效应发生在有厚雪覆盖层和阳光强烈的地方。故本题选C。