Scientists are in general agreement that the warmer conditions we have been experiencing are at least in part the result of a human- induced global warming trend. Some scientists 9 that the changes we are seeing fall within the range of random ( 无规律的 ) variation — some years are cold, others warm, and we have just had an unremarkable string of warm years 10 — but that is becoming an increasingly rare interpretation in the face of continued and increasing warm conditions.