INTRO
As many of you may recall, in our last presentation we discussed the theme Environmental Issues focusing mainly on air pollution, water pollution and the climate change as a whole. However, in this project we will only be discussing one of the subtopics of said presentation. Some of you may remember this graphic we showed you in our last presentation. It shows us the greenhouse emissions on the United States and as you can see, transportation is the biggest contributor to these emissions in the US and also has major impact on the rest of the world, and this will be our focus on this presentation, more specifically, what could be a solution for it. Before I say anything else, do any of you remember any of the solutions we gave you for this issue? Maybe you guys might even know some other solutions we didn´t refer to. Anyone?
Yes, one of the solutions we presented was indeed the change from fuel-based cars to cars that run on renewable energies, and that is exactly our focus for this presentation. Today, we will be showing you the main concepts and laws that you need to know to hopefully understand how batteries and electric motors work and we will be talking about a certain electric car model which many of you may know, the Tesla model S. A quick note, we chose this car specifically for some reasons. One of them being that there are many other electric cars out there that work in a somewhat different way and due to the time limit we would not be able to present any other models, another reason is that the Tesla company is well-known and the worldwide leader in electric vehicle sales AND is the most valuable carmaking company since July 2020, and the last reason being that we like Elon Musk, but anyways…
One other thing before I give my colleagues the freedom to tell you about electric cars, we as a group need you to understand something. This presentation won´t necessarily have an end, just like our Environmental Issues presentation. In this presentation we will only show you the theory behind how everything works, and in the text term we will hopefully be able to transit from the theory side of the project to the practical side of it.
Since we will be talking about eletric cars, there is a type of battery that is commonly used in these cars, this being the lithium-ion battery, which will be presented by my colleague Fábio. n 1786, the Italian anatomist Luigi Galvani was dissecting a frog and noticed that each time his assistant touched the frog with his scalpel, the frog's muscles would contract. This would happen every time the frog's tissue was touched with 2 metals in 2 different spots. From that point on, Galvani defended his theory that said that metals were just electricity conductors and that the electricity would be stored in the animal's muscles waiting to be released. However, his theory was proven wrong by Alessandro Volta, who developed many experiments and finally came to realize that whenever the metals that touched the animal were the same, there weren't any contractions happening, and therefore came to the conclusion that it weren't the animal muscles that had electricity in them, the electricity was contained in the metals and the animal's muscles would be a path for the electricity to flow. To prove his theory, Volta created a circuit made of 2 diffferent metallic electrodes and a solution of dissolved ions, usually called an electrolytic solution. The electrolytic solution would be put inbetween the 2 metallic electrodes. This sequence would then be repeated a few times and would be placed around a vertical stem, therefore connecting every sequence. With this, Volta also realized that different metals would generate different ammounts of current. An example of this kind of batteries is shown in this picture I found. Looks at image This battery is made out of Zinc plates, Silver plates and some blotting paper soaked in what could be for example a solution of Sulfuric Acid. You can also see what an individual segment of the battery looks like right here points at image, once again, made out of 2 different metals and 1 electrolytic solution.
Lithium-ion batteries power the lives of millions of people each day. From laptops and cell phones to hybrids and electric cars, this technology has grown in popularity in the last few years due to its lightweight, high energy density, and ability to recharge.
So how does it work?
A battery is made up of an anode, that is generally made of carbon(graphite), a cathode, typically made from a chemical compound called lithium-cobalt oxide (LiCoO2) or, in newer batteries, from lithium iron phosphate (LiFePO4), a separator, that blocks the flow of electrons inside the battery, an electrolyte, a conductive ionic liquid that varies from battery to battery, and two current collectors (positive and negative).
The anode and cathode store the lithium, the electrolyte carries positively charged lithium ions inside the battery through the separator. When the ions are released from the anode to the cathode, the battery is discharging and providing an electric current. If it works the other way around, the battery is charging, and the energy supplied by the charger sends the lithium ions from the cathode to the anode.
When discharging, the movement of the ions creates electrons in the anode that creates a charge at the negative current collector, creating an electrical current that then flows from the current collector through a device being powered to the positive current collector. When charging, the opposite happens.
The movement of ions and electrons are interconnected processes, and if one stops so does the other. This can happen if the battery is completely discharged or if you just switch off whatever the battery is powering.
When the battery is completely discharged, the ions stop moving through the electrolyte. Therefore, electrons can't move through the outer circuit either—so you lose your power.
If you switch off whatever the battery is powering, the flow of electrons stops and so does the flow of ions, stopping the discharge of the battery at high rates. It does not mean that the battery will stop discharging, but it will at a very slow rate...
Unlike simpler batteries, lithium-ion ones have built in electronic controllers that regulate how they charge and discharge. They prevent the overcharging and overheating that can cause lithium-ion batteries to explode in some circumstances.
Lithium-ion batteries in electric cars
A battery in an electric car is connected to one or more electric motors, which drive the wheels. When you press the accelerator the car instantly feeds power to the motor, which gradually consumes the energy stored in the batteries.
A typical 40kWh battery pack from a mainstream electric car might be enough to power it for 240 kilometers or more, while Tesla's biggest 100kWh battery is good for around 600 kilometers
These batteries are recharged by a designated EV charging socket. These are rated in kW from about 3kW up to about 50kW - or 120kW on Tesla's supercharger network that you can find in some roads. The higher the rating, the quicker they will restore your EV's range. At a home or workplace, these sockets are either 3kW 'slow' units, or 7kW 'fast' chargers capable of recharging an EV in 6-12 hours.
It is normally said that a battery on an electric car is a proven technology that will last for years, and even car manufacturers confirm it. For example, Nissan and Tesla warrant that their electric car batteries will last eight years or 160,000 kilometers. This might seem impressive since mobile phones start to wear after just a couple of years, but this is due to being fully charged and discharged hundreds of times. In an electric car, it's not good enough for a car designed to last many thousands of kilometers, so EV manufacturers go to great lengths to make electric car batteries last longer, by for example “buffering” where drivers can't use the full amount of power they store, additional spare capacity to compensate for degradation over time, reducing the number of cycles and some clever cooling systems like Tesla, in which it is used liquid glycol as a coolant. The system takes this heat to a refrigeration cycle and use electric resistance heating in cold conditions. This coolant is distributed throughout the pack to cool the cells. But considering that every Tesla has a lot of cells to cool, this is a challenge. To get over this challenge, Tesla has a system that is based on a ribbon shaped metallic cooling tube that snakes through the pack.
But what happens if the battery reaches its retirement age? When batteries do reach the end of their working life, they can be:
Advantages
Disadvantages
It is important to leave a disclaimer before I continue: we will be not comparing these batteries with other types of batteries but with gasoline.
We will now talk about the physics on an electric car.
One interesting thing that we found while doing our research is the difference between the word engine and motor. First of all is there a difference for you?
Now the words are commonly used to mean the same however the difference is that engines are a device used to create movement by the combustion of something while motors run on electricity to create movement.
Knowing that we are talking about electric cars you can guess which of these 2 terms we will be using and that is motors.
Motors can be divided in 2 different categories, AC motors and DC motors. There are other things which differentiate them but essentially AC motors are powered by alternating current and DC motors are powered by direct current. It was already explained in other presentations but just to not leave it in blank we will briefly explain the difference between ac and dc current.
In AC current as the name states the electrons flow direction is alternated/changed periodically reversing the polarity of the circuit. By connecting an oscilloscope to an AC circuit, we can see its waveform. As shown in this graph, this would be one of the waveforms we expect on an AC circuit and we can see in fact that the voltage is reversed throughout time hitting its maximum and minimum in every completed period.
And in a DC current unlike an AC current the electrons have a constant flow, thus having a constant voltage. Again, here we have what an oscilloscope would show us when connected to a DC circuit, as you see it’s just a straight line as again the voltage is constant. (this would be a 1.5V battery)
When it comes to AC motors there are many variants but as said earlier, we will only be talking about tesla cars and their models use induction motors which is what we will be explaining.
An induction motor is an alternate current electric motor where the electric current in the rotor needed to produce torque is obtained by electromagnetic induction from the magnetic field of the stator winding.
The first ever AC motor was created by Nikola Tesla. After dropping out of university and gambling his fortune away, Thomas Edison hired Nikola Tesla to work for him. Tesla caught Edison´s attention with his incredible work and offered him 50.000$ if he could improve Edison´s DC dynamos design. At the time, Alternate Current was believed to be extremely dangerous to handle, and therefore he turned down his offer. Tesla moved on and not long after this happened, he took his design to the American Institute of Electrical Engineers and George Westinghouse was intrigued and approached Tesla offering him 65.000$ for his patent, 15.000$ more than what he had asked for. With this, Westinghouse was one of the first pioneers of alternating current systems.
Now that you know a little bit more about Nikola Tesla’s past and the history behind the invention of the first induction motor, I will also be making a brief introduction about the main laws behind the induction motor and what it makes it work.
The first thing I will be talking about is the Oersted experiment, which was developed by Hans Christian Oersted that showed that there was a connection between electricity and magnetism. He proved this by showing that whenever a current was switched on through a wire, it made a compass needle turn so that it would be positioned perpendicularly to the wire. This would prove that the current had produced a magnetic field strong enough to cause the compass needle to turn.
Up next I will tell you guys about Faraday´s Laws of Electromagnetic Induction. Faraday´s First Law on electromagnetic induction states that any changes in the magnetic field of a coil of wire will cause an electromotive force to be induced in the coil. This force is called induced emf and if the conductor circuit is closed, the current will also circulate through the circuit and this current is called induced current. Faraday´s Second Law on electromagnetic induction states that the magnitude of emf induced in the coil is equal to the rate of flux change that links with the coil. The flux linkage of the coil is the product of the number of turns in the coil and the flux associated with the coil.
Last but not least, we have Lenz´s Law on electromagnetic induction. This law states that the direction of the current induced in a conductor by a changing magnetic field is such that the magnetic field created by the induced current opposes the initial changing magnetic field that produced it.
An induction motor is composed of many parts as you can see but we will focus on the ones that are most important, that would be the stator and the rotor.
The stator the stationary part of the motor is kept inside the frame. It is made of ferromagnetic sheets which have gaps on them. These gaps would be where a set of 3 coils stays. All the sets are then connected to each other by an AC current. Each set is called a phase which makes the induction motor of a Tesla a 3-phase induction motor. Every phase has a 120º rotation angle from each other. As proven by Oersted experiment in 1820 an electric current creates a surrounding magnetic field the same argument applies on the stator, so a magnetic field will be created surrounding each phase. Now, remember that I said that in AC current the polarity was changed periodically, the same applies on an AC magnetic field. As you can see by this gif the polarity of one phase is changed each time the wave hits its maximum or minimum .This time we have the 3 phases, here are them on graph just to give you a visual idea of what is happening. Each colour corresponds to a phase which reach their peaks at different times. For the sake of time I will not explain why this happens but if you want, I can explain it after the presentation. So just think that every positive peak on the graph corresponds to a magnetic pole. This will make as you can see a rotating magnetic field or RMF. This is a rotor; it is the physical rotating part of the motor being connected to the motor axis. This one specifically is called a squirrel cage rotor and its name comes from its appearance. The bars of the “cage” are made of copper or aluminium and filling them we have iron laminated sheets. As seen previously the rotor is inside the stator which means that the rotor will be affected by the rotating magnetic field created by the stator. According to the Faradays law any change in the magnetic environment of a closed circuit will create an induced voltage. This is what happens on the conductive bars of the rotor as they are inside of the rotating magnetic field. An electric current flowing on the conductive bars is created, and according to the Lenz’s law the electric current will flow on the opposite direction of the rotating magnetic field. AS the law states: an induced electric current flows in a direction such that the current opposes the change that induced it. If we have an electric current flowing on a closed circuit the Oersted law will be applied again creating a magnetic field on the rotor that has a reverse polarity to the stator. Since the magnetic fields will have opposite polarities the rotor will try to catch up with the rotating magnetic field of the stator, however this will be virtual impossible making this an asynchronous motor. On an asynchronous motor the rotor speed will always lag behind the RMF this difference is called slip. Since the rotor speed is directly proportional to the RMF speed if the frequency of the AC current increases the overall speed of the motor would increase as well. You can see this by looking at the formula used to calculate the speed on an induction motor, bear in mind that this formula would give you the RMF speed for the actual speed of the motor you would then need to subtract for the slip.
The motor gets its energy by the lithium ion battery but like all batteries it stores DC power and motor uses AC. So, in order to the battery to supply the motor it is used an inverter. Normally an inverter just transform DC current do AC but on electric cars the inverter is also connected to the motor controller. Together they act as the brain of the car since is with the motor controller that we can control the frequency of the AC current that reaches the stator which lead to increasing or decreasing the speed of the motor.
