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More than 95% of world’s population breathe dangerous air, major study finds

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More than 95% of the world’s population breathe unsafe air and the burden is falling hardest on the poorest communities, with the gap between the most polluted and least polluted countries rising rapidly, a comprehensive study of global air pollution has found.

Cities are home to an increasing majority of the world’s people, exposing billions to unsafe air, particularly in developing countries, but in rural areas the risk of indoor air pollution is often caused by burning solid fuels. One in three people worldwide faces the double whammy of unsafe air both indoors and out.

The report by the Health Effects Institute used new findings such as satellite data and better monitoring to estimate the numbers of people exposed to air polluted above the levels deemed safe by the World Health Organisation. This exposure has made air pollution the fourth highest cause of death globally, after high blood pressure, diet and smoking, and the greatest environmental health risk.

Experts estimate that exposure to air pollution contributed to more than 6m deaths worldwide last year, playing a role in increasing the risk of stroke, heart attack, lung cancer and chronic lung disease. China and India accounted for more than half of the death toll.

Burning solid fuel such as coal or biomass in their homes for cooking or heating exposed 2.6 billion people to indoor air pollution in 2016, the report found. Indoor air pollution can also affect air quality in the surrounding area, with this effect contributing to one in four pollution deaths in India and nearly one in five in China.

Bob O’Keefe, vice-president of the institute, said the gap between the most polluted air on the planet and the least polluted was striking. While developed countries have made moves to clean up, many developing countries have fallen further behind while seeking economic growth.

He said there was now an 11-fold gap between the most polluted and least polluted areas, compared with a six-fold gap in 1990. “Air pollution control systems still lag behind economic development [in poorer nations],” he said.

But he added: “There are reasons for optimism, though there is a long way to go. China seems to be now moving pretty aggressively, for instance in cutting coal and on stronger controls. India has really begun to step up on indoor air pollution, for instance through the provision of LPG [liquefied petroleum gas] as a cooking fuel, and through electrification.”

The number of people exposed to indoor air pollution from burning solid fuels has fallen from an estimated 3.6 billion around the world in 1990 to about 2.4 billion today, despite a rising population.

Emissions from transport are a growing concern, however, as road traffic increases. Diesel fuel is a leading cause of air pollution in some rich countries, including the UK, but in poorer countries the often decrepit state of many vehicles means petrol-driven engines can be just as bad in their outputs, especially of the fine particulate matter blamed for millions of deaths a year.

O’Keefe said governments were under increasing pressure to deal with the problems through regulation and controls, and hailed internet access as having a significant impact.

Social media has been very important, as a growing number of people have access to it and to data and discussions [on air pollution]. People now have the ability to worry about not just the food they eat and a roof over the head, but they have the means to discuss [issues] in public,” he said.

Tuesday’s report reinforces an increasing volume of data in recent years that has shown how air pollution is increasing and causing deaths. More data has become available in the past decade from satellites and on-the-ground monitoring, while large-scale studies have revealed more of the health risks arising from breathing dirty air, which rarely kills people directly but is now known to contribute to other causes of death.

Source: theguardian.com

(Dipla Katerina)

Atmospheric Pollution – Part I: The problem of Atmospheric Pollution in Urban Areas.

Peter Essick, National Geographic

Pollution is any undesirable change in the physical, chemical or biological characteristics of air, soil or seas which adversely affects both flora and fauna of the planet. Air pollution is creating due to the accession of any material, molecular or particulate, to the atmosphere that surrounds us. This unnecessary influx of materials results in short or long-term pollution of life on Earth. Air pollutants are considered to be any material that may enter in it – through deliberate or unintentional processes – creating direct or indirect harmful influence on the organisms. Pollutants include specific chemicals and various forms of energy such as heat, sounds and radiation.

Under certain circumstances, air pollution is likely to reach levels that create unhealthy living conditions, so, it is necessary in this article to introduce the main sources of pollution and the harmful pollutants. In addition, it is important to explain how this situation is formed in the various urban centers of our country – especially in Attica – in order to realize the scope of the problem.

