Population growth and food shortages.

Thomas Malthus and Ester Boserup theories
Both theories relate food supply with population size, based on the agricultural methods used for food production.
Malthus Theory:

• Published in “The Principle of Population” in 1798
  
• It presents an approach focusing in the population size being determined by the availability of food
  
• Population growth follows a geometric progression and food growth follows an arithmetic one.
  
• When food supply is scarce, population size will adjust to it.
  
• Food production incensement is a slow and difficult process.
  
• It states that controlling population growth is easier than increasing the food supply.

Limitations:

• The theory doesn’t present the possibility of controlling the human birth rate, but establishes a extremely pessimistic approach where organisms of the human population will just die until food supply is enough.
• It doesn’t consider all of the changes that the industrial revolution brought.

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Boserup Theory:

• Presents a model of population in which the size determines the amount of food available.
  
• When there’s stress in relation between food supply and population size, people will always find a way to increase production.
  
• Workforce, machinery and fertilizers are the methods applied to increase food production.

Limitations:

• At first, when population is low, lands are used intermittently, using fallowing (the burning of crops) to make lands more fertile. It is when population increases, that lands are used in a scheduled way. However, this requires more effort in maintaining the land.
• The more maintenance, the more agricultural innovation, but labor increases towards farmers.
• This tends to increase workforce but decrease crop efficiency, a process Ester calls ‘agricultural intensification’.
  
  

Measures of Population Changes

Population change around time by the action of factors such as birth and death rate and migration.

The basic rate for measuring the fluctuations in population are the following:

Crude Birth Rate (CBR)

The number of births per 1000 individuals in a population per year.

Number of births x 1000

population size

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Crude Death Rate (CDR)

The number of deaths per 1000 individuals in a population per year.

Number of deaths x 1000

population size

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Natural Increase Rate

NIR = (CBR - CDR) / 10

Doesn’t consider immigration and emigration.

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Doubling time

The time in years it takes a population to double its size.

Doubling time = 70 / NIR

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Total Fertility Rate (TFR)

It is the average number of children that each woman has over her life time. It shows the potential of population change.

• A TFR > 2.0 results in a population increase
• A TFR < 2.0 results in a population decrease
• A TFR = 2.0 results in a stable population

In developing countries, the fertility rate is usually higher than in MEDC’s

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Humans impact on the environment is not just given out by its growth, but also by resource use and pollution. It’s impact is affecter by:

• It’s affected by the amount of wealth
• Resource desire
• Resource need

Individuals in a population, specially in a human population, interact with the environment in different ways. We cannot generalize for all the organisms within a population.

Wait for a detailed list of identification of resource use and waste profiles in a further post.

Human Populations Around The World

As we have talked before, the resources of Earth are unequally shared between the organisms of human population. Of course all of these is influenced by the three spheres (social, economical and environmental)

Human Development Index

Adopted by the UN Development Programme as a measure of the well-being of a country.

Combines measurements of:

• Education
• Life expectance
• Standards of living
• Income
• GDP per capita (Gross Domestic Product)

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Countries might also classified based on their industrial development and GDP

MEDCs (used by modern geographers to specifically describe the status of the countries referred to: more economically developed)

• industrialized nations
• rich population small poverty
• high level of resource use per capita
• relatively low population growth rates

LEDCs  (less economically developed)

• less industrialized 
• natural capital unprocessed
• lower GDP and poverty rates
• Large population sector with low standard of living
• High population growth rates

Human Population Dynamics

A very interesting topic. How much does the human population can reach? Which is our carrying capacity?

Different opinions were shared in class. Some said that we had already past our carrying capacity for more than 4 billion organisms. Others said that we are reaching it already. The odd thing was that non of us though we have too much time before we reached our carrying capacity (K)

We have to take into account that in contrast to the other species, we have created a very complex economic system that maintains our society in order and measures the “power” of each entity. This directly affect the dynamics of the our population by stating the repartition of resources and define relationship between entities.

In order to establish an equal share of resources for each organism the population would have to decrease. This is because , even if the global economic system changes its standards, there isn’t enough resources to maintain the actual 6 billion human population.

A simulation of the human population dynamics can be found in this webpage www.breathingearth.net It’s pretty interesting.

