Marine and Coastal Systems

An adequate and clean supply of fresh water is vital to our survival and to Earth’s ecosystems, but recall that fresh water makes up only 2,5% of our planet’s water. Fully 97,5% is salt water, comprising the oceans that cover 71% of our planet’s surface. The oceans influence global climate, teem with biodiversity, facilitate transportation and commerce, and provide us many resources.

The world’s five major oceans – Pacific, Atlantic, Indian, Artic, and Antartic – are all connected, comprising a single vast body of water. Ocean water is salty primarily becase rivers and winds carry sediments and sals from the continents into the ocean. Evaporation then removes pure water, leaving a higher concentration of salts. If we were able to evporate all the water from the ocean, the world’s ocean basins would be covered with a layer of dried salt 63m (207 ft) thick.

Surface waters of the oceans are warmer than subsurface waters because the sun heat them and because warmer water is less dense. Deepbelow the surface, water is dense and sluggish, unaffected by winds and storms, sunlight, and daily temperature fluctuations. Ocen water moves in currents, vast riverlike flows that move in the upper 400m of water, horizontally and for great distances. Wind, solar heating and coling, gravity, density differences, and the Coriolis effect drive the global system of ocean currents. hese lon lasting patterns influence global climate, El Niño andLa Niña events, and navigation and human history.

Marine and coastal ecosystems are diverse. Their variation in topography, temperature, salinity, nutriens, and sunlight, marine and coastal environments feature  variety ofecosystems:

• Near-surface pelagic ecosystem – areas oft he open ocean where the photosynthetic productivity is concentrated near the suface in regions o nutrient-rich upwelling. Phytoplankton constitute the base of the marine food chain. Pedators at higher trophic levels include larger fish, sea turtles, shraks, and seabirds.

• Deep ocean – little-known, the deep ocean’s animals have adapted to deal with extreme water pressures and to live in th dark without food from photosynthesizers. Some of these bizarre-looking creatures scavenge carcasses or detritus that fall from above.

 

• Kelp forets - large brown algae, or kelp, grow from the floor of continental shelves, reaching toward the sunlit surface for up to 60m  (200 ft) in height.  Dense stands of kelp form underwater forests in many temperate waters. Kelp forests supply shelter an food for invertebrates and fish, which in turn provide food for predators such as seals, sharks, and seaotters. Kelp forests also absorb wave energy and protect shorelines from erosion. People derive alginates from kelp, which serve as thickeners in a wide range of consumer prducts, from cosmetics to foods to pains to paper to soaps.

• Coral reefs - is an underwater outcrop of calcium carbonate composed of the skeletons o tiny marine aimals known as corals. Corals attach to rock of existing reef nd capture passing food with stinging tentacles. They also derive nouishment from symbiotic algae, known as zooxanthellae, that inhabit their bodies and produce food through photosynthesis. Most corals are colonial, and the colorful surface of  coral reef consists of thousands of millions of densely packed individuals. As corals die, their skeletons remain part o the reef while new corals grow atop them, increasing the reef’s size. They absorb wave energy, protect shorelines, and host as much biodiversity as any other type of ecosysem. The likely rason is that coral reefs provide complex physical structure in shallow nearshore waters, which are regions of high primary productivity. Besides the staggering diversity of anemones, sponges, hydroids, tubeworms, and other sessile invertebrates, innumerable molluscs, crustaceans, flatworms, seastars, and urchins patrol the reefs, and thousans of fish species fnd food and shelter in reefnooks and crannies. Larger predators, such as grouper and mora eels, feed on the smaller fish.

• Intertidal zones – where he ocean meets the land, intertidal, or littoral, eosystems extend between the farthest reaches of the high and low tides, which are the periodic rising and falling of the ocean’s heigh at a given location, caused  by the graviational pullof the moon and sun. Intertidal organisms spend part of each day submerged in water, part of the day exposed to the air and sun, and part of the day being lashed by waves. Sessile nimals such as anemones, mussels, and barnacles live attached t rocks, filter-feeding on plankton in the water that washes over them.

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• Salt marshes – along many of the world’s coaslines at temperate latitudes, salt marshes occur where the tides wash over gently sloping sandy or silty substrates. Rising and falling tides fow into and out of channels, and at highest tide, water spills over onto elevated marsh flats. Marsh flats grow thick with rushes, shrubs, and grasses. Salt marshes boast very high primary poductivity and provide critical habitat for shorebirds, waterfowl, and the adults and young of many commercially important fish and shellfih species.

• Mangroe forests – in tropical and subtropical latitudes, mangroveforests occur along sandy and silty coasts. Mangroves are trees with odd rots, some of which curve upward like snorkels to attain oxygen lacking in the mud, and some of which curve downward, serving as silts to support the tree in changing water levels. Fish, shelfish, crabs, snakes, and other organisms thrive amont the root network, and bird feed and nest in the foliage of these coastal forests. Mangroves protect coastlines; studies fter the 2004 South Asian tsunami indicated that coasts wth intact mangrove forests suffered less damage than deforested coasts.

• Estuaries - many salt marshes and mangrove forests occur in or near estuaries, water bodies where river flow in the ocean, mixing fresh water with salt water. Biologically productive ecosystems, estuaries experience significant fluctuations in salinity as tital currents and freshwater runoff vary daily and seasonally. For shorebirds and for many commercially important shellfish species, estuaries provide critical habitat.

