According to the text, the phenomenon of climate change is

Leia o texto para responder às questões de números 49 e 50.

Food Supply Worries ofan Agricultural Scientist — Climate Change

People involved in world agriculture have no patience with the supposed “debate” about climate change. We are already seeing the effects, and the projections for the future are not encouraging.

The most troubling feature of this phenomenon (and one that occurs even if you don't believe that it is human-driven) is that we are facing increasing variation in climatic events. The yearly changes in average temperature or even annual rainfall may not be dramatic, but what we are anticipating is that there will be more extreme weather events.

(www.sustainablog.org/category/climate-change/01.10.2009. Adaptado)