DJF MAM JJA SON Measured warming and cooling over the last 20 years Temperature trends (K) over 1993-2012 -3 -2 -1 -0.5 0 0.5 1 2 3 DJF MAM JJA SON Measured warming and cooling over the last 43 years Temperature trends (K) over 1970-2012 -3 -2 -1 -0.5 0 0.5 1 2 3 DJF MAM JJA SON Measured warming and cooling over the last 100 years Temperature trends (K) over 1913-2012 -3 -2 -1 -0.5 0 0.5 1 2 3