Water Pollution

The quantity and distribution of fresh water pose one set of environmental and social challenge. Safeguarding the quality of water involves another collection of environmental and human health dilemmas. Developed nations have made admirable advances in clearing up water pollution over the past few decades. Still, the World Commission on Water recently concluded that over half the world’s major rivers are “seriously depleted and polluted, degrading and poisoning the surrounding ecosystems, threatening the health and livelihood of people who depend on them”.

The term pollution describes the release of matter or energy into the environment that causes undesirable impact on the health and well-being of people or other organisms. Pollution can affect water, air or soil, and can be:

• Physical  – scientists use temperature, color and turbidity, which measures the density of suspended particles in a water sample. Fast-moving rivers that cut through arid or eroded landscapes, such as the Colorado River, carry a great deal of sediment and are turbid and muddy-looking as a result. If scientists can measure only one parameter, they will often choose turbidity, because it tends to correlate with many others and is thus a good indicator of overall water quality.
• Chemical –nutrients concentrations, pH, taste and odor, and hardness. Hard water contains high concentrations of calcium and magnesium ions, prevents soap from lathering, and leaves chalky deposits behind when heated or boiled. An important characteristic is dissolved oxygen content, which is an indicator of aquatic ecosystem health because surface waters that are low in dissolved oxygen support less aquatic life.
• Biological – is the presence of fecal coliform bacteria, which indicates contamination by human waste and suggest the presence of other disease-causing organisms. Scientists can identified biological pollution using algae and aquatic invertebrates.

 

Water pollution comes in many forms and can cause diverse impacts on aquatic ecosystems and human health:

• Nutrient pollution – is the pollution from fertilizers and other sources that can lead to eutrophication and hypoxia in coastal marine areas.

• Pathogens and waterborne diseases – disease-causing organisms (pathogenic viruses, protists, and bacteria) can enter drinking water supplies when these are contaminated with human waste or with animal waste from feedlots. Biological pollution by pathogens causes more human health problems than any other type of water pollution. Treating sewage constitutes one approach for reducing health risks. Another is using chemical or other means to disinfect drinking water. Personal hygiene is vital, as is government enforcement of regulations to ensure the cleanliness of food production, processing, and distribution.

• Toxic chemicals – our waterways have become polluted with toxic organic substances of our own making, including pesticides, petroleum products, and other synthetic chemicals. Many of these can poison animal and plants, alter aquatic ecosystems, and cause an array of human health problems, including cancer. Toxic metals such as arsenic, lead, and mercury, as well as acids from acid precipitation and from acid drainage from mining sites, also cause negative impacts on human health and the environment. Legislation and enforcing stricter regulations of industry can help reduce releases of toxic chemicals. We can also modify our industrial process and our purchasing decisions to rely less on these substances.

• Sediment – floods build fertile farmland, but sediment that rivers transport can also impair aquatic ecosystems. Mining, clear cutting, overgrazing, land clearing for housing development, and tilling of farm fields all expose soil to wind and water erosion. Some water bodies, such as the Colorado River and China’s Yellow River, are naturally sediment-rich, but many others are not. When a clear-water river receives a heavy influx of eroded sediment, aquatic habitat can change dramatically, and fish adapted to clear-water environments may not be able to adjust. We can reduce sediment pollution by better managing farms and forests and by avoiding large-scale disturbance of vegetation.

• Thermal pollution – water’s ability to hold dissolved oxygen decreases as temperature rises, so some aquatic organisms may die when human activities heat water. When we withdraw water from a river and use it to cool an industrial facility, we transfer heat energy from the facility back into the river where the water is returned. The temperature might also be raised by removing streamside vegetation that shades water. Too little heat can also cause problems.  On the Colorado and other dammed rivers, water at the bottoms of reservoirs is colder than water at the surface. When dam operators release water from the depths of a reservoir, downstream water temperatures drop suddenly. In the Colorado’s system, these low water temperatures have favored cold-loving invasive trout over and endangered native species of suckerfish.

Water

Ok, after talking a lot about soil, rocks and agriculture, let’s talk a little bit about water.

I guess it’s not unknown that even though water is abundant, the water that we can drink is quire rare. If 97,5% of Earth’s water resides in the oceans and is too salty to drink or use to water crops, than it lasts only 2,5% of the type considered fresh, which is water with few dissolved salts. Since most fresh water is tied up in calaciers, icecaps, and underground aquifers, just over 1 part in 10,000 of Earth’s water is easily accessible for human use.

Water constantly moves via the hydrologic cycle and, as it moves, it redistributes heat, erodes mountain ranges, builds river deltas, maintains organisms and ecosystems, shapes civilizations, and gives rise to political conflicts.

The freshwater ecosystems are rich in life, and they are:

• Rivers and streams – water from rain, snowmelt,or springs runs downhill and converges where the land dips lowest, forming streams, creeks, or brooks. These water-courses merge into rivers;

• Lakes and ponds – bodies of open standing water. Their physical conditions and the types of life within them vary with depth and the distance from shore.

• Marshes, swamps, and bogs – systems that combine elements of fresh water and dry land. They’re also called wetlands, and are very rich and productive.

Groundwater is very important to the hydrologic cycle because the precipitation that reach Earth’s land surface and does not evaporate, flow into waterways, or get taken up by organisms infiltrates the surface. Most percolates downward through the soil to become groundwater.

Groundwater is contained within aquifers, porous, spongelike formations of rock, sand, or gravel that hold water. The world’s largest known aquifer is the Ogallala Aquifer, which underlines the Great Plains beneath eight US states from South Dakota to Texas. However, overpumping for irrigation has reduced this aquifer’s volume by nearly 10% so far -a volume equal to 18 years’worth of the entire flow of the Coloado River.