Sustainable Yield in Deserts

Sustainability a wide spread term in the last decades. Economists, politicians, scientists and  businessmen are using it for everything. It is really a fashion nowadays. We must understand its real value and its real importance. A sustainable development is needed if we want to maintain the equilibrium of the world, respecting its carrying capacity. 
Sustainable yield is the the natural income that can be exploited each year without getting rid of the resources. Sustainable yield is different from one ecosystem to another. We’ll work with sustainable yield in deserts.
Specifications.
We must considered that resources in desert biomes are very scarce. The levels of precipitation are less than 15 cm a year. The diversity of desert’s flora is relatively low compared to other biomes. Contrary to the common belief the actual fauna of deserts is very rich and its concentrated in certain areas. The resources of deserts around the world differ from one and other. We can find oil and other fossil fuels in some deserts, minerals, and species richness.
In order to measure, and thus manage sustainable yield, we must establish space and time parameters. This will help us to know how much we have and how much we can use.
Useful indicators had been developed in order to maintain track of the advances in sustainable development. Some examples of this indicators can be found here, the Finland's sustainable development indicators:

• Human Development Index
• Greenhouse gas emissions
• Total energy consumption
• Use of renewable energy sources
• Energy and natural resource consumption in relation to economic growth
• Environmental loading in ration to economic growth

It is important to notice that not just because we are respecting the maximum sustainable yield (MSY) of a certain system, the resources will be endless. There are a lot of variations and factors that affect a system. A pretty good example of this is the chaotic situation of West Coast groundfish fishery in the United States, explained deeply here.
This is another thing in which indicators come handy and it’s the point where the management enters into the picture.
Links.
http://www.csgc.ucsd.edu/NEWSROOM/NEWSRELEASES/Carmel_Finley.html
http://www.ymparisto.fi/download.asp?contentid=92350&lan=en

What a CLOUD!!

Another rollin' web page shared by Mr. Mendez www.wordle.net
Enter any text: blog entry, definitions, newspaper article, an essay, and keep rollin'
Be creative and find cool uses to it.
The final result a cloud with the most used words.

Example: definitions of SUSTAINABILITY shared by the class

CLOUD:

Sustainability definition's cloud

Defining Sustainability

In simple words: sustainability is to endure. To exist for a long period of time. If you ask me, sustainability is “the responsible manage of resources that work towards using them while maintaining an equilibrium.”

Introduced in an actual context.
Sustainability is a term that has gained importance in the social world’s context because the arise of concern about the actual Eath’s natural capacity to sustain human life as it is know. That’s why the concept, in means of development, has been defined as: “sustainable development is development that meets the needs of the present without compromising the ability of future generations to meet their own needs.”

As a social issue, sustainability enters in means of maintaining the resources for future generation. We must understand that for the world natural equilibrium to be maintained, we need to start taking greater conscience about damage we are making to the environment and how we are wearing down its sustainability. That’s why society and specific institutions are working to create policies for the regulation of the human activities that act against sustainability.

In an economic context. The concept of sustainable yield enters into the picture. It is the increase of natural capital. The natural income that can be exploited each year without getting rid of it. MSY (maximum sustainable yield) is based on this last idea.

It’s equal to
-(The total biomass or energy at a time) T1 – (total biomass of energy at a time) T
-Annual growth and recruitment – annual death and emigration.

A few points to achieving a sustainable way of living:

• To control the exploitation of natural resources.
  
• To look for alternative practices that help prevent a loss of equilibrium.
  
• Understand the entire human society structure and the economic system as part of the global environmental system

Sustainability is involved in three different spheres. Each one of the spheres functions as an individual particle, but at the same time are affected by the others.

Natural BANK. Do u get the roll?

As in an economic system scheme, capital is related to all the valuable and useful resources that an entity (private company, NGO, and rollin') could have. The main purpose of an economic system is to produce and distribute (for an later consumption) of goods and services by the use of human and manufactured resources to satisfy people's needs and wants.

In contrast we have the NATURAL SYSTEMS, which have their own form of capital. NATURAL CAPITAL is as valuable than "economic capital". It gather all of the means needed to accomplish all of the ends. NATURAL CAPITAL includes

• the natural resources that have value and those that support life
• the natural processes that take place.

As in the economic system, NATURAL CAPITAL is also intend to produce an income.

e.x.

Photosyntesis ------------------------------> oxygen

water cycle -----------------------------> fresh water

nitrogen cycle -------------------------------> nutrients in the soil

biodiversity --------------------------------> stability, evolution, and rollin'

Natural capital might be classified in:

- renewable - replenishable

- non-renewable - recyclable