Almost 40,000 people in the United States developed West Nile virus last year and 1,549 died because of it. Compare that to 1999, the first year the disease was seen in North America, when only 62 people were reported infected.

We’re not used to thinking of ourselves as animals. But as Jason Samson sees it, climate is as important in shaping the distribution and movement of humans as it is in other animals. The McGill-trained ecologist and fellow researchers have been using modeling techniques similar to those used to define the ecological niche for plant and animal species to explore the correlation between climate patterns and population growth in the contiguous United States between 1900-2000. And what they discovered was a pronounced population shift away from areas within the U.S. with cool and seasonal climates, towards those areas that are warmer and drier year-round, and they found that this was the case even when it meant moving further away from agricultural lands.