Unfortunatelly for us, different regions of the world possess vastly different amounts of groundwater, surface water, and precipitation. However, people are not distributed across the globe in accordance with water availability. Canada, for instance, has 20 times more water per citizan than does China; the Amazon River carries 15% of the world’s runoff, but its watershed holds less than half a percent of the world’s population. Many countries like Pakistan, Iran and Egypt face water shortages.

Because fresh water is distributed unevenly in time and space, it became necessary to erect  dams to store water, so that it may be distributed when needed. In India, monsoon storms can dump half of a region’s annual rain in just a few hours. Northwest China receivs three-fifths of its annual precipitation during 3 months, when crops do not need it.

We divert and deplete surface wter to suit our needs. Water from rivers, streams, lakes and ponds are diverted to homes, cities, and farm fields. The Colorado River’s water, for instance, is heavily diverted and utilized, in a way that after all the diversions comprised, just a trickle makes its way to the Gulf of California. There are some days when water does not reach the Gulf at all. This flow reduction has altered drastically the river and its once rich delta; plant communities were modified and populations of fish and aquatic invertebrates where wipped out, devastating fisheries.

We are depleting groundwater more than surface water because most aquifers recharge very slowly. Most groundwater use goes toward agriculure. We withdraw 70% more water for irrigation today than in 1960, and since then, the amount of land under irrigation has doubled. Expansion of irrigated agriculture has kept pace with population growth. Irrigation can more than double crop yields by allowing farmers to apply water when and where it is needed. Still, most irrigation remains inefficient, and overirrigatin leads to waterlogging and salinization.

Worldwide today, 15-35% of irrigation withdrawals are thought to be unsustainable, and like Ogallala, many aquifers are being drained as water is “mined” at rates faster than it is recharged. As aquifers are depleted, water tables drop. Groundwater becomes more difficult and expensive to extract, and eventually it may run out. To make the situation even worse, when groundwater is overpumped in coastal areas, salt water can intrude into aquifers, making water undrinkable; and as aquifers lose water, the land surface aboe may subside, that’s the reason why cities from Venice to Bangkok to Mexico City are slowly sinking, while streets buckle, buildings flood, and pipes break.

Still, there are some solutions to depletion of fresh water:

• To address the depletion, we can aim either to increase supply or to reduce demand, lowering demand is more difficult politically but will likely be necessary in the long term;
• To increase supply in a giver area, people have transported water through pipes and aqueducts from areas where it is more plentiful or accessible. In many instances, water-poor regions have forcibly appopriated water from commmunities too weak to keep it for themselves. Los Angeles, for instance, grew by using water it appropriated from the Owens Valley, Mono Lake, and other rural regions of California. Becaouse of that, these area’s environments are desertified, crating dustbowls and devastating local economies.
• Desalination  also may help. The process of “making” fresh water by removing salt from seawater or other water of marginal quality. However, desalination is expensve, requires large inputs of fossil fuel energy, and generates concentrated salty waste. Over 7,500 desalination facilities are operating worldwide. Most are in the Middle East, where water is scarce and oil is cheap.
• To decrease demand farmers can improve efficiency by lining irrigation canals to prevent leaks, leveling fields to minimize runoff, and adopting efficient irrigation methods.
• Choosing crops to match the land and climate in which they are being farmed can save huge amounts of water. Crops that require a great deal of water are cotton, rice and alfalfa are often planted in arid areas with government-subsidized irrigation. In this way, the true cost of water is not part of the cost of growing the crop.

Sustainable Architecture

Sustainable Architecture is a general term that describes environmentally-conscious design techniques in the field of architecture. It is framed by the larger discussion of sustainability and the pressing economic and political issues of our world. In the broad context, sustainable architecture seeks to minimize the negative environmental impact of buildings by enhancing efficiency and moderation in the use of materials, energy, and development space.

The Sustainable Architecture has three different dimensions:

Economic:

• Creation of new markets and opportunities for sales growth. Since this is a new issue in Architecture, news firms specialized in sustainable architectures will open, where new researches will happen. And since the firms and the universities are connected,  new teachers at schools of architecture will be needed;
• Cost reduction through efficiency improvements and reduced energy and raw material inputs. Research for new equipments that use less energy, or use of different kinds of energy like solar and wind. Thinking about materials, if the US use a material made in US instead of a material made in China, there will be an energy reduction on the transportation process;
• Creation of additional added value. It means that you can even charge more for the project because it has a sustainable issue. Or not tlaking about money, if a firm is looking for a project for its building (if one considered sustainable topics and the other is not, it can be an advantage for the first one due to nowadays it’s importance for companies to have a social and environment concerns).

Environmental:

• Reduced waste, effluent generation, emissions to environment;
• Reduced impact on human health ;
• Use of renewable raw materials;
• Elimination of toxic substances;

Social:

• Worker health and safety;
• Impacts on local communities, quality of life;
• Benefits to disadvantaged groups e.g. disabled;

Using these dimensions we can find different forms and examples of sustainable architecture as we see at the Norman Foster Architect’ works and Studio Rural’s work – Auburn, AL. (for example).

 

 

 

 

Foster’s idea of sustainable architecture is related to business innovation, new opportunity that creates an additional value for the building, using high-technologies to try to get the target zero carbon and waste free of materials.