In modern times, the problem of atmospheric pollution is largely due to the anthropogenic factor. The main sources of air pollution due to human activities are: means of transport, domestic heating, electricity generation, unwanted combustion and generally industrial emissions. It is difficult to determine precisely the percentage of participation of each source in the general pollution problem, as our society is constantly evolving, so the contribution rates cannot be stable.

Image Source: Getty Images

Image Source: Getty Images

 

When we deal with the issue of air pollution, we usually refer to seven main groups of pollutants [Ref.1: Atmospheric Pollution, Ioannis Gentekakis, 2010]:

  1. carbon-containing compounds: such as carbon dioxide and carbon monoxide (CO2 & CO), hydrocarbons and their derivatives (H/Cs), methane (CH4) and volatile organic compounds (VOCs).
  2. nitrogen-containing compounds: such as nitrous oxide (Ν2Ο), nitrogen oxide and dioxide (ΝΟ & ΝΟ2), ammonia (ΝΗ3) and reactive nitrogen (ΝΟy).
  3. sulfur-containing compounds: such as sulfur dioxide (SO2), hydrogen sulfide (Η2S), ΟCS / carbonyl sulfide, dimethyl sulfide, CH3SCH3, DMS.
  4. halogen-containing compounds: such as the known halogen gases (CL2, F2, Br2) and hydrogen halides (HCl, HBr, HF) and the halogenated hydrocarbons which consist the basis of insecticides and herbicides, refrigerants or freons, fire extinguishers, sprays and cleansing / disinfecting agents.
  5. photochemical oxidants: which are the result of a series of complex atmospheric reactions that occur when active organic substances and oxides of nitrogen (NOx) accumulate in the atmosphere and are exposed to sunlight.
  6. particulate pollutants & aerosols: where particulate pollutants are all those non-gaseous substances in the atmosphere, and may include ions, molecule complexes, ice crystals, dust, tobacco particles, raindrops, pollen etc. which evolve into the atmosphere through various mechanisms.
  7. hazardous air pollutants, air toxics: a category of pollutants that are directly responsible for increasing mortality, or causing serious illnesses, or endanger human health, for example: alkyllated lead compounds, mercury and others.

 

Some of the substances, that are mentioned above, enter into the atmosphere directly after their emission from the source (primary pollutants), while others, considering the atmosphere as a large reactor, arise after some processes (secondary pollutants). The Environmental Sciences are extensively involved in the sources, appearance and impact of pollutants, so for more information you can refer to the literature at the end of the article, and this is generally a part of the topic “Atmospheric Pollution” that could not be confined to a single article.

Greece continues to face environmental problems and challenges. The main problems are in the control of emissions to the atmosphere from road transport, industrial enterprises and the extraction of large lignite (for electricity). In the large urban centers of our country (Athens, Thessaloniki, Patras, Heraklion, etc.), there have been identified mainly two types of atmospheric pollution that have been recognized for many years: high concentrations of PM and photochemical cloud, that is associated with nitrogen oxides (NOx), sulfur dioxide (SO2), smoke, hydrocarbons (HC) and carbon monoxide (CO) (which are primary pollutants) and the presence of various secondary pollutants, as a result of a series of chemical reactions caused by sunlight [2].

In particular, in the past decades, Athens experienced the yellow-brown photochemical smog that was a mixture of tobacco particles, carbon monoxide (CO), sulfur dioxide (SO2), nitrogen oxides (NOx) and ozone (O3) mainly internal combustion engines, central heating and exhaust gases from industries and crafts. However, over the years and in addition with the imposition of changes such as fuel improvement and vehicle replacement, the upgraded environmental legislation in order to restrict pollutants from crafts and industries, the relocation to industrial areas, and the import of natural gas as an energy fuel, have led to the gradual improvement of air quality in major cities.

We could admit that the condition of the atmosphere of major cities had a positive development until the appearance of the financial crisis in our country. The 2010-2017 crisis, that connected to the forthcoming increase in heating oil tax, is directly linked to the increase in photochemical pollutants (O3) and particulate matter (PM), despite the fact that in recent years it has declined air pollution with regard to the SO2, NOx, CO and exceedance of the alert thresholds of the concentrations of the different pollutants are less frequent than in the past. This means that the problem of air pollution is multidimensional, continuous, and we must approach it every time from a different perspective so that it can understood and eventually, resolved.

