Alexander Koch

Alexander Koch

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Alexander Koch

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Start Year

2014 (Cohort 1)

Research interests:
Hobbies and interests:

PhD Project
PhD Title

A interdisciplinary modelling approach to estimate the impact of the Columbian depopulation on climate and atmospheric CO2

Research Theme

Earth, Atmosphere and Ocean Processes

Primary Supervisor
Primary Institution


Secondary Supervisor
Secondary Institution



The 7-10 ppm decrease in atmospheric CO2 between 1550 and 1650 is the largest pre-industrial change in CO2 over the past 2,000 years. Natural forcing and natural feedback mechanisms appear not to explain either the full magnitude or the short time period of the CO2 drop. Recent studies therefore suggest that the collapse of the indigenous Meso- and South American population after 1492 and land cover change due to near-cessation of farming thereafter contributed significantly to decreasing CO2 concentrations. Uncertainties in population dynamics and land use patterns prevented climate modelling efforts so far from adequately resolving the magnitude of anthropogenic influence on the CO2 anomaly. This PhD will bridge the gaps between climate modelling, archaeology and tropical vegetation science by combining updated regional population estimates, land use practices and ecological feedbacks on farming abandonment to improve an anthropogenic land cover change dataset (HYDE 3.1). This will then be used to force an Earth System model (HadGEM2-ES) to model carbon fluxes and climatic feedbacks from the Columbian depopulation. The results of this modelling study will contribute to efforts in dating the beginning of the Anthropocene by determining the degree of anthropogenic contribution on pre-industrial variations in the carbon budget and climate.

Policy Impact
Background Reading


Conferences and Workshops
  • Palaeolunchtime seminar. Talk
  • PAGES 2017. Talk

Willis Towers Watson, supervised by Mr Geoffrey Saville. 01/03/2017 – 30/05/2017.

Social Links
University Departmental Website:

Personal Website:





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