On the other side, The Rural Studio seeks solutions to the needs of the community within the community’s own context, not from outside it. Abstract ideas based upon knowledge and study are transformed into workable solutions forged by real human contact, personal realization, and a gained appreciation for the culture. So, it is a partnership between students of architecture and community that works with social impact on local communities.

Feedlots and its Impacts

In this post I’m going to talk about feedlots and the positive and negative sides of it’s practice.

I’d like to make it clear that my goal here is not to make apology to vegetarianism, I don’t want to convince anyone to give up on eating meat, that’s not my place. That being said, let’s start!

Feedlots are also known as factory farms or concentrated animal feeding operations (CAFOs), and they’re essentially huge waterhouses or pens designed to deliver energy-rich food to animals living at extremely high densities. Nowadays, over half our pork and poultry come from feedlots, as does much of our beef.

The positive side of feedlots are:

• Allow for greater production of food. This is necessary for a country with a level of meat consumption like the US – without entering the merit if the country consumes more meat than they should, let’s try to only deal with the facts;
• They have one overcharging benefit for environmental quality: when cattle, sheep, goats, and other livestock are taken off the land and concentrated in feedlots, there is a reduction on the impacts they would otherwise exert on large portions of the landscape;

The negative side of feedlots are:

• It’s waste can emit strong odors and pollute surface water and groundwater, because livestock produce prodigious amounts of feces and urine;
• Poor waste containment practices might cause outbreaks of disease like Pfiesteria, a microbe that poisons fish;
• The crowded and dirty conditions under which animals are kept makes the heavy use of antibiotics necessary to control disease. These chemicals can be transferred up to food chain and we don’t know if they might cause us harm;
• The overuse of antibiotics can cause microbes to evolve resistance to them;
• There is the ethical issue among cruelty to animals, because the environment they live their whole lives are very stressful and dirty, and the way theiy’re killed is not the least pain possible;

• There is the controversy wether if it is healthy or not to eat meat. Environmentalists say it is not, but some doctors say it is;
• If we eat meat, we consume much more energy, water and soil resources, and therefore, we increase our carbon footprint. In fact, researches estimate that beef requires 16 times more fossil fuel energy and creates 24 times more greenhouse gas emissions than a mixed diet of vegetables and grains.
• Some animals require more resources than others. Producing eggs and chicken meat requires the least space and water, whereas producing beef requires the most. In fact, to produce 1kg (2,2 lb) of food protein for milk, eggs, chicken, pork and beef; beef needs 20kg of food, 245 m² of land, and 750 kg of water; pork needs 7,3 kg of food, 90 m² of land, and 175 kg of water; for eggs production, chicken needs 4.5 kg of food, 22 m² of land, and 15kg of water; chicken needs 2.8kg of food, 14 m² of land, and 50 kg of water; and to produce 1 kg of milk, a cow needs 1,1kg of food, 23,5 m² of land, and 250 kg of water. Therefore, when we eat meat, we don’t eat just the meat, but also the resources necessary to produce them.
• Meat is less energy efficient than a vegetarian diet, and pyramids of energy explain that. Each time energy moves from one trophic level to the next, as much as 90% is lost. In a few words, if we feed grain to a cow and than eat beef from the cow, we lose most of the grain’s energy to the cow’s metabolism. Energy is used up as the cow converts the grain to tissue as it grows, and as the cow uses its tissues and respires on daily basis. The lower in the food chain we take our food sources, the greater the proportion of the sun’s energy we use, and the more people Earth can support

Scientists developed lab grown meat, a new way to produce artificial meat. This way, people will still be able to eat meat and there will be no animal cruelty or use of natural resources. However, some questions still remains… who would eat it? Many people say their not comfortable with the idea of eating something that is not natural… in this way of thinking, is transgenics being considered natural food?

Read an article at the New York times about this.

Genetic modified organisms

The genetic modification of organisms started with the green revolution, when it was necessary to modernize agriculture to increase food production. The GMOs promise to increase nutrition and the efficiency of agriculture while lessening impacts on the planet’s environmental system. However, they also may pose risks that are not yet well understood, and this concern has given rise to protests around the globe from consumer advocates, small farmers, environmental activists, and opponents of big business.

The genetic modification of crops and livestock is one type of genetic engineering, a process whereby scientists manipulate an organism’s genetic material in the laboratory by adding, deleting, or changing segments of its DNA. GMOs are organisms that have been genetically engineered using recombinant DNA, genetic material patched together from the DNA of different organisms. In this process, scientists break up DNA from multiple organisms and then splice segments together, placing genes that produce certain proteins and code for certain desirable traits -like rapid growth, disease and pest resistance, or higher nutritional content – into the genomes of organisms lacking those traits. An organism that contains DNA from another species is called a transgenic organism, and the genes that have moved between them are called transgenes. To se an animation of the transgenic mouse, click here.

Genetic alteration of plants and animals by humans is not something very new. Mendel was actually the first one. However, there is a difference between Mendel’s GMOs, selective breedings, and the ones from genetic engineering, and it lays is on the technique:

• Selective breeding mixes genes from individuals of the same or similar species, while with recombinant DNA technology, scientists mix genes of organisms as different as viruses and crops, or spiders and goats.
• Selective breeding deals with whole organisms living in the field, and genetic engineering involves lab experiments; it deals with genetic material apart from the organism.
• While traditional breeding selects from among combinations of genes that come together on their own, genetic engineering creates the novel combinations directly.
• Traditional breeding changes organisms through the process of selection, while genetic engineering is more akin to the process of mutation.

