[单选题]（ ）是指可能发生事故，并能造成人员重大伤亡，设备系统造成重大损失的生产现场。
A.危害点
B.危险点
C.危险作业
D.超点作业

Human beings have little direct control over the volume of water in the atmosphere. But we produce other greenhouse gases that intensify the effect. The IPCC estimates that rising CO₂ emissions, mostly from burning fossil fuels, account for about 60 percent of the warming observed since 1850, Carbon dioxide concentration has been increasing by about 0.3 percent a year, and it is now about 30 percent higher than it was before the industrial revolution.
2. The relentless accumulation of greenhouse gases has led the IPCC to project that in the next hundred years average global temperatures will rise by 1 to 3.5 degrees C. That may not
seem like much. Yet the "little ice age," an anomalous cold snap that peaked from 1570 to 1730 and forced European farmers to abandon their fields, was caused by a change of only half a degree.
3.