Day 49 - Sea Day - Climate and Currents

After leaving the glaciers, icebergs and fjords behind, we headed towards the equator along the western coast of South America. As expected the South Pacific gradually calmed and the weather quickly changed from biting winter squalls to inviting summer breezes. All was good onboard, but ashore something was drastically different. Most ports were surrounded by deserts. 

One might expect the coastal climates of North and South America to be similar. Both border the Pacific with major mountain ranges inland. They reside in different hemispheres, but that only accounts for the opposing seasons. The difference is most North American coasts receive significant rainfall resulting in lush green environments, while most South American coasts receive little rainfall resulting in vast deserts. Don't take my word for it, check out the greens and browns in Google Maps satellite view. We know this difference exists, but why? There must be another factor drastically affecting rainfall. 

The clue may be in a chart mapping ocean currents. It appears the South American coast receives cold ocean waters from Antarctica. For this reason, the prevailing winds are cool and dry producing little rain along the coast. Insufficient rainfall results in deserts and that makes things challenging. 

Another noteworthy observation can be seen just above Antarctica. The area not only produces strong straight-line currents responsible for Drake's Pass severe weather, but also provides sufficient energy driving most the other ocean currents. We know these currents moderate temperatures and directly affect local climates. We also know civilizations historically thrive in favorable climates. This makes me wonder what would happen if the ocean currents changed or even possibly stopped? Could modern civilizations adapt or would they simply move and colonize elsewhere? Hopefully we never find out.