Huella

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Ecological footprint
The ecological footprint is the amount of land that would be required to provide the resources for a population

The world's ecological footprint (2017) is 2.77 ha per person

Biocapacity is the land available to meet people's demand. The Earth's biocapacity (2017) is 1.6 ha per person.

$$\frac{2.77}{1.6}=1.73 Earths$$

In words, humans are now using resources 1.73 times what the Earth can provide. By 2030 this will grow to about 2 Earths.

The following table shows the footprint/biocapacity for selected countries.



! !Footprint !Biocapacity
 * Australia
 * 7.27
 * 12.64
 * United Arab Emirates
 * 8.95
 * 0.53
 * United States of America
 * 8.04
 * 3.45
 * Russia
 * 5.48
 * 6.96
 * Thailand
 * 2.58
 * 1.22
 * India
 * 1.19
 * 0.43
 * }
 * 1.22
 * India
 * 1.19
 * 0.43
 * }
 * }

I=PAT
As can be seen from above, the footprint is not only dependent on the population, but on the amount of resources used per capita. This can be represented by the (highly) simplified model:

I = PxAxT

where I = Impact, P = Population (size), A = Affluence (consumption of resources per person), T = Technological impact (per unit consumption)

Food Security

 * Food Security : When all people have physical, social, and access to sufficient, safe, and nutritious food for normal growth and development.

Four parts to food security:
 * food availability
 * economic and physical access to food
 * food utilization
 * stability over time

The Second Sustainable Development Goal (SDG2) is to end hunger and malnutrition by the year 2030.

Note from the food security definition, it is not only the amount of food that is important.

Undernourishment

 * Undernourishment : inability to acquire enough food to meet dietary requirements


 * Hunger : chronic undernourishment

The number of people undernourished steadily declined from 811 million in 2005 to 607 million in 2015. However, the number increased to 615 million in 2016. This trend has continued and the number in 2019 was 650 million. That number increased dramatically in 2020 to around 768 million.

The largest percentage of people undernourished is in Africa, but the largest total number of people undernourished is in Asia. Food security has worsened in parts of sub-Saharan Africa, Western Asia, and South-east Asia.

Malnutrition

 * Malnutrition : abnormal condition due to poor nutrition


 * Stunting : Low height for age


 * Wasting : Low weight for height

In 2020, 22% of children under 5 years old were stunted and 6.7% were wasted.

Overweight

 * Overweight : A BMI over 25, but under 30


 * Obesity : A BMI over 30

Here BMI is the body mass index defined as weight (in kg) divided by height (in meters) squared.

Overweight and Obesity is also due to poor nutrition.

Overweight and Obesity have increased since 2004 worldwide. In 2020, 5.7% of children under 5 were over weight and 13% of adults were obese.

Food Prices

 * An important part of food security is price of food


 * Some major factors involved:
 * diversion of crops or farmland to biofuels
 * climate change
 * speculation on commodity markets

Food Loss

 * Over 1/3 of all food produced is lost
 * Food lost occurs throughout the supply chain
 * examples: insufficient refrigeration, poor handling during transport, over-processing

Food Production

 * Three crops - rice, wheat, and corn - make up 60% of world's food energy intake


 * 15 crops make up 90% of world's food energy intake


 * These crops are almost all monoculture

Soil

 * Soil : Complex mixture of eroded rocks, mineral nutrients, decayed organic matter, water, air, and living organisms.


 * Topsoil : The upper part of the soil which contains most of the organic matter and nutrients. This is the part used by crops for growth.

Soil Conservation

 * Soil Erosion is the loss of topsoil due to wind or water. It is a major concern for agriculture.


 * Soil Fertility is the ability of soils to have nutrients, etc. necessary for plant growth


 * Soil Conservation are methods which reduce the amount of soil erosion and prevent reduced soil fertility

Other Environmental Effects of Crop Production

 * Soil salinity is an increase in salt concentration in a soil. Often from over-irrigation.


 * Desertification - land degradation of drylands. Addressed by the UN Convention on Combating Desertification


 * Overuse of fertilizers. This can lead to eutrophication.


 * pesticides can get into the water and cause health problems.


 * Water - desertification, soil salinity, water shortages

Meat Production

 * About one-third of crops goes to feed livestock


 * It takes about 10 kg of grain to produce 1 kg of meat


 * Cattle produce large amounts of methane which causes global warming

Antibiotic Overuse
One major concern in meat production has been overuse of Antibiotics

Antibiotics are drugs which kill bacteria; However, but they have also been found to increase the growth rate of livestock

The major problem from overuse is that it can increase the amount of antibiotic-resistant bacteria resistance in humans

Fisheries
About 20% of the world's protein is from fish.

Unlike other forms of protein, most fish and seafood is harvested from the wild.

Overfishing is now become a serious problem. One-third of all fisheries are at unsustainable levels

In addition to overfishing, some methods used by commercial fishermen are destructive to the environment. Some of these methods:


 * Bottom trawling drags a large net along the bottom, destroying the seafloor


 * Large nets called purse seines can catch unintended animals such as dolphins, turtles, sharks, and sea lions


 * Longlines, which can have as many as 25,000 hooks, can catch dolphins, seabirds, etc.

Aquaculture
About 40 percent of fish and seafood today is from fish farms. Some major problems with aquaculture include:


 * Many farmed fish are carnivores, therefore they have to be fed with wild caught fish


 * Aquaculture can have problems with waste and disease


 * Aquaculture (especially shrimp farms) have had a major impact on mangroves and estuaries

Alternative Agriculture
Some alternative forms of agriculture which can reduce the ecological footprint:


 * Organic Farming


 * Agroforestry - growing crops and trees are the same land


 * Polyculture - multiple crops at same time


 * No-till agriculture


 * Other Sustainable practices: integrated pest management, free range animals, organic fertilizers, soil conservation techniques, drip irrigation

Urbanization
The percent of people living in urban areas has been rapidly increasing. Currently half of all people live in cities.

By 2030, UN-Habitat estimates 60% will live in cities.

In Latin America over 80% live in cities.

26 cities are megacities (> 10 million people), 9 have more than 20 million people

1 billion people live in urban slums

The problem is providing the necessary services to the cities inhabitants. For example, water, sanitation, police, and fire.

Most of the problems come from unplanned growth.

Smart Growth
Smart growth of cities tries to avoid the pitfalls of unplanned growth. It includes:


 * Increase use of bicycles and mass transit systems
 * Reduction in number of vehicles, especially in the city center
 * Planning of services such as water, sewage, solid waste, flood prevention
 * Greening of cities by adding greenspace (parks, wood areas, etc.) and possibly urban gardening areas