The distribution of seasonal mean temperature anomalies has shifted toward higher temperatures and the range of anomalies has increased. An important change is the emergence of a category of summertime extremely hot outliers, more than three standard deviations (σ) warmer than climatology. This hot extreme, which covered much less than 1% of Earth’s surface in the period of climatology, now typically covers about 10% of the land area.
The point is that it makes sense to look at the whole distribution, but extreme events provide information also.
P.S. Here are some papers by my Columbia colleague Wolfram Schenkler on potential impacts of global warming on agriculture.