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Bolonaki Evropi,

Physicist – Physical Oceanographer

 

References

[1] «Ατμοσφαιρική Ρύπανση: επιπτώσεις, έλεγχος & εναλλακτικές τεχνολογίες- 2η έκδοση», Ιωάννης Γεντεκάκης, Publications: Κλειδάριθμος, 2010.

[2] «Atmospheric Pollution in Urban Areas of Greece and Economic Crisis.  Trends in air quality and atmospheric pollution data, research and adverse health effects», Valavanidis Athanasios, Thomais Vlachogianni, Spyridon Loridas, Constantinos Fiotakis, Department of Chemistry, University of Athens, University Campus Zografou, 15784 Athens, Greece, 20/11/2015, link: http://www.chem.uoa.gr/?p=6294

[3] «Οικολογία: Εισαγωγή στη Μελέτη του Περιβάλλοντος», Dr. Ν.Σ. Χριστοδουλάκης, Publications: Πατάκη.

 

China is about to get its first vertical forest

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They could be the breath of fresh air that pollution-choked cities desperately need. Vertical forests – high-rise buildings covered with trees and plants – absorb carbon dioxide, filter dust from pollution and produce oxygen. They’re also an ingenious way of planting more trees and creating habitats for wildlife in cities that are squeezed for space.

OK_SIbq5yr7L-k5Bqp_9tgZowPLlP7snhbVdFu8dPcYChina, a nation experiencing rocketing urban growth and an air pollution crisis, is set to get its first vertical forest. The project in the eastern city of Nanjing is the brainchild of the Italian architect Stefano Boeri and his team, who built Milan’s Bosco Verticale (vertical forest), consisting of two residential high-rises at 110 and 76 meters with around 900 trees and over 20,000 smaller plants and shrubs.

The Nanjing vertical forest will be higher than its Milanese predecessor, with two neighbouring towers at 200 and 108 meters tall. Scheduled for completion in 2018, the complex will house a 247-room luxury hotel, offices, shops, restaurants, a food market, conference and exhibition spaces, a museum, a rooftop club and even a green architecture school.

The skyscrapers will hold 1100 trees from 23 local species and 2500 cascading plants and shrubs, which the architects say will provide 25 tons of CO2 absorption each year and produce about 60 kg of oxygen a day.

From vertical forests to forest cities?

To put things in perspective, saving 25 tons of Co2 would be equivalent to taking five cars off the road for a year. Chinese cities have some of the most polluted air in the world. In December, air quality got so bad that 24 cities across north-east China were put on “red alert”. Schools were temporarily closed, flights were cancelled, vehicles ordered off the roads and residents urged to stay indoors until the smog eased.

Boeri told The Guardian that while his vertical forest will only make a tiny difference in Nanjing, he hopes it will act as a catalyst for more green architecture projects.

Two towers in a huge urban environment [such as Nanjing] is so, so small a contribution – but it is an example. We hope that this model of green architecture can be repeated and copied and replicated,” he said.

His firm, which has offices in Shanghai, has even bigger plans afoot – forest cities. It has come up with a concept for the northern industrial hub of Shijiazhuang, one of China’s most polluted cities, which envisions a compact and green mini-city for 100,000 people with buildings of different sizes covered in trees and plants.

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Today around 54% of the world’s population lives in urban areas – a proportion that is expected to increase to 66% by 2050, with most of the growth concentrated in Africa and Asia.

As more people move to cities, urban sprawl encroaches further into surrounding green space. Boeri conceived his vertical forests as a way of “giving back to nature the space we are taking from it”.

And the idea appears to be catching on. New examples of vertical greenery are springing up around the world, from Singapore’s “Supertrees” to Sydney’s One Central Park.

Source: weforum.org

Invest in forests and indigenous people to fight climate change – experts

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Efforts to protect carbon-absorbing forests, which could have a massive impact on reducing global warming, only attract a tiny fraction of the billions of dollars spent on cutting emissions, experts said, as they called for greater investment.

