Comenius:2009.05: Desertificación

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Preguntas iniciales, tareas, algunas referencias

La desertización (o desertificación) es uno de los principales problemas ambientales del mundo. Su principal síntoma es la degradación de los suelos, y sus causas son esencialmente dos: los cambios en el clima y la actividad humana. El desierto no tiene nada que ver con el calor, sino con la falta de agua. Con respecto al calentamiento global y la desertización es que, si nos basamos en la experiencia, un aumento del CO2 y la temperatura no produciría desertización, sino todo lo contrario; una vegetación exuberante. Las prácticas de regadío incorrectas y la sobre explotación, la deforestación, tala excesiva y la guerra, son considerados factores que causan la desertización, agravada por las evidencias de calentamiento mundial. Los vertidos a los ríos de metales pesados, la deforestación y la contaminación del suelo son algunos de los principales problemas; una de las mayores amenazas son los cambios hidrológicos y las enfermedades derivadas de la contaminación del agua.

Analizar cómo repercute la actividad industrial, agrícola y minera en los diferentes países que modifican los orígenes de los ríos, alteran los mares y muchos de los accidentes geográficos, contaminando las aguas y perjudicando a los ecosistemas. Los vertidos a los ríos de metales pesados, la deforestación y la contaminación del suelo son algunos de los principales problemas; una de las mayores amenazas son los cambios hidrológicos y las enfermedades derivadas de la contaminación del agua. Comparativa de las zonas mundiales más desérticas de forma natural. Y complementar con las zonas en vías de desertización provocas por la actividad humana.

Entender el proceso de Transpiración; Los árboles también almacenan agua y luego la liberan hacia la atmósfera… Causas, procesos naturales y provocados, y consecuencias de la deforestación. Estudiar las consecuencias del avance de los desiertos: hambre, migraciones, fuertes pérdidas económicas, haciendo un estudio comparativo de las zonas más áridas del planeta que son las que mayor riesgo tienen. Consecuencias derivadas de la falta de medicamentos a causa de la desforestación.

Estudiantes Lope de Vega

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E.S.O. 4B: Daniel Jaime, Valle, María RM, Davinia

1st Newsletter Oct 2009 LdV

Our topic is the desertification. This topic is very interesting, because it's one of the principal environmental problems in the world. Eventually it carries to environmental disasters. Its principal symptom is the degradation of the soil. The most important reasons are: the changes in the climate and human activities. There are two types of deserts, a natural desert and other desert formed by human activity. The desert has nothing to do with the heat, but the lack of water.

2nd Newsletter Nov 2009 LdV

We're working together, each group member has a sub topic about desertification, but we need to edit more information at the wiki. We are learning that this environmental problem is very serious. For example: the dry lands make up 41% of the surface on the world. In Asia the most affected area is in Central Asia. In Europe the most affected country is Spain. We want people to learn about this problem and know that it is part of the serious problems we have in the world.

3rd Newsletter Nov 2009 LdV

Desertification refers to the persistent degradation of dryland ecosystems by climatic variations and human activities. It occurs on all continents (except Antarctica) and affects the livelihoods of millions of people, including a large proportion of the poor in drylands.

Desertification poses one of the greatest environmental challenges today and constitutes a major barrier to meeting basic human needs in drylands.

Effectively dealing with desertification will help reduce global poverty, and is essential for meeting the Millennium Development Goals.

The greatest vulnerability is ascribed to sub-Saharan and Central Asian drylands.

In three key regions of Africa:The Sahel, The Horn of Africa and Southeast Africa.

Some 10 to 20% of drylands are already degraded

Based on these rough estimates, about 1–6% of the dryland people live in desertified areas, while a much larger number is under threat from further desertification.

These zones have severe droughts occur on average once every 30 years.


Our conclusions:

Desarrollo del tema

06 Nov 2009: Presentación del grupo 05 - Desertificación


What is desertification?


Desertification refers to the persistent degradation of dryland ecosystems by climatic variations and human activities. It occurs on all continents (except Antarctica) and affects the livelihoods of millions of people, including a large proportion of the poor in drylands.

Desertification occurs as a result of a long-term failure to balance human demand for ecosystem services and the amount the ecosystem can supply.The pressure is increasing on dryland ecosystems for providing services. This increase is attributed to a combination of human factors and climatic factors.

Drylands, occupy 41% of Earth’s land area.



