NATURE: "Moderate global warming does not rule out extreme global climate outcomes"

For droughts in global key breadbasket regions, precipitation extremes over highly populated areas and fire weather extremes across forests, global climatic impact-drivers at 2 °C of global warming may turn out to be much more extreme than model-averaged projections at 3 °C or 4 °C warming. We derive these results by identifying sector-specific, spatially consistent potential high- and low-impact global climate outcomes through spatially averaging projected sector-relevant climatic impact-drivers across key global regions. 

In this study they are looking at the weather extremes at 2° and comparing these against the averages projected for 3° and 4°.

So for example, at 2° forests are still growing lots of trees in a specific region but then fire weather hits and you get a major disaster and a high human impact. At the higher temperatures you don't get that forest in that location in the first place, so the impact isn't as much.

Basically the extreme variability of the weather at 2° is bad enough that a still unadapted world gets caught out.