Earth Systems Science Prof. Joseph Alcamo Center for Environmental Systems Research University of...

Earth Systems Science

Prof. Joseph Alcamo

Center for Environmental Systems Research

University of Kassel, Germany

Lecture I: Introduction -- Definitions and Driving Forces

Prof. Joseph Alcamo Earth Systems Science


Objectives:

Understanding the basic principles of earth systems science especially as it concerns the global water system, global land resources, and atmospheric change.



Lecture I: Definitions and Driving Forces


The Concept of “Earth System”

Definition: earth system scienceBranch of knowledge dealing with Earth as a whole; study of the sum of

processes operating in the atmosphere, hydrosphere, biosphere, cryosphere, and lithosphere, and their interactions

What is included: earth science (atmospheric sciences, geosciences) plus ”large scale“ biological/ecological sciences.

Definition: earth system:

The various large-scale living and non-living components of the earth, together with their interactions.


The Concept of “System”

Definition of a system: A set of components that interact and function together as a unit.

Characteristics:

• Complexity ≈ Number of components and connections.

• “Open” or “closed” system:A closed system = no mass or energy exchange with its environment (surroundings). With respect to mass, the earth system is almost a closed system. An open system = significant mass or energy exchange with its environment. With respect to energy, the earth system is almost an open system.


Example of an Open System


Solar constant 1350 W/m2

The “Spheres” of

the Earth System


Spheres of the Earth System

• Atmosphere – Gas and aerosol component of the earth system above the lithosphere.

• Lithosphere – Non-living part of the soil environment. • Hydrosphere – Water-related component of the earth system –

groundwater, soil water, lakes, rivers, oceans.• Biosphere – Total living component of the earth system.

Sometimes • Cryosphere – Areas of permanent/predominantly ice and snow.• Ecosphere – Domain of living part of the environment.• Technosphere – Domain of society



9 em2 oc3 lan4 atm

Biogeochemical cycles

Definition: Cycles of elements through the atmosphere, hydrosphere, lithosphere, and biosphere.

Especially important because they make available the critical elements to support life.


Driving Forces of Global Environmental Change

Definition of driving forces: With respect to the earth system, the determinants of environmental changes.




Driving Forces of Global Environmental Change

Proximate Drivers

Emissions to the atmosphere Emissions to the hydrosphere Land use changesSoil degradation

Secondary driver


Secondary driver


Anthropogenic Driving Forces

Secondary Drivers Energy production Agriculture Industry Fishery Tourism Household consumption Transport

Proximate Drivers Emissions to the atmosphere Emissions to the hydrosphere Land use changes Soil degradation

Population Growth Rate


Primary driver



Primary DriversChange in population (growth or shrinkage) Change in economy (growth or shrinkage)

Structural change in the economyTechnological change Societal changes (e.g. Institutions, Law, Governance)


Proximate DriversEmissions to the atmosphere Emissions to the hydrosphere Land use changes Soil degradation

Primary Driver: Population ChangeExponential Growth

© 2006 Population Reference Bureau

Ninth

Eighth

Seventh

Sixth

Fifth

Fourth

Third

Second

First Billion

Number of years to add each billion (year)

All of Human History (1800)

130 (1930)

30 (1960)

15 (1975)

12 (1987)

12 (1999)

14 (2013)

14 (2027)

21 (2048)

Sources: First and second billion: Population Reference Bureau. Third through ninth billion: United Nations, World Population Prospects: The 2004 Revision (medium scenario), 2005. www.prb.org/presentations/gb-poptrends_all.ppt

World Population Growth, in Billions

Basic demographic variables

Rate of natural increase = birth rate - death rate

Birth rate (natality) = births . (%)

1000 people – year

Death rate (mortality) = deaths . (%) 1000 people – year

General fertility rate = births (%)(per 1000 women 1000 women – yearin reproductive years)

Geographic Variability of Demographic Indicators

Birth rate (%/a)

Factors Affecting Birth Rate

• Fertility Rate• Population Pyramid


Total Fertility Rate (births/woman-year)

Fertility Rate• Educational level of

women• Family planning

programs• Changing role of

children within workforce (reduction of child labor)

.Net result: fertility rates higher in developing countries, but decreasing worldwide

Reference:

US Census Bureau. Global Population Profile 2002

Population Pyramid• Number of people of each gender in various age groups


World-wide summary

Population Pyramid• Number of people of each gender in various age groups• Despite decreasing fertility rates, many new parents in developing

countries.

Many women of parenting age.


Source: John W. KimballBiology Textbook

Population: Industrialized and Developing

World Population Growth 1950-2050 Population in billions

World: 7,225,984,32514:50 GMT 12 April, 2014

Population: Industrialized and Developing

Source: United Nations, World Population

Prospects as Assessed in 2012.

Source:UNEP, GEO-5

Demographic Transition

Demographic Transition – Four Stages

Stage Feature Consequences

1 Pre-industrial, large families to support agriculture. Poor nutrition, sanitation (e.g.17th C Eur).

high birth rate, high mortality

2 Early industrial phase. Improved nutrition, sanitation

high birth rate, lower mortality

3 Later industrial phase. Less agriculture, fewer large families needed. Education/prosperity reduces desire for large families (e.g. U.S., Can, Rus.)

lower birth rate,lower mortality

4 Post-industrial. Higher level of prosperity, education. (Dk, Swe)

low birth rate mortality

Demographic Transition – Four Stages

Stage Feature Consequences

1 Pre-industrial, large families to support agriculture. Poor nutrition, sanitation (e.g.17th C Eur).

high birth rate, high mortality

2 Early industrial phase. Improved nutrition, sanitation

high birth rate, lower mortality

3 Later industrial phase. Less agriculture, fewer large families needed. Education/prosperity reduces desire for large families (e.g. U.S., Can, Rus.)

lower birth rate,lower mortality

4 Post-industrial. Higher level of prosperity, education. (Dk, Swe)

low birth rate mortality

Demographic Transition

DDT Campaign

Source: John W. KimballBiology Textbook

Death rate drops faster than birth rate

t 2x = 0.69 r

= 0.69 0.015

= 57.5 yrs

Source: FAO

Growth rate (%/yr)

Population: Urbanization

1950 29%

2010 50%

2050* 66%

* UN, World Urbanization Prospects (2104)

Prof. Joseph Alcamo Introduction to Earth Systems Modeling

Scenarios of Global Population

(UN Revisions 2012)

Low fertility

High

Medium

Medium fertility: converge on 1.85Low: - 0.5High: +0.5

Summary about Global Population Trends

Industrialized countries • Birth rate mortality • Population stabilizing

Developing countries• Fertility decline birth rate decline population growth

slows• But, large population reaching parenting age population

increase first exponential, then linear, then stabilizes or declines

• World population 2014 7.2 B2100 (UN, 2012) 7 to 17 B

Implication of Population Changes on Global Change

Why Worry About Population Changes?

Population trends affect the number of consumers of resources, and

the type and intensity of consumption (secondary drivers) changes in

magnitude and type of greenhouse gas emissions, wastewater

discharges, land requirements (proximate drivers) ...


Another prim driver -- econ

Primary DriversChange in population (growth or shrinkage) Change in economy (growth or shrinkage)

Structural change in the economyTechnological change Societal changes (e.g. Institutions, Law, Governance)


Proximate DriversEmissions to the atmosphere Emissions to the hydrosphere Land use changes Soil degradation

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