Mapa.jpg----

Drylands include all terrestrial regions where the produDesertification refers to the persistent degradation of dryland ecosystems by climatic variations and human activities. It occurs on all continents (except Antarctica) and affects the livelihoods of millions of people, including a large proportion of the poor in drylands.ction of crops, forage, wood and other ecosystem services are limited by water. Formally, the definition encompasses all lands where the climate is classified as dry subhumid, semiarid, arid or hyper-arid.

Some 10 to 20% of drylands are already degraded



Based on these rough estimates, about 1–6% of the dryland people live in desertified areas, while a much larger number is under threat from further desertification.

The reduction services of the ecosystems


Persistent, substantial reduction in the provision of ecosystem services as a result of water scarcity, intensive use of services, and climate change is a much greater threat in drylands than in non-dryland systems. The projected intensification of freshwater scarcity as a result of climate change will cause greater stresses in drylands. If left unmitigated, these stresses will further exacerbate desertification.

The greatest vulnerability is ascribed to sub-Saharan and Central Asian drylands.

In three key regions of Africa:

  1. The Sahel
  2. The Horn of Africa
  3. Southeast Africa

Sahel.gif Africa1.png Africa4.jpg

These zones have severe droughts occur on average once every 30 years. These droughts triple the number of people exposed to severe water scarcity at least once in every generation, leading to major food and health crises. Some 10 to 20% of drylands are already degraded ====



Based on these rough estimates, about 1–6% of the dryland people live in desertified areas, while a much larger number is under threat from further desertification.

What are the consequences of desertification?


Desertification is caused by a combination of factors that change over time and vary by location. These include indirect factors such as population pressure, socioeconomic and policy factors, and international trade as well as direct factors such as land use patterns and practices and climate-related processes.

These factors lead to decreased land productivity and a downward spiral of degradation and poverty Where conditions permit, dryland populations can avoid degradation by improving their agricultural and grazing practices in a sustainable way.

Schematic Description of Development Pathways in Drylands

Figure1-1.jpg

This is a schematic graphic showing how drylands can be developed in response to changes in key human factors.


Desertificacion affects all categories of ecosystem services:

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· Provisioning sevices such as food, forage, fiber, and fresh water.

· Regutating services such as water purification and climate regulation,

· Cultural services such as recreation and cultural identity.

· Supporting services such as soil conservation.


When faced with desertification, people have responded by either increasingly using other low productivity land for cultivation or by converting more rangeland into cultivated land. Since policies to promote alternative livelihoods are usually not in place, people often migrate to other areas, towards cities or even to other countries.

In many semiarid areas, there is a progressive shift from grassland (land fully covered by grasses) to shrubland (land covered by scattered bushes) that promotes soil erosion by leaving the topsoil exposed to the wind, which can lead to desertification.


Tabla.jpg Desertification refers to the persistent degradation of dryland ecosystems by climatic variations and human activities. It occurs on all continents (except Antarctica) and affects the livelihoods of millions of people, including a large proportion of the poor in drylands.

Is there a link between desertification, global climate change, and biodiversity loss?


Biological diversity, which contributes to many of the services provided to humans by dryland ecosystems, is diminished by desertification. Vegetation and its diversity are instrumental in soil conservation and in the regulation of surface water and local climate. These zones have severe droughts occur on average once every 30 years. Desertification affects global climate change through soil and vegetation losses. Indeed, dryland soils contain a lot of carbon which could be released into the atmosphere as a result of desertification, with significant consequences for the global climate system.

The effect of global climate change on desertification is complex and not yet sufficiently understood. On the one hand, higher temperatures can have a negative impact through increased loss of water from soil and reduced rainfall in drylands. On the other hand, an increase in carbon dioxide in the atmosphere can boost plant growth for certain species. Although climate change may increase aridity and desertification risk in many areas, the consequent effects of biodiversity loss on desertification are difficult to predict.


Biodiversidad.jpg Arido.jpg


What social, economic, and policy factors can contribute to desertification?


Policies leading to an unsustainable use of resources and the lack of adequate infrastructures are major contributors to land degradation. Agriculture can play either a positive or a negative role, depending on how it is managed. Local institutions can contribute to preventing desertification by allowing land users to manage and use ecosystem services more effectively through enhanced access to productive land, capital, labor, and technology.

Policies favoring sedentary farming over nomadic herding can contribute to desertification. The 65% of dryland areas are rangelands that are more suited to sustainable grazing than crop production. Sedentarizing nomads and limiting their movements leads to desertification.

When farmers and herders lose control or long-term security over the land they use, the incentives for maintaining environmentally sustainable practices are lost, and this can greatly contribute to desertification.

Does globalization play a role in desertification?