Almost 40 times more money has been spent on promoting agriculture and land development – which have led to large-scale deforestation – than on forest protection, they said in a study.

Forests hold so much potential in the effort to limit climate change, and yet there’s a seemingly endless supply of money to help tear them down,” said Charlotte Streck, director of environmental group Climate Focus.

Under the Paris deal, countries pledged to keep the rise in average global temperatures below 2 degrees Celsius above pre-industrial levels and to strive for a lower 1.5 degree limit, to stave off the worst effects of climate change.

Experts say forests could absorb enough carbon to meet about a third of the efforts needed to stick to those goals. But just 2 per cent of the $167 billion spent on reducing planet-warming carbon emissions since 2010 was invested in forests, according to the study by Climate Focus and other environmental groups.

Research has shown at least a quarter of the world’s carbon stored above the ground in tropical forests is found in territories managed by indigenous people and local communities. But even though deforestation rates are lower in areas where indigenous people manage forests, much of their knowledge is not taken into account when international decisions about climate change are made, experts say.

“Us indigenous peoples are sad and worried that billions of dollars are being invested in corporations that drive agro-business and cause deforestation,” Candido Mezua, an indigenous leader from Panama, told an event on forests at the Royal Society in London. “But very little is invested in what works: indigenous peoples and our forests, which are the best guarantee for a stable climate.”

At least 200 people were killed in 2016 while defending their homes, lands and forests from mining, dams and agricultural projects, according to advocacy group Global Witness.

Follow the link to learn more: http://www.eco-business.com/news/invest-in-forests-and-indigenous-people-to-fight-climate-change-experts/

Which Trees Offset Global Warming Best?

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Trees are important tools in the fight to stave off global warming, because they absorb and store the key greenhouse gas emitted by our cars and power plants, carbon dioxide (CO2), before it has a chance to reach the upper atmosphere where it can help trap heat around the Earth’s surface.

All Plants Absorb Carbon Dioxide, but Trees are Best

While all living plant matter absorbs CO2 as part of photosynthesis, trees process significantly more than smaller plants due to their large size and extensive root structures. In essence, trees, as kings of the plant world, have much more “woody biomass” to store CO2 than smaller plants, and as a result, are considered nature’s most efficient “carbon sinks”. It is this characteristic which makes planting trees a form of climate change mitigation.

According to the U.S. Department of Energy (DOE), tree species that grow quickly and live long are ideal carbon sinks. Unfortunately, these two attributes are usually mutually exclusive. Given the choice, foresters interested in maximizing the absorption and storage of CO2 (known as “carbon sequestration”) usually favor younger trees that grow more quickly than their older cohorts. However, slower growing trees can store much more carbon over their significantly longer lives.

Plant the Right Tree in the Right Location

Scientists are busy studying the carbon sequestration potential of different types of trees in various parts of the U.S., including Eucalyptus in Hawaii, loblolly pine in the Southeast, bottomland hardwoods in Mississippi, and poplars (aspens) in the Great Lakes region.

There are literally dozens of tree species that could be planted depending upon location, climate, and soils, says Stan Wullschleger, a researcher at Tennessee’s Oak Ridge National Laboratory who specializes in the physiological response of plants to global climate change.

Plant Any Tree Appropriate for Region and Climate to Offset Global Warming

Ultimately, trees of any shape, size or genetic origin help absorb CO2. Most scientists agree that the least expensive and perhaps easiest way for individuals to help offset the CO2 that they generate in their everyday lives is to plant a tree…any tree, as long as it is appropriate for the given region and climate.

Follow the link to learn more: https://www.thoughtco.com/which-trees-offset-global-warming-1204209

First-ever ‘negative emissions’ power plant goes online

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Unfortunately, it’s no longer enough to cut CO2 emissions to avoid further global temperature increases. We need to remove some of the CO2 that’s already there. Thankfully, that reversal is one step closer to becoming reality. Climeworks and Reykjavik Energy have started running the first power plant confirmed to produce “negative emissions” — that is, it’s removing more CO2 than it puts out. The geothermal station in Hellsheidi, Iceland is using a Climeworks module and the plant’s own heat to snatch CO2 directly from the air via filters, bind it to water and send it underground where it will mineralize into harmless carbonates.

