Molecular evidence for human population change associated with climate events in the Maya lowlands

Abstract. Wildfires are by far the largest contributor to global biomass burning and constitute a large global source of atmospheric traces gases and aerosols. Such emissions have a considerable impact on air quality and constitute a major health hazard. Biomass burning also influences the radiative balance of the atmosphere and is thus not only of societal, but also of significant scientific interest. There is a common perception that climate change will lead to an increase in emissions as hot and dry weather events that promote wildfire will become more common. However, even though a few studies have found that the inclusion of CO2 fertilization of photosynthesis and changes in human population patterns will tend to somewhat lower predictions of future wildfire emissions, no such study has included full ensemble ranges of both climate predictions and population projections, including the effect of different degrees of urbanisation. Here, we present a series of 124 simulations with the LPJ-GUESS-SIMFIRE global dynamic vegetation – wildfire model, including a semi-empirical formulation for the prediction of burned area based on fire weather, fuel continuity and human population density. The simulations comprise Climate Model Intercomparison Project 5 (CMIP5) climate predictions from eight Earth system models using two Representative Concentration Pathways (RCPs) and five scenarios of future human population density based on the series of Shared Socioeconomic Pathways (SSPs), sensitivity tests for the effect of climate and CO2, as well as a sensitivity analysis using two alternative parameterisations of the semi-empirical burned-area model. Contrary to previous work, we find no clear future trend of global wildfire emissions for the moderate emissions and climate change scenario based on the RCP 4.5. Only historical population change introduces a decline by around 15 % since 1900. Future emissions could either increase for low population growth and fast urbanisation, or continue to decline for high population growth and slow urbanisation. Only for high future climate change (RCP8.5), wildfire emissions start to rise again after ca. 2020 but are unlikely to reach the levels of 1900 by the end of the 21st century. We find that climate warming will generally increase the risk of fire, but that this is only one of several equally important factors driving future levels of wildfire emissions, which include population change, CO2 fertilisation causing woody thickening, increased productivity and fuel load, and faster litter turnover in a warmer climate.

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Did pre-Columbian populations of the Amazonian biome reach carrying capacity during the Late Holocene?

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2019.0715 ◽

2020 ◽

Vol 376 (1816) ◽

pp. 20190715 ◽

Cited By ~ 2

Author(s):

Manuel Arroyo-Kalin ◽

Philip Riris

Keyword(s):

Carrying Capacity ◽

Human Population ◽

Late Holocene ◽

Amazon Basin ◽

Population Change ◽

Relative Population ◽

Robust Model ◽

Recent Developments ◽

European Colonization ◽

Procurement Strategies

The increasingly better-known archaeological record of the Amazon basin, the Orinoco basin and the Guianas both questions the long-standing premise of a pristine tropical rainforest environment and also provides evidence for major biome-scale cultural and technological transitions prior to European colonization. Associated changes in pre-Columbian human population size and density, however, are poorly known and often estimated on the basis of unreliable assumptions and guesswork. Drawing on recent developments in the aggregate analysis of large radiocarbon databases, here we present and examine different proxies for relative population change between 1050 BC and AD 1500 within this broad region. By using a robust model testing approach, our analyses document that the growth of pre-Columbian human population over the 1700 years prior to European colonization adheres to a logistic model of demographic growth. This suggests that, at an aggregate level, these pre-Columbian populations had potentially reached carrying capacity (however high) before the onset of European colonization. Our analyses also demonstrate that this aggregate scenario shows considerable variability when projected geographically, highlighting significant gaps in archaeological knowledge yet also providing important insights into the resilience of past human food procurement strategies. By offering a new understanding of biome-wide pre-Columbian demographic trends based on empirical evidence, our analysis hopes to unfetter novel perspectives on demic expansions, language diversification trajectories and subsistence intensification processes in the Amazonian biome during the late Holocene. This article is part of the theme issue ‘Cross-disciplinary approaches to prehistoric demography’.

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Impact of global change on future Ebola emergence and epidemic potential in Africa

10.1101/206169 ◽

2017 ◽

Cited By ~ 3

Author(s):

D. W. Redding ◽

P. M. Atkinson ◽

A. A. Cunningham ◽

G. Lo Iacono ◽

L. M. Moses ◽

...