The process of globalization can either contribute to desertification or help prevent it. Globalization creates stronger links between local, national, sub-regional, regional, and global factors related to desertification. In dryland areas, trade liberalization, macroeconomic reforms, and a focus on raising agricultural and livestock production for exports can sometimes lead to desertification.

How can land use affect desertification?


Desertification refers to the persistent degradation of dryland ecosystems by climatic variations and human activities. It occurs on all continents (except Antarctica) and affects the livelihoods of millions of people, including a large proportion of the poor in drylands. Historically, dryland livelihoods have been based on a mixture of hunting, gathering, farming, and herding. This mixture varied with time, place, and culture, since the harsh conditions forced people to be flexible in their use of the land. Population pressure, has led to the extension of cultivated lands in dryland areas. This has caused desertification and conflicts between herders and farmers who claimed access to the same land.

Frequent and intensive fires can contribute to desertification when they affect natural vegetation. Limited controlled fires can play an important role in the management of dryland herding and farming systems, promoting nutrient cycling and forage quality.

546 1.jpg Ganado.jpg


How can we prevent or reverse desertification?


Effective prevention of desertification requires both local management and macro policy approaches that promote sustainability of ecosystem services.


Why are they taking action?


Because desertification is beginning to affect some areas more than others and most people in the world who are below the poverty line live in drylands.

What steps can help prevent desertification?


-It requires a change in government attitudes.

-Improved incentives by the population.

-The integrated management of land and water are key methods.

-The protection of vegetation.

-Opting for alternative methods and not using traditional ones.

-Creating urban centers in the drylands and areas beyond.

What actions can reverse land degradation?


-It takes a positive change in the interaction between people and ecosystems.

-They have a mixture of positive and negative impacts on ecosystems, human welfare and poverty reduction.

-In the cases where these conditions are not present, the rehabilitation efforts fail.

Arbol.jpg

Social, economic and political consequences of desertification



The desertification provokes in the affected countries a great number of problems and social conflicts: When the fertility of the land is diminished and the water turns into a scanty good, the supply of the population is in danger with food and drinkable water.

The affected people enter a spiral of destruction of the nature and the impoverishment that ultimately destroys the base of the subsistence.

Many people leave his homes in the field and migrate to the cities, where in general they meet obliged to live in poor bariums.

The desertificcion sharpens the social problems of the affected countries: it increases the rural exodus, the poverty, the badly nutrition and the risk of disease. Desertification refers to the persistent degradation of dryland ecosystems by climatic variations and human activities. It occurs on all continents (except Antarctica) and affects the livelihoods of millions of people, including a large proportion of the poor in drylands. The deserrtificación does not allow that there should take place an economic and social sustainable development in the affected countries. His fatal consequences concern especially Africa and also they give themselves in frauds regions of Latin America. For example: The North-East of Brazil, Central Asia and the basin of the south of the Mediterranean Desertificacion.jpg


SOLUCIONS

The gravity of the problem and to visualize possible solutions across new productive approaches that go from the intensification of the current productin, upto the restructuring of the agriculture companies. The new productive scenes include an extebsive rnage of possibilities that go from the utilization of the wealth landscape painter, the fauna, the agriculture of the areeas with water availabilities and conditions agricultures specify for certain cultures, between others.

Has given light to projects of green belts, which lines of trees reach to stop the advance of yhe desert. For example, there have been offers to plant this type of green belts on the whole contour of the desert of the Sahara.

In general, it has managed to wait for too much of the technical solutions to the problems of desertification in the last years new approaches have been designed to fight against the degradation of the drylands.

Nowadays it is emphisized the participation of the local communities, the reimplatation of traditional strategies times of environmetal stress, as the drought.

CONCLUSION


Desertification refers to the persistent degradation of dryland ecosystems by climatic variations and human activities. It occurs on all continents (except Antarctica) and affects the livelihoods of millions of people, including a large proportion of the poor in drylands.

Desertification poses one of the greatest environmental challenges today and constitutes a major barrier to meeting basic human needs in drylands.

Effectively dealing with desertification will help reduce global poverty, and is essential for meeting the Millennium Development Goals.

The greatest vulnerability is ascribed to sub-Saharan and Central Asian drylands.

In three key regions of Africa:The Sahel, The Horn of Africa and Southeast Africa.

Some 10 to 20% of drylands are already degraded

Based on these rough estimates, about 1–6% of the dryland people live in desertified areas, while a much larger number is under threat from further desertification.

These zones have severe droughts occur on average once every 30 years.


IMAGES

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