Just like naturally forming carbon deposits, the captured CO2 should remain locked away for many millions of years, if not billions. And because the basalt layers you need to house the CO2 are relatively common, it might be relatively easy to set up negative emissions plants in many places around the world.

As always, there are catches. The Hellsheidi plant capture system is still an experiment, and the 50 metric tonnes of CO2 it’ll capture per year (49.2 imperial tons) isn’t about to offset many decades of fossil fuel abuse. There’s also the matter of reducing the cost of capturing CO2. Even if Climeworks improves the efficiency of its system to spend $100 for every metric ton of CO2 it removes, you’re still looking at hundreds of billions of dollars (if not over a trillion) spent every year to achieve the scale needed to make a difference. That will require countries to not only respect climate science, but care about it enough to spend significant chunks of their budgets on capture technology.

It could be a long while before you see systems like this implemented on a global scale as a result.

Follow the link to learn more: https://www.engadget.com/2017/10/14/negative-emissions-power-plant-online/

Floating Tar, Dead Fish: Oil Spill Threatens Greek Beaches

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The Greek authorities scrambled on Thursday to clean up fuel leaked by an oil tanker that sank near Athens, putting popular beaches off limits to swimmers and raising fears of environmental damage.

The Agia Zoni II, a 45-year-old oil tanker, sank near the island of Salamis, about seven miles from the country’s main port, Piraeus. It was carrying more than 2,500 metric tons of fuel oil and marine gas oil.

Though the leak was initially thought to be contained to the area of the shipwreck, it soon expanded to the coastline area known as the Athens Riviera.

Evaggelia Simou, a resident of Salamina, on the island, denounced the authorities for not tackling the oil spill more quickly and fully.

“We drove by the Selinia beach on Sunday night, and were alarmed because of the suffocating smell of oil,” Ms. Simou said.

When she and her husband went to the beach, they were shocked to see that a thick coat of oil had blackened the water. “Huge pieces of floating tar were burdening the waves, dead fish floated on the surface,” Ms. Simou said. They were surprised to see no cleanup workers, she said.

George Papanikolaou, the mayor of Glyfada, said he got a phone call from the Piraeus harbor master warning of the spill only a few hours before the black ooze washed up.

Since then, three private antipollution vessels have cleaned up more than 180 metric tons of fuel from Glyfada’s four beaches. Just this summer, one of the beaches had been recognized by the Foundation for Environmental Education as a Blue Flag beach, a certification of water quality.

It’s tragic that it happened now, after all four beaches have gotten so beautiful,” Tima Vlasto, 51, an American who has lived in Glyfada for six years, said in a phone interview. “Seeing this makes you want to leave. If I can’t swim here, what’s the point of living in Glyfada?”

Mr. Papanikolaou said that emotions were running high in his community. “We’re angry”, he said. “It’s just such a shame that all this hard work can be destroyed in a split second.”

Some ecologists have called the oil spill an environmental disaster, with immediate and potential long-term effects.

The full extent of the pollution and its effects are not yet clear; areas like uninhabited rocky islets are also thought to be affected.

The Hellenic Register of Shipping, an independent organization that oversees shipping safety, said that the tanker had not been certified as seaworthy, although its owner, Fos Petroleum, said that it had all of the proper credentials. The Greek Ministry of Shipping and Island Policy did not respond to several requests for information.

Read here the full article: https://www.nytimes.com/2017/09/14/world/europe/greece-oil-spill.html?mcubz=1

“Importance and Value of Trees”

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Since the beginning, trees have furnished us with two of life’s essentials, food and oxygen. As we evolved, they provided additional necessities such as shelter, medicine, and tools. Today, their value continues to increase and more benefits of trees are being discovered as their role expands to satisfy the needs created by our modern lifestyles.