The impacts of GM crops are many, however, there is no study or research yet to prove them, nevertheless, some of these consequences have been already seen in some places. Eitherway, the concerns are:

• That the new foods might be dangerous for people to eat, since the transgenics are a mix of genes of different species. Apparently speaking, transgenical food is the same, however, genetically speaking, they’re different from eachother despite the fact that the genes of the transgenes are the same in all transgenic. That happens because the place on the transgenics DNA where the intruders gene is put is not aways the same. The genetic engineering haven’t found a way to do that yet. Therefore, the consequences that these new DNA combinations might cause to our organisms are still unknown;
• That pests would evolve resistance to the supercrops and become “superpests”;
• That the transgenes would be transferred from crops to other plants and turn them into “superwheeds”;
• That the pesticides (insecticides, herbicides, and fungicides) used become stronger and stronger to fight pests, and pollute the water, the air, and the soil.
• That transgenes might ruin the integrity of native ancestral races of crops;
• That the transgenics monocultures might reduced biodiversity, because many fewer wild organisms are able to live in monocultures;
• That natural seeds might disappear, substituted by GM;
• That food supply might be dominated by a few large agrobiotech corporations that develop GM technologies. Those corporations would be Monsanto, Syngenta, Bayer CropScience, Dow, DuPont, and BASF;
• Much of the research into the safety of GM organisms is funded, overseen, or conducted by the corporations that stand to profit in their transgenic crops are approved by regulators.

Knowing about the possibilities of these problems, critics argue that we should procced with caution, adopting the precautionary principle, the idea that one should not undertake a new action until the ramifications of that action are well understood. In a few words, we could think of GM as a medicine, a medicine that might “cure” all our problems. However, if we look at the side effects on it’s package leaflet, well… they’re pretty bad…

People of different cultures have reacted differently to GM. European consumers have expressed widespread unease about possible risks of GM technologies, so their governments demand that GM food is labeled as such. In the US, however, consumers have accepted the crops approved by US agencies, and they don’t realize how much of their food contains GM products. Yet, there are still many things to be studied and thought… that’s polemic that has to be discussed.

Green Revolution

Green revolution is the introduction of industrialized agriculture to the developing world in the mid- and late- 20th century and it allowed the production of greater quantity and quality of food. This industrialization became necessary because people realized that farmers could not keep cultivating more land to increase crop output, than, agricultural scientists devised methods and technologies to increase crop output per unit area of existing cultivated land.

This new agriculture uses synthetic fertilizers and chemical pesticides; special types of grains that are more resistant to wind and diseases and produces high yields -transgenics; and heavy equipment powered by fossil fuels.

These developments had mixed effects on the environment. The use of already-cultivated land reduced pressure to convert additional natural land for new cultivation. As a matter of fact, between 1961 and 2003, food production rose 150%, population rose 100%, and the area converted for agriculture increased only 10%. Therefore, the green revolution prevented some degree of deforestation and habitat conversion when many countries were experiencing their fastest population growth rates.

However, there also are many negative sides that we must pay attention to:

• The intensive application of water, fossil fuel, innorganic fertilizers, and synthetic pesticides worsened pollution, and soil problems like erosion, salinization, and desertification;
• As monocultures made planting and harvesting more efficient, the increased output reduced biodiversity, because many fewer wild organisms are able to live in monocultures than in native habitats or amid tratitional small-scale polycultures;

• When all plants in a field are genetically similar as in monoculture, all are equally susceptible to viral diseases, fungal pathogens, or insect pests that can spread quickly from plant to plant. Therefore monocultures bring some risks of cataqstrophic failure;
• Many yields are declining in some regions because of the decline in soil quality from the heavy use of fertilizers, pesticides, and irrigation.

Green revolution and population

It is really important to understand the reason why the green revolution happened.

The transfer of technology to the developing world that marked the green revolution began in the 1940s, when US agricultural scientist Norman Borlaug introduced Mexico’s farmers to a specially bred type of wheat that produced large seed heads, was short in stature to resist wind, was resistant to diseases, and produced high yields. Within two decades of planting and harvesting this specially bred crop, Mexico tripled its wheat production and began exporting wheat. After this huge success, the wheat was taken to India and Pakistan, and soon, many developing countries were doubling, tripling, or quadrupling their crop yields using selectively bred strains of wheat, rice and corn, among others.

In the 1960s, India’s population, for instance, was skyrocketing and it’s traditional agriculture was not producing enough food to support the growth. By adopting green revolution agriculture, India sidestepped mass starvation. In the years since intensifying its agriculture, India has added several hundred million more people and continues to suffer widespread poverty and hunger.

Still, because of the huge problems brought by the green revolution, we can’t think of it as the solution of our food supplies problem. In fact, Borlaug  called his green revolution methods “a temporary success in man’s war against hunger and deprivation”.

Soil

Healthy soil is vital for agriculture, for forestry, and for the functioning of Earth’s natural systems. As a renewable resource, once depleted of it’s productivity, it may renew itself over a very long and slow time. We’ll reduce it’s ability to support life if we have careless or uninformed practices. 

Soil Characteristics

Soil characteristics vary from place to place, they’re defined basically by temperature and amount of rain. Soil in the Amazonian rainforest, in northern Brazil is less productive than the soil of temperate grassland in Kansas. This difference is due to the amount of rain that falls in the Amazon, because the water leaches minerals and nutrients from topsoil; also the warm temperatures speed the decomposition of leaf litter and the uptake of nutrients by plants, in a way that humus remain small in the thin topsoil layer.

Kansas prairie, in the other hand, has a lower rainfall, which means that the leaching is reduced and the nutrients remain within reach of plants’ roots. Plants return nutrients to the topsoil when they die, maintaining its fertility. The thick and rich topsoil of temperate grasslands can be farmed repeatedly with minimal loss of fertility if farming techniques like no-till and reduced tillage are used.

Therefore, most of the world’s soils are not ideal for agriculture, but that does not stop our world’s population to grow 80 milion people a year, which means that we are pressing lands into cultivation that are unsuitable for farming, which causes considerable damage to soil. Thw world loses anually 5-7 milion ha (12-17 milion ac), about the size of West Virginia.

Some consequences of careless use of the soil are:

• Erosion – removal of material from one place and its transport toward another by the action of wind or water. The arrival of eroded material at a new location is called deposition. Erosion and deposition are natural processes that help to create soil. Productive soils are produced by deposit of eroded sediment in river valleys and deltas by flowing water;

Even though erosion is a natural process, it becomes a problem for ecosystems and agriculture because it occurs more quickly than soil is formed and tends to remove the topsoil, which is the most valuable soil layer for living things. People have made fertile lands more vulnerable to erosion by overcultivating fields through poor planning or excessive tilling; overgrazing rangelands with more livestock than the land can support; clearing forests on steep slopes or with large clear-cuts.

Soil is protected from wind and water by grasslands, forests, and other plant communities. Vegetation breaks the wind and slows water flow. Plant roots hold soil in place and take up water. The removal of these plants accelerates erosion.

•  Overgrazilng – when sheep, goats, cattle, or other livestock graze on the open range, they feed on grasses. If the livestock population do not exceed a range’s carrying capacity and it does not consume grasses faster than they can be replaced, grazing may be sustainable. However, when too many animals eat too much of the plant cover, the plant regrowth is impeded and the replacement of biomass is prevented.

Overgrazing worsen damage to soils, natural communities, and the land’s productivity for grazing. All this happens because when livestock remove too much plant cover, soil is exposed and made vulnerable to erosion. Like I’ve said before, erosion makes it difficult for vegetation to regrow, in a way that the cycle of lack of cover provoking more erosion is perpetuated.

Another consequence is non-native weedy plants invasion. Plants that are less palatable to livestock may invade denuded soils and outcompete native vegetation in the new, modified environment. Overgrazing also compact soils and alter its structure. Compacted soil is hard for water to infiltrate, to be aerated, and for plants’ roots to expand or to conduct cellular respiration.

Overgrazing is a greater cause of  desertification. Humans keep a total of 3,4 billion cattle, sheep, and goats, and rangeland declaration is estimated to cost $23,3 billion per year.

 

• Clearing forests – is the cut of all trees in ane area. Clear-cutting is cost-efficient in the short term, however, has severe impacts on forest ecosystems. It may mimic natural disturbance events like fires, tornadoes or windstorms, and destroy or displace ecological communities, provoke soil erosion, and sunlight penetration to ground level might change microclimatic conditions, in a way that new types of plants replace those of the native forests; 

 

 

• Desertification – is the loss of more than 10% of productivity due to erosion, soil compaction, forest removal, overgrazing, drought, salinization, climate change, depletion of water sources, and other factores. Severe desertification can expand desert areas and create new ones in once-fertile regions. This has occured in areas of the Middle East, that have been farmed and grazed for long periods of time.

Desertification affects one-third of the planet’s land area and costs tens of billions of dollars a year for people in over 100 countries. A 2007 United Nations report estimated that desertification, worsened by climate change, could displace 50 milion people in 10 years. China loses $6.5 bilion annually. Desertification causes gigantic dust storms called dust bowl. 

 

• Dust bowl – erosion of millions of tons of topsoil by strong winds. It’s caused by the removal of native grasses and the break down of soil structures. They might travel up to 2,000 km (1,250 mi). In the 19th and early 20th centuries, homesteading settlers spread through Oklahoma, Texas, Kansas, New Mexico, and Colorado. Farmers grew wheat and ranchers grazed thousands of cattle, both on unsuitable land. In 1930, a drought exarcerbated the ongoing impacts and the dust storms begun. Some areas lost 10 cm (4 in) of topsoil in a few years.

These problems made the US government, the state and local government increase support for research into soil conservation measures. The Soil Conservation Service (SCS) was created and started to work with farmers to develop conservation plans for individual farms. The SCS teams include soil scientists, forestry experts, engineers, economists, and biologists. Nowadays, the SCS is called Natural Resources Conservation Service, and it serves as a model for similar efforts elsewhere;

 

• Salinization – buildup of salt in surface soil layers. It is more common in arid areas where precipitation is minimal and evaportion rates are high. This happens because of irrigation. Irrigation have allowed dry and unproductive regions into fertile farmland. However, overirrigation saturates soil with water in a way that waterlogging, when the water table rises to the point that water bathes plant roots, might occur. This is bad because it deprives the plant roots of access to gases and suffocates them.

Salinization occurs because if the area is to arid, the evaporation of water from the topsoil may pull water rich in dissolved salts upward through the soil from lower horizons. When the water evaporates at the surface, its salts precipitate, turning the soil surface white.

Salinization inhibits production of one-fifth of all irrigated cropland globally, and cost more than $11 billion a year. The best way to prevent it is avoid planting crops that require a great deal of water in areas that are prone to the problem. A second way is to irrigate with water low in salt content, since the irrigation water often contains some dissolved salt. And a third way is to irrigate efficiently, supplying no more water than the crop requires. These mesures minimize the amount of water that evaporates and hence the amount of salt that accumulates in the topsoil;

• Fertilizers – like overirrigation might result on salinization, overapplying fertilizers can cause chemical damage to soil with severe pollution problems. Plants require nitrogen, phosphorous and potassium to grow, altogether with other nutrients. These nutrients are removed from soil as the plants grow, and leaching likewise removes nutrients. If agricultural soils come to contain too few nutrients, crop yields decline, that’s when fertilizers are used. There are two main types of fertilizers, inorganic and organic. Organic fertilizers can provide some benefits that inorganic cannot. The proper use of these compounds improves soil structure, helps to retain nutrient and increase the water retaining capacity; erosion is prevented.

In order to prevent these consequences, there are agricultural techniques that can be used.

Impacts of Agriculture

Agriculture is the practice of raising crops and livestock for human use and consumption. It always  and it’s impacts on global environment have increased when Green Revolution began, around 1945. It’s environmental effects include:

• Alterations of the Earth’s hydrologic cycle;
• Increased levels of atmospheric greenhouse gases;
• Decreased biodiversity;
• Accelerated rates of soil erosion;
• Rapid spread of eutrophication in freshwater and marine ecosystems.

You can read more about these consequences here.

The human population has grown and so have the amount of land and resources given to agriculture, which currently covers 38% of Earth’s land surface. Most of our food and fiber are obtained from cropland, land used to raise plants for human use; and rangeland or pasture, which is land used for grazing livestock. The large-scale mechanization and fossil fuel combustion enabled farmers to replace horses and oxen with faster and more powerful means of working with crops and livestock. This was the agricultural revolution, and it allowed the increase of food production by intensifying irrigation; introduction of synthetic fertilizers; and the use of chemical pesticides reduced competition from weeds and herbivory by crop pests.

Modern industrialized agriculture enabled us to feed more people at a very high ecological price. Industrial agriculture can remove forests; destroy wetlands; turn grasslands to deserts; diminish biodiversity; encourage invasive species; pollute soil; air and water with toxic chemicals; and allow fertile soil to be blown and washed away.

Even though we  have more food to feed more people, political obstacles and inefficiencies in distribution makes 850 milion people in developing countries without enough to eat. In adition, although human population growth has sloewd, we can still expect our numbers to swell to 9 bilion by the middle of this century. Therefore, the kind of word we’ll live in then will depend on choices make now, and knowing  how to make food supply sustainable , maintaining healthy soil, water and biodiversity is one of them. Agricultural scientists and policymakers pursue a goal of food security, the guarantee of an adequate and reliable food supply available to all people at all times.

There are some farming techniques that can reduce the impacts of conventional cultivation on soils. Those are:

• Crop rotation – the type of crop grown in a field is alternated from one season or year to the next. This method can return nutrients to the soil, break cycles of disease associated with continous cropping, minimize erosion that might come from letting fielts lie fallow, and reduce insect pests, because if an insect is adapted to feed and lay eggs on one crop, planting a different type of crop will leave its offspring with nothing to eat. The crop rotation works if one of the rotated crops are legumes, because they have specialized bacteria on their roots, responsible for fixing nitrogen, revitalizing soil that the previous crop had partially depleated of nutrients;

• Contour farming - cultivation on slopes, even though water might erode the soil more easily. Farmers plow furrows sideways across a hillside, perpendicular to its slope and follow the natural contour of the land to help prevent formation of gullies;

• Terracing – the most effective method for preventing erosion, terracing consists on making levels platforms to contain water from irrigation and precipitation. It transforms slopes into series of steps like a staircase, enabling farmers to cultivate hilly land without losing huge amounts of soil to water erosion;

• Intercropping – also minimize erosion because it consist on planting different types of crops in alternating bands or other spatially mixed arrangements. Intercropping provides more ground cover and reduces vulnerability to insects and disease;

• Shelterbelts or windbreaks- used to reduce erosion from wind. Consists on the plantation of rows of trees or other tall, perenial plant along the edges or fields to slow the wind;

• No-till farming – a tractor pulls a “no-till drill” that cuts furrows through the topsoil and crop residue, drops seeds into the furrow, and closes it over the seeds. A dose of fertilizer might be added to the soil along with the seed.  

Environmental Health

Among many aspects, environmental health is the examination of the impacts of human-made chemicals on wildlife and people. It’s study and practice allows us to understand the environmental factors that influence human health and quality of life. People who work with it seek to prevent adverse effects on human health and ecological systems.

There are many different types of environmental health threat, or hazard, around us. Some of those are risks that we cannot avoid, however, there is also some amount of risk that can be avoided by taking precautions. Environmental health consists of taking steps to minimize the impacts of hazards and the risks of encoutering them. Here I’m going to talk a little bit about some of them, but focuse more on the chemical ones.

Physical hazards - are the natural hazard previously mentioned on the last post. Therefore, they are processes that occur naturally like earthquakes, volcanic eruptions, fires, floods, blizzards, landslides, hurricanes, and droughts, but they also include ongoing natural phenomena, like ultraviolet (UV) radiation from sunlight, which can cause skin cancer, cataracts, and immune suppression in case of excessive exposure.

Practices like increase our vulnerability to some physical hazards:

• Deforesting slopes makes landslides more likely;
• Channelizing rivers makes flooding more likely in some areas while preventing flooding in others. For more information about this, click here.

The risk over these practices can be reduced by improving our forestry and flood control practices; by choosing not to build in areas prone to floods, landslides, fires, and coastal waves. For hazards like exposure to UV light, the risk can be reduced by using clothing and sunscreen to shield our skin from intense sunlight.

Biological hazards - result from ecological interaction among organisms. They consist on bacterial or virus infection or other pathogeny. This is infectious disease, and they are also called communicable or transmissible disease. Infectious diseases like malaria, cholera, tuberculosis, and influenza are considered environmental health hazards. Like the other two types of hazards, it’s impossible to avoid risks from biological agents, however, steps can be taken to reduce the likelihood of infection.

Cultural or lifestyle hazards- result from the place we live, our socioeconomic status, occupation, or behavioral choices. Choosing to smoke cigarettes or living or working with people who do, increases our risk of lung cancer. Choosing to smoke is a personal behavioral decision, but exposure to secondhand smoke may not be under one’s control. The same thing can be said for drug use, diet and nutrition, crime and mode of transportation. Advocates of environmental justice argue that such health factors as living in proximity to toxic waste sites or working unprotected with pesticides might be correlated with socioeconomic deprivation.

Chemical hazards – include the many synthetic chemicals produced by our society like disinfectants, pesticides and the compounds that contribute to reproductive problems on animals. Chemicals produced naturally by organisms can also be hazardous.

Despite diseases like cancer, heart disease, and respiratory disorders have genetic bases, they are also influenced by environmental factors. Asthma, for instance, is influenced by genes, but also by environmental conditions. As a matter of fact, pollutants from fossil fuels combustion makes it worse. Children raised on farms suffer less asthma than those raised in cities.

Malnutrition can foster many different illnesses, just like poverty and poor hygiene. Lifestyle choices can affect risks of acquiring som noninfectious diseases, just like smoking can lead to lung cancer and lack of exercise, to heart disease. Infectious diseases are responsible for 26%, nearly 15 milion deaths, that occur worldwide per year. Some pathogenic microbes attack us directly, whereas other times infection occurs through a vector, which is an organism that transfers the pathogen to the host. When it comes to infectious diseases there is a gap between the number of deaths in developed nations and the developing countries; differences in hygiene conditions and access to medicine makes infectious diseases be responsible for almost half of all deaths in developings, while there are very few deaths in developed nations.

Even though public health efforts have lessened the impact of infectious disease in developed nations, some cases like the West Nile Virus, acquired immunodeficiency syndrome (AIDS), avian flu and influenza. Other diseases like tuberculosis and malaria are evolving resistance to antibiotics. There are also some tropical diseases like malaria, dengue, cholera and yellow fever that might expand into the temperade zone with global climate change. Also, habitat alteration can affect the abundance, distribution, and movement of certain disease vectors.

There are some cases in which chemicals are used to fight diseases, even though they’re also hazardous to our health. This happens in Africa, where the pesticide DDT is used to kill the mosquitos that transmit malaria, because they’re considered to be a health threat greater than DDT.

Curiosity:

It was only on the 60s that people began to learn about the risks of exposure to pesticides. The publication of Rachel Carson’s 1962 book, Silent Spring, was the key event that brought the pesticide dichlorodiphenyl-tricholoroethane (DDT) to public’s attention.

Synthetic Chemical

Synthetic chemicals are widely present in our environment, in fact, many of them have found their way into soil, air and water. A 2002 study by the US Geological Survey found that 80% of the US streams contain at least trace amounts of 82 wastewater contaminants, including antibiotics, detergents, drugs, steroids, plasticizers, disinfectants, solvents and perfumes, among other substances. The pesticides used to kill insects and weeds on farms, lawns, and golf courses are some of our most widespread synthetic chemicals. Because of this huge exposure, we carry traces of numerous industrial chemicals in our bodies.

Since not all synthetic chemicals pose health risks, and few are known as toxicants, we shouldn’t necessarily be alarmed. However, among the roughly 100,000 synthetic chemicals on the market today, few have been tested for harmful effects; therefore, we just do not know what are the effects, if any, so much different chemicals might cause to our organism.

Toxicants

Toxicants are not evenly distributed in the environment, and they move about in specific ways. Water, for example, carries toxicants from large areas of land and concentrates them in small volumes of surface water. Those chemicals that can persist in soil can leach down into groundwater and contaminate drinking water supplies. Many chemicals are soluble in water and enter organism’s tissues through drinking or absorption. That’s the main reason why aquatic animals like fish, frogs and stream invertebrates are effective indicators of pollution. Whenever scientists find low concentrations of pesticides exerting harm on frogs, fish, and invertebrates, they view this as a warning that people could be next. Toxicants might cause reproductive problems on animals and humans. 

The contaminants that wash into streams and rivers flow and seep into the water we drink and drift through the air we breathe.

The substances that can be transported by air makes the toxicological effect occur far from the site of direct chemical use. Airbone transport of pesticides is also called pesticide drift. This problem can be seen in the Central Valley of California, where irrigation, fertilizers and pesticides are used intensively. Dust particles containing pesticide residue and are transported by the wind for long distance and affected four species of frog in the mountains of Sierra Nevada.

Toxic agents may degrade quickly and become harmless, or may remain unaltered and persist for months, years or decades. The rate at the chemicals degradation depends on factors like temperatura, moisture and sun exposure, and how these factors interact with the chemistry of the toxicant. Those toxicans that persist in the environment have the greatest potential to harm organisms over long periods of time. In fact people are concerned about DDT and PCBs because of their long persistence time. 

There are natural toxicants that are also unhealthy and may cause us harm. However, scientists are still debating how much risk natural toxicants pose.