Climate change is hard to measure because it is noisy data. Decades of data provide trends. Daily fluctuations provide noise. The trend is for 0.16 C increase per decade, which is a small enough number to miss in short term data. Short term data variations can also hide spikes as noise. There’s reason to believe that the trend lines is about to accelerate. If so, arctic warming could increase one degree by 2020, a twelve-fold increase in a region where permafrost is already melting fast enough to create explosive methane craters.