Here, some important benefits of the trees that you probably didn’t know:

  1. An acre of nature trees absorbs the amount of CO2 produced when you drive your car 42.000 Km.
  1. An acre of nature trees provides enough oxygen for 18 people.
  1. Trees reduce UV-B exposure by about 40 percent.
  1. The evaporation from a single tree can produce the cooling effect of 10 room size air-conditioners operating 20 hours a day.
  1. A well placed tree can reduce noise by as much as 40 percent.
  1. One large tree can supply a days’ supply of oxygen for 4 people.
  1. A healthy tree can store 6 kg of carbon each year.
  1. An acre of trees can store 2.6 tons of carbon dioxide each year.
  1. For every 16.000 km you drive, it takes 7 trees to remove the amount of carbon dioxide produced.
  1. A hundred million new trees would absorb 18 million tons of CO2 and cut air-conditioning cost by 84 billion annually.
  1. A belt of trees 40 meters wide and 12 meters high can reduce highway noise by 40 percent.
  1. A tree can absorb as much as 24 kg of CO2 per year and can sequester on ton of CO2 by the time it reaches 40 years old.
  1. A mature tree can have an appraised value between 1.000$ and 10.000$ council of Tree and Landscape Appraisers.
  1. About 20 percent of the worlds’ emissions are a result of deforestation.
  1. CO2 worlds’ emission is 35.000.000 metric tons per year.
  1. CO2 sequestration is 25 kg per tree per year.
  1. One half the dry weight of wood is carbon.
  1. One person emit 20 ton of CO2 per year.

So, what you have to do is “take action”, and just plant a tree. It is so simple, but so important!! Protect the environment!! Do not destroy it!!

Dipla Aikaterini (Arid Zone Afforestation)

 

 

Soil erosion and degradation: a global problem – Effects (Part 2)

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The consequences of soil erosion are primarily centered on reduced agricultural productivity, as well as soil quality. But also, water ways may be blocked, and it may affect water quality. This means, most of the environmental problems the world face today, arises from soil erosion.

Particularly, the effects of soil erosion go beyond the loss of fertile land. In other words, it has led to increased pollution and sedimentation in streams and rivers, clogging these waterways and causing declines in fish and other species. And degraded lands are also often less able to hold onto water, which can worsen flooding.

So, the effects of soil degradation include:

  1. Loss of arable land: Lands used for crop production have been substantially affected by soil erosion. Soil erosion eats away the top soil which is the fertile layer of the land and also the component that supports the soil’s essential microorganisms and organic matter. In this view, soil erosion has severely threatened the productivity of fertile cropping areas as they are continually degraded. Because of soil erosion, most of the soil characteristics that support agriculture have been lost, causing ecological collapse and mass starvation.
  1. Water Pollution and Clogging of Waterways: Soils eroded from agricultural lands, carry pesticides, heavy metals, and fertilizers which are washed into streams and major water ways. This leads to water pollution and damage to marine and freshwater habitats. Accumulated sediments can also cause clogging of water ways and raises the water level leading to flooding.
  1. Increased flooding: Land is commonly altered from its natural landscape when it rids its physical composition from soil degradation. In other words, soil degradation takes away the soil’s natural capability of holding water thus contributing to more and more cases of flooding.
  1. Drought and Aridity: Drought and aridity are problems highly influenced and amplified by soil degradation. As much as it’s a concern associated with natural environments in arid and semi-arid areas, the UN recognizes the fact that drought and aridity are anthropogenic induced factors especially as an outcome of soil degradation. Hence, the contributing factors to soil quality decline such as overgrazing, poor tillage methods, and deforestation are also the leading causes of desertification characterized by droughts and arid conditions.
  1. Destruction of Infrastructure: Soil erosion can affect infrastructural projects such as dams, drainages, and embankments, reducing their operational lifetime and efficiency. Also, the silt up can support plant life that can, in turn, cause cracks and weaken the structures. Soil erosion from surface water runoff often causes serious damage to roads and tracks, especially if stabilizing techniques are not used.
  1. Desertification: Soil erosion is also responsible for desertification. It gradually transforms a habitable land into deserts. The transformations are worsened by the destructive use of the land and deforestation that leaves the soil naked and open to erosion. This usually leads to loss of biodiversity, alteration of ecosystems, land degradation, and huge economic losses.

Finally, we all understand that the erosion of the soil is a very serious issue, especially in our days. That is why we need to take action and prevent the unpleasant effects.