Keyword(s):

Land Use ◽

Human Population ◽

Ebola Virus ◽

Population Change ◽

Economic Impacts ◽

Zoonotic Diseases ◽

Future Scenarios ◽

Major Health ◽

Health Infrastructure ◽

Future Risk

ABSTRACTAnimal-borne or zoonotic human diseases (e.g., SARS, Rabies) represent major health and economic burdens throughout the world, disproportionately impacting poor communities. In 2013-2016, an outbreak of the Ebola virus disease (EVD), a zoonotic disease spread from animal reservoirs caused by the Zaire Ebola virus (EBOV), infected approximately 30,000 people, causing considerable negative social and economic impacts in an unexpected geographical location(Sierra Leone, Guinea, and Liberia). It is not known whether the spatial distribution of this outbreak and unprecedented severity was precipitated by environmental changes and, if so, which areas might be at risk in the future. To better address the major health and economic impacts of zoonotic diseases we develop a system-dynamics approach to capture the impact of future climate, land use and human population change on Ebola (EVD). We create future risk maps for affected areas and predict between a 1.75-3.2 fold increase in EVD outbreaks per year by 2070. While the best case future scenarios we test saw a reduction in the likelihood of epidemics, other future scenarios with high human population growth and low rates of socioeconomic development saw a fourfold increase in the risk of epidemics occurring and almost 50% increase in the risk of catastrophic epidemics. As well as helping to target where health infrastructure might be further developed or vaccines best deployed, our modelling framework can be used to target global interventions and forecast risk for many other zoonotic diseases.Significance StatementDespite the severe health and economic impacts of outbreaks of diseases like SARS or Zika, there has been surprisingly little progress in predicting where and when human infectious disease outbreaks will occur next. By modelling the impacts of future climate, land use and human population change on one particular disease Ebola, we develop future risk maps for the affected areas and predict 1.7-3.2 times as many human Ebola outbreaks per year by 2070, and a 50% increase in the chance that these outbreaks will become epidemics. As well as helping to target where health infrastructure might be further developed or vaccines deployed, our approach can also be used to target actions and predict risk hotspots for many other infectious diseases.

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Did pre-Columbian populations of the Amazonian biome reach carrying capacity during the Late Holocene?

10.31235/osf.io/ws8et ◽

2020 ◽

Author(s):

Manuel Arroyo-Kalin ◽

Philip Riris

Keyword(s):

Carrying Capacity ◽

Human Population ◽

Late Holocene ◽

Amazon Basin ◽

Population Change ◽

Relative Population ◽

Robust Model ◽

Recent Developments ◽

Procurement Strategies ◽

Broad Region

The increasingly better-known archaeological record of the Amazon basin, the Orinoco basin, and the Guianas both questions the long-standing premise of a pristine tropical rainforest environment and also provides evidence for major biome-scale cultural and technological transitions prior to European colonisation. Associated changes in pre-Columbian human population size and density, however, are poorly known and often estimated on the basis of unreliable assumptions and guesswork. Drawing on recent developments in the aggregate analysis of large radiocarbon databases, here we present and examine different proxies for relative population change between 1050 BC and AD 1500 within this broad region. By using a robust model-testing approach, our analyses document that the growth of pre-Columbian human population over the 1,700 years prior to European colonisation adheres to a logistic model of demographic growth. This suggests that, at an aggregate level, these pre-Columbian populations had likely reached carrying capacity (however high) before the onset of European colonisation. Our analyses also demonstrate that this aggregate scenario shows considerable variability when projected geographically, which bears on our overall understanding of the resilience of past human food procurement strategies. Lastly, our results provide important insights into pre-Columbian demographic trends and offer novel perspectives on demic expansions, language diversification, and subsistence intensification in the Amazonian biome during the late Holocene.

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Modelling human population change on Easter Island far-from-equilibrium

Quaternary International ◽

10.1016/j.quaint.2007.09.019 ◽

2008 ◽

Vol 184 (1) ◽

pp. 150-165 ◽

Cited By ~ 10

Author(s):

Anthony Cole ◽

John Flenley

Keyword(s):

Human Population ◽

Population Change ◽

Easter Island ◽

Far From Equilibrium

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The influence of human population change and aquatic invasive species establishment on future recreational fishing activities to the Canadian portion of the Laurentian Great Lakes

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/cjfas-2020-0159 ◽

2020 ◽

Author(s):

Len M. Hunt ◽

Daniel J. Phaneuf ◽

Joshua K. Abbott ◽

Eli P. Fenichel ◽

Jennifer A. Rodgers ◽

...

