Climatologist: Global warming is affecting snowfall throughout the

IMO - D

POE

(A) The percentages he cites will continue to decrease at a linear rate. - Even if it does not continue to decrease linearly still does not affect the conclusion - Eliminate

(B) Global warming will cease to be a factor in the state’s snowfall yields over the next 20-30 years. - Irrelevant to the conclusion-Eliminate

(C) Global warming is not the only factor affecting the state’s snowfall yields over the past decade. - Conclusion is about the global warming only any alternative plan is straight away weakener for the assumption question. - Eliminate

(D) The amount of precipitation in the state in 2009 was not significantly greater than it had been in 2004. - Correct

(E) The volume of rainfall, the other primary form of precipitation in the state, was not higher in 2004 than it was in 2009. - We are only concerned with the snow in the question. - Eliminate

­Percentage decrease doesn't always mean that the overall value is decreasing.

For "At this rate" trend to be true, the absolute value of snow precipitation in 2009 should be less than in 2004, otherwise it will break the conclusion. For example, let's say there was 100mm precipitation overall in 2004. This means 60% or 60mm was in the form of snow. Now, for 2009, let's consider two cases of precipitation: 1) 150mm and 2) 75mm. In the 1st case, 42% precipitation was in snow form, which is equal to 63mm. This is greater than 60mm snow precipitation in 2004, meaning that the author's conclusion about possible no snowfall in the next 20-30 years doesn't hold true. However, in the 2nd case, snow precipitation would be ~32mm, less than in 2004. Therefore, in order to not break author's conclusion, the 2009 snow precipitation should not be significantly greater than in 2004.

Hope this is clear.­