Warming
So how will life in South America likely change if these predictions are accurate? There has always been natural variability, with some places and some years warmer or cooler than average. In general, however, summers will get hotter, not only because of higher temperatures, but also because humidities will increase. A warming trend on top of natural variability means that temperatures will cross today’s heat danger thresholds more often.
Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Figure 10.19 (b), Cambridge University Press.
For example, the 2003 European heat wave that killed 35,000 people was a combination of global warming and extreme natural variability and could not have happened without both. Models predict that in many places, an extreme heat event that we only see once every 20 years today will happen once every 3 years by the middle of this century, and even more frequently by century’s end.
Temperature anomalies during the 2003 European heat wave