Dipla Aikaterini (Arid Zone Afforestation)

Sources:

 

 

Soil erosion and degradation: a global problem – Causes (Part 1)

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Soil degradation, defined as lowering and losing of soil functions, is becoming more and more serious worldwide in recent decades, and poses a threat to agricultural production and terrestrial ecosystem.

Particularly, soil degradation simply means the decline in soil quality, which comes about due to aspects such as improper land use, agriculture and pasture, urban or industrial purposes. It involves the decline of the soil’s physical, biological and chemical state. In other words, it is a process that leads to decline in the fertility or future productive capacity of soil, as a result of human activity.

It is well known that all soils undergo soil erosion, but some are more vulnerable than others, due to human activities and other natural causal factors. The severity of soil erosion is also dependent on the soil type and the presence of vegetation cover.

Here are few of the major causes of soil degradation:

  1. Physical factors: There are several physical factors contributing to soil degradation, distinguished by the manners in which they change the natural composition and structure of the soil.  Rainfall, surface runoff, floods, wind erosion, tillage, and mass movements result in the loss of fertile top spoil thereby declining soil quality. All these physical factors produces different types of soil erosion (mainly water and wind erosion) and soil detachment actions, and their resultant physical forces eventually changes the composition and structure of the soil by wearing away the soil’s top layer as well as organic matter.
  1. Chemical factors: The reduction of soil nutrients because of alkalinity or acidity or water logging, are all categorized under the chemical components of soil degradation. In the broadest sense, it comprises alterations in the soil’s chemical property that determine nutrient availability.
  1. Biological factors: Biological factors refer to the human and plant activities that tend to reduce the quality of soil.  Some bacteria and fungi overgrowth in an area can highly impact the microbial activity of the soil through bio-chemical reactions, which reduces crop yield and the suitability of soil productivity capacity. Also, human activities such as poor farming practices may also deplete soil nutrients thus diminishing soil fertility.
  1. Deforestation: Deforestation causes soil degradation on the account of exposing soil minerals by removing trees and crop cover, which support the availability of humus and litter layers on the surface of the soil. When trees are removed by logging, infiltration rates become elevated and the soil remains bare and exposed to erosion and the buildup of toxicities.
  1. Improper cultivation practices: There are certain agricultural practices that are environmentally unsustainable and at the same time, they are the single biggest contributor to the worldwide increase in soil quality decline. For example, due to shortage of land, increase of population and economic pressure, the farmers have adopted intensive cropping patterns of commercial crops in place of more balanced cereal-legume rotations.
  1. Misuse and Extensive cultivation: The excessive use and the misuse of pesticides and chemical fertilizers kill organisms that assist in binding the soil together. In other words, it increases the rate of soil degradation by destroying the soil’s biological activity and builds up of toxicities through incorrect fertilizer use. We all know that due to tremendous population increase, the use of land is increasing day by day.
  1. Overgrazing: The rates of soil erosion and the loss of soil nutrients as well as the top soil, are highly contributed by overgrazing. Overgrazing destroys surface crop cover and breaks down soil particles, increasing the rates of soil erosion. As a result, soil quality and agricultural productivity is greatly affected.
  1. Industrial and Mining activities: Soil is chiefly polluted by industrial and mining activities. For example, mining destroys crop cover and releases a myriad of toxic chemicals such as mercury into the soil thereby poisoning it and rendering it unproductive for any other purpose. Industrial activities, on the other hand, release toxic effluents and material wastes into the atmosphere, land, rivers, and ground water that eventually pollute the soil and as such, it impacts on soil quality. Altogether, industrial and mining activities degrade the soil’s physical, chemical and biological properties.
  1. Roads and Urbanization: Urbanization severely affects the erosion process. Land denudation by removing vegetation cover, changing drainage patterns, soil compaction during construction and then covering the land by impermeable layers of concrete or asphalt, all of them contribute to increased surface runoff and increased wind speeds.

Finally, taking into consideration all the above, we understand that soil erosion is a continuous process and may occur either at a relatively unnoticed rate or an alarming rate contributing to copious loss of the topsoil. So, we have to be careful and avoid all the above problems.

Dipla Aikaterini (Arid Zone Afforestation)

Sources: