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TOPIC:
Environmental Problems
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ENVIRONMENTAL PROBLEMS
The air is always around us but we pay it little attention. It contains 78% nitrogen, 20% oxygen and 0.04% carbon dioxide and is essential for our lives.
Yet we do not seem to be too bothered about it and go on pumping all sorts of nasty things into it.
The atmosphere is a complex thing, which we do not realise is important to us. Recently we have begun to realise just how important one part of it is to us, the ozone layer.
The ozone layer
Ozone is a molecule made up of three oxygen atoms:
The oxygen molecules present in air has only 2 oxygen atoms in it. So what is so different about ozone?
If you go up to 12-30 miles above the Earth's surface you find a layer of air which contains small amounts of ozone gas. The ozone molecules absorb the ultraviolet (UV) rays that are emitted from the Sun and which are dangerous to all living things. UV rays can increase the risk of
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So ozone gives us a protective blanket high above us that reduces the amount of UV rays that get through to the Earth's surface. Therefore ozone helps protect us.
However the atmosphere's protective effect is under threat from things we do.
CFC's
CFC's are "Chloro-fluoro-carbons" to their friends. Although nowadays they
don't have many friends.
We thought that they were great molecules at one time. They used to do
useful things like running cool machines such as 'fridges' and air-conditioning units. They were in aerosols and polystyrene foam.
However, we now know that they break up ozone molecules and so destroy the layer that protects us from UV rays from the Sun. Not a good idea!
In the last few years we have realised that there are huge holes in the ozone layer near the North and South poles - and they have grown! As more nasty UV rays flood through more people are developing skin cancer.
CFC's have been banned in many countries and alternatives are used instead, but these can be expensive.
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This diagram shows renewable and fossil fuels:
We all burn fossil fuels. We do it directly by burning coal or driving cars. We also indirectly burn fossil fuels when we use electricity generated using them.
Our cars and power stations are responsible for most of the fossil fuel burning. The gases released include carbon dioxide, sulphur
dioxide and oxides of nitrogen (NO2, NO3, etc.). Up in the atmosphere these
gases are dissolved in water and cause acid rain.
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Leaded petrol
Not only do our cars burn a fossil fuel but the older "4 star" petrol contains the element lead.
This leaded petrol was used because it made engines run smoothly. But when it was burned it released the lead into the air. When breathed in it could damage our nervous system. Not nice.
Thankfully, more modern engines can burn "lead-free" petrol and so there will be less lead in the air.
The Green House Effect
What is it?
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The atmosphere becomes clogged up with "greenhouse gases" such
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This is just how the glass on a greenhouse works. So the inside of the greenhouse gets warmer and warmer over time.
In the case of the Earth the warming up has happened very slowly over decades and centuries. However the levels of greenhouse gases have risen sharply recently.
What might be the effects?
As the temperature of the Earth increases it is predicted that we will see changes in weather patterns, including drought and flooding.
The Polar ice caps may melt and so produce raised sea levels. Low-lying areas will be flooded including many major cities.
What may cause it?
Carbon dioxide and methane are thought to be "greenhouse gases". But how are they produced?
Carbon dioxide
Normally there is a balance in the amount of carbon dioxide in the
atmosphere. It is produced by respiration and used up in photosynthesis. So across the whole planet there is a beautiful balance as part of the "carbon
cycle".
However, as we have cut down trees for farming land, fuel and timber we reduce the number of plants that can carry out photosynthesis. This
'deforestation' results in less carbon dioxide being cleared from the atmosphere.
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All this burning results in even more carbon dioxide being produced. Levels have risen by about 20% already and are still increasing - and doing so even more quickly!
More carbon dioxide is being produced and less cleared away.
We are slowly suffocating ourselves!
Methane
The other common greenhouse gas is methane. Its molecules have one carbon and four hydrogen atoms.
Marshland and bogs produce methane naturally. It bubbles up from
decaying plant material.
However, increasing amounts are produced through agriculture. The two main ways are in rice production (paddy fields) and cattle rearing. It seems that cows pass wind each day, just like us, but in greater volume.
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Rainfall is naturally acidic. Carbon dioxide reacts with water vapour in the atmosphere to produce weak carbonic acid. This is enough to give rainfall a typical low acidity of between 5-6 pH (where 7 is neutral). By itself this can account for chemical weathering of carbonate-based rocks (chalk and
limestone) over time.
The Causes of Acid Rain
Human activity has resulted in greater acidity of rainfall and more
widespread impacts over shorter time periods. The release of large quantities of sulphur dioxide and nitrogen oxide into the atmosphere, largely as a result of burning fossil fuels, has resulted in reactions with water vapour to produce much stronger acidity in rainfall (pH of 3 and 4) and precipitation (rain
and/or snow) being the chemical equivalent of sulphuric acid and nitric acid.
The most significant contributors of sulphur dioxide and nitrogen oxide in the past 80 years have been:
• Coal-fired power-stations
• Rapid industrialisation in newly emerging economies burning coal and oil.
• The rise in car production, ownership and use.
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International Scale of Acid Rain
Whilst the contributing gases to acid rain are generated in urban, industrial centres, the effects of acid rain are often experienced hundreds, if not
thousands, of miles away from the pollution source. The action of prevailing winds distributes the atmospheric pollutants downwind so that when the resultant acid rain/snow falls, it is affecting different territory in, often, different countries.
The international scale of this problem makes it difficult to attribute blame to any one particular source area or get source countries to accept responsibility for their emissions. Norway, for example, receives over 90% of its sulphur deposition from other countries, but that may be from Britain, northern France, Germany or Poland depending on the wind direction.
The Effects of Acid Rain
If rain or snow falling onto ground, buildings or into lakes is highly acidic, the chemical impacts can have rapid and widespread consequences:
• Building stone weathers faster – particularly older monuments
constructed of limestone and chalk. Cathedrals and minsters, such as York Minster, require more regular, expensive, renovation of
weathered stone, and the Taj Mahal in India is experiencing similar problems as a result of India’s rapid emergence as an industrial power.
• Forests can be decimated as roots are highly sensitive to acidity of water. The fine nutrient-absorbing rootlets are damaged, weakening growth and opening the tree up to infection and disease. Over 50% of forests in the Netherlands are reported to have been damaged by acid rain. In countries where the production of timber is a significant export, such as Canada, any damage affects the economy as well as the
environment.
• A secondary consequence, as forests decline, is that habitat and the forest ecosystem suffer. Plants and animals that depend on the forest cover reduce in number.
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accumulated over the winter. This can be particularly damaging to young immature fish or ‘fry’. Many salmon rivers and lakes of
Scotland and Canada have seen significant falls in salmon stock that is attributed to the effects of raised acidity of the water.
• Human health may be affected if acidity in the water increases
corrosion of water pipes. Swedish health consultants traced the cause of intestinal discomfort and ‘green hair’ amongst children in rural parts of Sweden in the 1980s to rapid corrosion of copper pipes supplying water to older properties.
Responding to Acid Rain
In affected regions:
• Lime (crushed limestone) has been spread over the surface of lakes to neutralise the acid in Scotland and Canada. Lime is alkali.
• Copper pipes have been replaced by plastic piping delivering water to homes in Scandinavia.
In source regions:
• International agreements since the 1970s have resulted in cuts in emissions of contaminants and polluting emissions, particularly in Europe and North America. The European Union has been a major driver in seeking agreement amongst member countries to reduce sulphur dioxide and nitrogen oxide emissions since 1979. In 1988 an EU directive required power stations to reduce emissions – in the UKs case, by 60% in sulphur dioxide and 30% in nitrogen oxide. This is achieved in part by lining chimney flues with limestone to neutralise the acidic gas emitted (flue-gas desulphurisation), partly by subsidising power-stations to change to low-sulphur coal, and by encouraging the growth of gas-fired power-generation, subsidising sustainable,
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International Assessment of Acid Rain
The areas suffering the worst effects of acid rain emerged in the 1970s and ‘80s in NE North America and Central, Eastern and Northern Europe.
International transboundary emission agreements since then have been largely effective in significantly reducing sulphur and nitrogen emissions and reducing the scale and impact of acid rain degradation. The problem has not been solved, but by contributing countries agreeing to strict emission
reductions the issue is less severe than in the latter decades of the twentieth century.
The current focus for acid rain action is in Asia where the rapid
industrialisation of India, China and neighbouring nations has seen the rapid expansion of coal-fired power stations and direct burning of high-sulphur-content coal by industry. Compounded by the continuing growth of Asian megacities and the rapid rise in car ownership, the challenge for dealing with the consequences of acid rain has shifted firmly to the Newly Industrialising
Countries (NICs) of Asia.
More Solutions
Another solution is to basically produce less greenhouse gases.
To do this we well need to use less fossil fuel. This includes our use of materials and power that rely on them.
In addition to this we can reduce the amount released from source, that is to remove the gases before they are released.
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Overpopulation occurs when there are more people than the land can
sustain.
What is Overpopulation?
Overpopulation is an undesirable condition where the number of the existing human population exceeds the actual carrying capacity of Earth.
Overpopulation is caused by a number of factors. Reduced mortality rate, better medical facilities, depletion of precious resources are few of the causes which result in overpopulation. It is possible for a sparsely populated area to become densely populated if it is not able to sustain life.
Growing advances in technology with each coming year has affected
humanity in many ways. One of these has been the ability to save lives and create a better medical treatment for all. A direct result of this has been the increased lifespan and the growth of the population.
According to Wikipedia,
“Overpopulation occurs when a species’ population exceeds the carrying
capacity of its ecological niche. It can result from an increase in births (fertility rate), a decline in the mortality rate, an increase in immigration, or an unsustainable biome and depletion of resources.”
In the past fifty years or so, the growth of the population has boomed and has turned into overpopulation. In the history of our species, the birth and death rates have always been able to balance each other and maintain a population growth rate that is sustainable.
Since the time of the Bubonic Plague in the 1400s, the growth of the
population has been on a constant increase. Between the time of the plague and the 21st century, there have been hundreds and thousands of
wars, natural calamities, and man-made hazards.
However, none of these could make a dent on the population. Developing nations face the problem of overpopulation more than developed countries, but it affects most of the Earth as of now. When we are talking about
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Various Causes of Overpopulation 1. The Decline in the Death Rate
At the root of overpopulation is the difference between the overall birth rate and death rate in populations. If the number of children born each year equals the number of adults that die, then the population will stabilize.
Talking about overpopulation shows that while there are many factors that can increase the death rate for short periods of time, the ones that increase the birth rate do so over a long period of time.
The discovery of agriculture by our ancestors was one factor that provided them with the ability to sustain their nutrition without hunting. This created the first imbalance between the two rates.
2. Agricultural Advancements
Technological revolutions and population explosions occur at the same time. There have been three major technological revolutions. They are the tool-making revolution, the agricultural revolution, and the industrial revolution.
Agricultural advancements in the 20th century have allowed humans to increase food production using fertilizers, herbicides, and pesticides and yields further. This allowed humans with more access to food that leads to subsequent population explosions.
3. Better Medical Facilities
Following this the industrial revolution started. Technological advancement was perhaps the biggest reason why the balance has been permanently disturbed.
Science was able to produce better means of producing food, which allowed families to feed more mouths. Besides, medical science made many
discoveries, thanks to which they were able to defeat a whole range of diseases.
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means of mortality tipped the balance and became the starting point of overpopulation.
4. More Hands to Overcome Poverty
However, when talking about overpopulation, we should understand that there is a psychological component as well. Poverty is considered as the leading cause of overpopulation. In the absence of educational resources, coupled with high death rates, which resulted in higher birth rates, that is why impoverished areas are seeing large booms in population.
For thousands of years, a very small part of the population had enough money to live in comfort. The rest faced poverty and would give birth to large families to make up for the high infant mortality rate.
Families that have been through poverty, natural disasters, or are simply in need of more hands to work are a major factor for overpopulation.
As compared to earlier times, most of these extra children survive and consume resources that are not sufficient in nature.
According to the UN, the forty-eight poorest countries in the world are also likely to be the biggest contributors to population growth. Their estimates say that the combined population of these countries is likely to increase to 1.7 billion in 2050, from 850 million in 2010.
5. Child Labor
It is no less than a tragedy that child labor is still in practice extensively in many parts of the world. As per the UNICEF, approximately 150 million children are currently working in countries having few child labor laws. The children being seen as a source of income by impoverished families begin work too young and also lose the educational opportunities reflected, particularly when it comes to birth control.
6. Technological Advancement in Fertility Treatment
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Today there are effective medicines that can increase the chance of conception and lead to a rise in the birth rate. Moreover, due to modern techniques, pregnancies today are far safer.
7. Immigration
Many people prefer to move to developed countries like the US, UK, Canada, and Australia, where the best facilities are available in terms of medical, education, security, and employment. The result is that those people settle over there, eventually making those places overcrowded.
If the number of people who are leaving the country is less than the number of people who enter, it usually leads to more demand for food, clothes, energy, and homes.
This gives rise to a shortage of resources. Though the overall population remains the same, it just affects the density of the population, making that place simply overcrowded.
8. Lack of Family Planning
Most developing nations have a large number of people who are illiterate, live below the poverty line, and have little or no knowledge about family planning. Besides, getting their children married at an early age increases the chances of producing more kids.
Those people are unable to understand the harmful effects of overpopulation, and lack of quality education prompts them to avoid family planning
measures.
9. Poor Contraceptives Use
Poor family planning on the part of partners can lead to unexpected pregnancies though contraceptives are easily available in developed countries.
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shows that this figure drops to 43% in underdeveloped countries, which leads to higher birth rates.
Fatal Effects of Overpopulation
1. Depletion of Natural Resources
The effects of overpopulation are quite severe. The first of these is the
depletion of resources. The Earth can only produce a limited amount of water and food, which is falling short of the current needs.
Most of the environmental damage seen in the last fifty-odd years is because of the growing number of people on the planet. They include cutting down forests, hunting wildlife in a reckless manner, causing pollution, and creating a host of other problems.
Those engaged in talks about overpopulation have noticed that acts of
violence and aggression outside of a war zone have increased tremendously while competing for resources.
2. Degradation of Environment
With the overuse of coal, oil, and natural gas, it has started producing some serious effects on our environment. Besides, the exponential rise in the number of vehicles and industries has badly affected the quality of air.
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3. Conflicts and Wars
Overpopulation in developing countries puts a major strain on the resources it should be utilizing for development. Conflicts over water are becoming a source of tension between countries, which could result in wars. It causes more diseases to spread and makes them harder to control.
Starvation is a huge issue that the world is facing, and the mortality rate for children is being fuelled by it. Poverty is the biggest hallmark we see when talking about overpopulation.
All of this will only become worse if solutions are not sought out for the factors affecting our population. We can no longer prevent it, but there are ways to control it.
4. Rise in Unemployment
When a country becomes overpopulated, it gives rise to unemployment as there are fewer jobs to support a large number of people. The rise in
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5. High Cost of Living
As the difference between demand and supply continues to expand due to overpopulation, it raises the prices of various essential commodities,
including food, shelter, and healthcare. This means that people have to pay more to survive and feed their families.
6. Pandemics and Epidemics
Poverty is linked to many environmental and social reasons, including
overcrowded and unhygienic living conditions, malnutrition and inaccessible, inadequate, or non-existent health care, for which the poor are more likely to be exposed to infectious diseases. Further, high densities of population
increase the chance of the emergence of new pandemics and epidemics.
7. Malnutrition, Starvation and Famine
When the availability of resources is scarce, starvation, malnutrition, along with ill health and diseases caused by diet-deficiency such as rickets become more likely.
Famine is typically associated with less-developed regions, and there is a high correlation with poverty levels.
8. Water Shortage
Roughly 1% of the world’s water is fresh and accessible. Overpopulation is a major issue that creates immense pressure on the world’s freshwater supplies. As per the study, the human demand for freshwater would stand at
approximately 70% of freshwater available on the planet by 2025. Therefore, people living in impoverished areas that already have limited access to such water will be at great risk.
9. Lower Life Expectancy
A large proportion of the world’s population growth occurs in less developed countries. Therefore, lower life expectancy caused by the booms in
population is experienced by less-developed nations.
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10. Extinction
The impact of overpopulation on the world’s wildlife is severe. As demand for land grows, the destruction of natural habitats, such as forests, becomes common.
Data has also been collected to show a direct link between increases in human population and decreases in the number of species on the planet. If present trends continue, as many as 50% of the world’s wildlife species will be at risk of extinction, some scientists warn.
11. Increased Intensive Farming
With the growth of population over the years, farming practices have evolved to produce enough food required to feed a larger number of people. However, this intensive farming methods cause damage to local ecosystems and the land that may pose problems in the future.
Furthermore, intensive farming is also contributed to climate change due to the machinery required. If the population continues to grow at its current rate, this effect will likely intensify.
12. Faster Climate Change
Overpopulation forces larger nations, like China and India, to continue to develop their industrial capacities. They now rank as two of the three largest contributors to emissions in the world, other than the United States.
According to 97% of the scientific community, human activities are changing global temperatures. If more is not done to reduce individual carbon
footprints on a wide scale, larger populations may speed these changes up. Incredible Solutions To Overpopulation
1. Better Education
One of the first measures is to implement policies reflecting social change. Educating the masses helps them understand the need to have one or two children at the most.
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Family planning and efficient birth control can help in women making their own reproductive choices. Open dialogue on abortion and voluntary
sterilization should be seen when talking about overpopulation.
2. Education for Girl Child
Currently, over 130 million young women and girls around the globe are not enrolled in school. The majority of these live in male-dominated societies, particularly in sub-Saharan Africa and South and West Asia, that does not give women equal right to education as men.
Entrenched gender norms and child marriage further disrupt their access to education. The girl who receives less education is more likely to have children early and vulnerable to exploitation. Moreover, impoverished families are less likely to enroll their female children in school.
3. Making People Aware of Family Planning
As the population of this world is growing at a rapid pace, raising awareness among people regarding family planning and letting them know about serious after-effects of overpopulation can help curb population growth.
One of the best ways is to let them know about various safe sex techniques and contraceptive methods available to avoid any unwanted pregnancy.
4. Tax Benefits or Concessions
The government of various countries might have to come up with various policies related to tax exemptions to curb overpopulation.
One of them might be to waive a certain part of income tax or lowering rates of income tax for those married couples who have single or two children. As we humans are more inclined towards money, this may produce some
positive results.
5. Knowledge of Sex Education
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Mostly, the information is incomplete, which results in sexually active teenagers unaware of contraceptives and embarrassed to seek information about the same. It is, therefore, important for parents and teachers to shed their old inhibitions and make their kids or students aware of solid sex education.
6. Social Marketing
Social marketing has already been started by some societies to educate the public on overpopulation effects. The intervention can be made widespread at a low cost. A variety of print materials (flyers, brochures, fact sheets,
stickers) can be distributed in places such as at local places of worship, sporting events, local food markets, schools and at car parks.
A lower death rate is a good thing. Modern medicine and farming
techniques have allowed us to reduce deaths through starvation and disease.
However the birth rate has increased alarmingly. It has resulted in population rises that are out of control, many of these are in so-called 'under-developed' countries.
The results
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As the poorer, under-developed countries become more industrialised they use more of their limited resources for their growing populations. They want to provide all the essentials such as health care and education.
These growing economies demand more energy from fossil fuels, adding to the pollution problems.
Deforestation is increased to provide building land, timber and farmland.
This includes the essential rainforests. Areas the size of Wales are lost each year.
Mining and other extraction techniques lead to reduced mineral reserves.
But these effects include us too. Our demand for materials and energy is much greater than under-developed countries. They just want what we want. They have that right, don't they?
We want new things and to run all our equipment - including computers!
Overpopulation is a global problem - but it is also personal.
The solution
At this present rate there will be many billions of people trying to live in smaller and smaller areas, fighting for fewer and fewer resources.
Not a great vision of the future is it!
We must do something. But what?
Encouragingly, a lot of time has been spent over recent years into examining what might be done. Some countries have introduced strict birth control laws. China has even made it illegal to have more than one child!
Education, including about contraception and birth control is another key
measure. This has been shown to help to reduce the birth rate in a population.
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Farming
Farming is often under-rated nowadays. Modern farming practices have radically increased the efficiency of farming, producing more food from the available land.
In a lifetime we have moved from not having enough to eat to having tons of food.
Despite this "intensive farming" providing us with masses of cheap
food there are a number of problems.
Effects on animals
Strain can be placed upon domestic animals so that they produce the best possible food yield for us. Examples include the confinement of battery
hens and veal calves.
Food chains are damaged by the use of pesticides to kill insects and animals
that could damage crops. The chemicals used are indiscriminate, they kill any insect. So the links in food chains are wiped out and whole communities of animals can suffer.
Fields that are intensively farmed contain only single crop species, and the crowd of plants, insects, animals and birds that used to exist there are gone. Some face extinction.
Deforestation
Deforestation is the loss of trees due to demand for timber, land and so on.
It doesn't just occur in rainforests, the deforestation happens here too. We have virtually deforested our whole country over centuries, including our hedgerows.
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What are the effects of deforestation?
There are 4 main effects:
1. Decrease in rainfall:less trees means less transpiration and photosynthesis. 2. Soil erosion: the exposed soil dries out under the Sun.
3. Serious flooding: rainwater runs off the exposed soil rather than soaking in as before.
4. More carbon dioxide: the trees that used to remove the gas are gone.
The problem gets worse and worse.
How does what we buy link in to deforestation?
Bioaccumulation
Pesticides are used to kill animal pests, and herbicides are used to kill
weeds.
Both can be useful types of chemicals. However, their use has problems.
One problem is "bioaccumulation". These chemicals are poisonous to other animal life. If the animals at the start of a food chain take up small amounts it becomes more and more concentrated higher up until it can kill the animals at the top - including humans.
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Eutrophication
Eutrophicationis what happens when too much chemical fertiliser is used
on crops and it washes into rivers and streams.
The nitrates in the fertilisers are essential to get crops to grow well and increase yields.
However, if too much is used, or it rains soon after it is added to fields, the fertiliser gets washed away. The nitrates then help plants in the rivers and streams to grow very quickly, especially algae.
But after the initial massive growth in algae there isn't enough light and for them all and a lot of the algae die.
All those dead plant start to decay. You are left with a green and slimy mess. This removes oxygen from the water and kills fish and other animals. Then even more algae and animals die.
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The bottom line with all these problems with modern, intensive farming is that to change will be very expensive.
Farming and the environment often seem to clash. But it is possible to produce our food without destroying the Earth.
We have to realise that "traditional farming" techniques will work but will give us poorer yields. Food will therefore be more expensive.
But it will mean that we can treat animals better and recreate a "balanced
ecosystem", which will continue to produce our food year after year - that is
be sustainable.
Surely it must be worth spending that bit more money?
Organic farming
Organic farming is a phrase often used to describe traditional farming
practices.
It is becoming increasingly used and with scientific knowledge it is more efficient that it used to be but without being intensive.
There are three main areas included in organic techniques:
1. Using organic fertilisers
The faeces of farm animals such as cows contain lots of useful nitrates. Spreading this useful 'muck' back onto fields saves using chemical fertilisers.
2. "set-aside" By replanting trees (reforestation) and allowing the ground to lie uncultivated, erosion of the soil is prevented and the amount of mineral ions in it can recover after each crop.
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biological pest control
even buy or rent hedgehogs to use now!
Fish farming
Many fish farms have been set up in Scotland and Norway as an attempt to stop relying on North Sea oil too heavily.
Their basic design is the same. A large cage or net is floated in a
sea-loch or fjord, that is a narrow sea-inlet.
Salmon are grown from artificially fertilised eggs kept in aquarium tanks.
When they are large enough they are released into the nets in the sea-loch.
The salmon can swim around inside the cages but cannot escape outside. This together with the large number of fish =restricts their movement. This
smaller movement maximises the energy transfer from their food into putting on weight.
The fish are fed a carefully controlled diet of food pellets. If too much is given it falls through the net and is wasted on the floor of the loch. This wasted food and their faeces can pollute the water, so the nets are sometimes moved around within the loch.
In the nets the salmon are protected from their natural predators
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lice". One way to treat these is to use an insecticide called Dichlorvos.
Another, is to put another type of fish called wrasse in with the salmon. The wrasse feed on the salmon's fish lice and keep them clean. This is a good example of biological pest control.
Biological pest control
Biological pest control includes any example where an animal is chosen
which will eat the pest species.
Advantages over using chemical pesticides:
1. It can be cheaper.
2. There are no concerns about using too much and damaging the environment. 3. You can be specific about which things you kill, rather than just killing every
insect including the useful ones.
4. You can sell edible plants and crops without having to worry about pesticide residues inside them.
The only disadvantage is that you never get rid of all the pests but instead after a couple of years the number of pests will have fallen to an acceptable, lower level.
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Notice that in the end, a gentle, undulating pattern develops between the numbers of pests and predators with far fewer pests around.
Greenhouses
Greenhouses are great. They let plants grow in nice, warm, sheltered conditions.
As the Sun's rays shine in they warm up because the heat cannot get out as quickly as it comes in. Closing the windows during the day helps
to raise the temperature, humidity and carbon dioxide levels. You can change the light at night time too.
All of this helps to speed up photosynthesis and the growth of the plants.
However, there are many pests, which affect greenhouses and just love those nice conditions.
The four main pests are:
1. Aphids. 2. Whitefly. 3. Mealy bugs. 4. Red spider mites.
What could we do about them?
We could just blast them with chemical pesticides. But that would kill all the useful worms, ladybirds and bees. It would also stay around in the soil and our crop.
A better way is to use specific predators against each one, that is, use biological pest control.
Pest: Biological control:
What the predator does:
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Mealy bugs Ladybird One type of ladybird attacks and eats them.
Whitefly Encarsia This tiny wasp lays its eggs inside the
whitefly so that the larvae can eat their way out. Nice!
Red spider mites
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