# 177 | The Great Dying: How The Colonization Of The Americas Cooled The Planet w/ Alexander Koch

In this episode, I speak with Alexander Koch, lead author of the recently-released 'Earth system impacts of the European arrival and Great Dying in the Americas after 1492,' a groundbreaking scientific paper that, as the title suggests, explores the dramatic global climatological changes that resulted from the “Great Dying" of indigenous populations in the Americas after first contact with Europeans in 1492. Alexander and his colleagues’ research has been making the rounds in mainstream media, getting extensive coverage at The Guardian, BBC, The Hill, and numerous other publications.

As Alexander and his colleagues’ research reveals, the "Great Dying” in the Americas ultimately led to the deaths of up to 90 percent of the indigenous population in North and South America, as a result of subsequent waves of infectious diseases and the genocidal actions of the European invaders. In turn, the widespread decline in population led a "7-10 ppm decrease in atmospheric CO2 between 1550 and 1650,” which "is the largest pre-industrial change in CO2 over the past 2,000 years.”* The average surface air temperatures dropped by 0.15°C globally, resulting in what has been defined as the coldest period during what has been described as the "Little Ice Age,”** which extended from about 1300 to 1850. I ask Alexander to elaborate on the details of this research, including how he and his colleagues were able to more accurately estimate the population density in the Pre-Colonial Americas, how many died as a result of contact with Europeans, and how this directly contributed to a shift in global temperatures and carbon output during that timeframe. We also fit the findings of this research within the context our contemporary understanding of the human impact on the global climate system in our present time, and how this research reframes our understandings of when the Anthropocene, “the human epoch,” initially began. We discuss this and more in this episode.

Alexander Koch is currently pursuing his PhD at University College London (UCL), which includes research combining the fields of climate modeling, historical geography and tropical ecology. Along with his colleagues Chris Brierley, Mark M. Maslin, Simon L. Lewis in the Department of Geography at UCL, Alexander is the co-author of the paper 'Earth system impacts of the European arrival and Great Dying in the Americas after 1492,’ the findings of which are discussed in this episode. 

*Source: http://bit.ly/2EfRlU7

**Source: http://bit.ly/2GMHCbC

Episode Notes:

- Read the paper 'Earth system impacts of the European arrival and Great Dying in the Americas after 1492’ at Science Direct: http://bit.ly/2EfRlU7

- Read the summary of Alexander and his colleagues research in 'European colonisation of the Americas killed 10% of world population and caused global cooling' published at The Conversation: http://bit.ly/2U9apds

- Mark M. Maslin and Simon L. Lewis is the author of ‘The Human Planet: How We Created The Anthropocene,’ which expands upon the implications of the findings in this research: http://bit.ly/2GPv1or

- The song featured in this episode is “Shred You To Bits (feat. Shigeto)” by The Gaslamp Killer from the album Instrumentalepathy.