Keyword(s):

Invasive Species ◽

Great Lakes ◽

Human Population ◽

Population Change ◽

Aquatic Invasive Species ◽

Laurentian Great Lakes ◽

Ctenopharyngodon Idella ◽

Recreational Fishing ◽

Potential Growth ◽

Fishing Activity

We project how human population change (2018 to 2046) and aquatic invasive species (AIS) establishment events of bigheaded carps (Hypopthalmichthys spp.) and grass carp (Ctenopharyngodon idella) might combine to affect future Canadian recreational fishing activity for the Laurentian Great Lakes. Human population change is expected to affect the total number of fishing trips (increase of about 143 000 trips or 11.4%) more than any of the AIS establishment events (maximum decrease of about 44 000 trips or 3.5%). The projected 11.4% increase to the number of fishing trips from human population change, however, lags the 38% projected increase to Ontario, Canada’s population from 2018 to 2046. Increasing urbanization and an aging population, which are associated with reduced rates of fishing participation, were responsible for this difference. The combined effects of human population change and AIS establishment illustrate the importance of accounting for human population change as it reverses the conclusions and results in a projected net increase of between 92 000 and 125 000 in the number of fishing trips. The combined model also identifies potential growth areas for fishing such as shore fishing by urbanites on the western portion of Lake Ontario.

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Climate, CO<sub>2</sub> and human population impacts on global wildfire emissions

Biogeosciences ◽

10.5194/bg-13-267-2016 ◽

2016 ◽

Vol 13 (1) ◽

pp. 267-282 ◽

Cited By ~ 50

Author(s):

W. Knorr ◽

L. Jiang ◽

A. Arneth

Keyword(s):

Climate Change ◽

Population Density ◽

Population Growth ◽

Biomass Burning ◽

Human Population ◽

Population Change ◽

Future Climate Change ◽

Burned Area ◽

Human Population Density ◽

Semi Empirical

Abstract. Wildfires are by far the largest contributor to global biomass burning and constitute a large global source of atmospheric traces gases and aerosols. Such emissions have a considerable impact on air quality and constitute a major health hazard. Biomass burning also influences the radiative balance of the atmosphere and is thus not only of societal, but also of significant scientific interest. There is a common perception that climate change will lead to an increase in emissions as hot and dry weather events that promote wildfire will become more common. However, even though a few studies have found that the inclusion of CO2 fertilisation of photosynthesis and changes in human population patterns will tend to somewhat lower predictions of future wildfire emissions, no such study has included full ensemble ranges of both climate predictions and population projections, including the effect of different degrees of urbanisation.Here, we present a series of 124 simulations with the LPJ–GUESS–SIMFIRE global dynamic vegetation–wildfire model, including a semi-empirical formulation for the prediction of burned area based on fire weather, fuel continuity and human population density. The simulations use Climate Model Intercomparison Project 5 (CMIP5) climate predictions from eight Earth system models. These were combined with two Representative Concentration Pathways (RCPs) and five scenarios of future human population density based on the series of Shared Socioeconomic Pathways (SSPs) to assess the sensitivity of emissions to the effect of climate, CO2 and humans. In addition, two alternative parameterisations of the semi-empirical burned-area model were applied. Contrary to previous work, we find no clear future trend of global wildfire emissions for the moderate emissions and climate change scenario based on the RCP 4.5. Only historical population change introduces a decline by around 15 % since 1900. Future emissions could either increase for low population growth and fast urbanisation, or continue to decline for high population growth and slow urbanisation. Only for high future climate change (RCP8.5), wildfire emissions start to rise again after ca. 2020 but are unlikely to reach the levels of 1900 by the end of the 21st century. We find that climate warming will generally increase the risk of fire, but that this is only one of several equally important factors driving future levels of wildfire emissions, which include population change, CO2 fertilisation causing woody thickening, increased productivity and fuel load and faster litter turnover in a warmer climate.

Download Full-text