Induction motors are overall very efficient but no machine can be 100% efficient without breaking the laws of physics, as Pedro explained in his presentation, and adding up to that, induction motors on cars are limited in their energy input. So, engineers had to think in a way to make the motor more efficient. The solution for this is when the car is not accelerating the kinetic energy that would be lost is converted to energy by transforming the induction motor on an induction generator. On an induction generator the rules are basically the same but now the RMF speed would actually be lower than the rotor speed. The energy is then converted to DC and stored on the battery this all process is called regenerative breaking.
Being simple, reliable and cost-efficient, inductions motors are used on various other applications being even found on households’ appliances. Induction motors have a big impact on industries with about 70 to 80% of all industries energy being transformed into movement by induction motors. Apart from this, induction motors as a whole, are maintenance free and very durable, which lead to their wide use, since their invention to the modern times.
Well, that´s all we got for you until now, I would like to once again remind you that this is a project that will probably extend itself until the 3rd term, or at least we hope it does. To give you something to look forward to in the next term, we have something in mind to show you what we talked about in this presentation working live right before your eyes.
Thank you for having us.
Our theme is Environmental Issues. We chose this theme because it matches our Physics project on one of the topics we will approach sooner or later which is the renewable energy sources theme. So, to start off the presentation, we think we should start by explaining what Environmental Issues are. Environmental issues are every damage to earth and its systems done by humans. This way the list of environmental issues gets huge, therefore we will only cover the most important ones.
Air pollution
Air pollution is a mixture of solid particles and gases that are detrimental to human health and the planet. We compiled a list of the main causes of air pollution in general:
1. The Burning of Fossil Fuels
Sulphur dioxide emitted from the combustion of fossil fuels like coal, petroleum and other factory combustibles is one of the major causes of air pollution. Billions of vehicles that run on roads are powered by gasoline and diesel engines that burn petroleum for releasing energy. Petroleum is made of hydrocarbons, and engines don’t burn them cleanly. As a result, lots of pollutants are emitted from vehicles and airplanes, causing a high level of pollution.
2. Agricultural Activities
Ammonia is a very common by-product of agriculture-related activities and is one of the most hazardous gases in the atmosphere. The use of insecticides, pesticides, and fertilizers in agricultural activities has grown quite a lot. They emit harmful chemicals into the air and can also cause water pollution.
3. Waste in Landfills
Landfills are land areas in which waste is deposited or buried. These deposited or buried wastes generate methane, which is a major greenhouse gas that is highly flammable and very hazardous
4. Exhaust from Factories and Industries
Manufacturing industries release a large amount of chemicals and organic compounds into the air, thereby depleting the quality of air. Petroleum refineries also release hydrocarbons and various other chemicals that pollute the air and also cause land pollution.
5. Mining Operations
Mining is a process where minerals below the earth are extracted using large equipment. During these process, dust and chemicals are released into the air causing massive air pollution. This is the main reason for the deteriorating health conditions of miners and residents nearby the worksites
6. Indoor Air Pollution
Household cleaning products emit toxic chemicals in the air and cause air pollution. Suspended particulate matter, popular by its acronym SPM, is another cause of pollution. Referring to the particles afloat in the air, this is usually caused by dust, combustion, etc. Around seven million premature deaths are caused every year due to the combined effects of ambient (outdoor) and household air pollution cause, according to the World Health Organization.
Now, considering these, which countries pollute the most? We did some research and according to this graphic taken from The Union of Concerned Scientists (figure 1 and 2), we can confirm that China generates the most pollution and is the major contributor to the increase of CO2 levels with 28% of the world’s CO2 emissions (or 10.06 GT). Up next we have the United States with 15% (or 5.41GT) and India with 7% (or 2.65GT), which will be the countries we will be focusing on in this project, for being the biggest air polluters
In terms of China here are the main causes of the air pollution:(Figure 3),
· An enormous economic boom, since with this amplified wealth, it is easier to afford a motor vehicle. Currently in Beijing, there are 3.3 million vehicles with nearly 1200 bought every day, emitting 70% of the city's air pollution. These vehicles emit toxic gases such as sulphur dioxide, nitrogen dioxide, carbon monoxide.
· Population growth: it contributes to extensive pollution, and has increased from 1.34 billion to 1.39 billion in just 7 years
· Output from manufacturing: this output mainly comes from coal burning factories, which rely on old-fashioned and ineffective technologies. Air quality worsens in spring and summer when temperature and humidity levels rise, and winds contribute to the smog by carrying pollutants from other industrialized regions.
The United States contribute to the increase of CO2 and greenhouse gases in several ways (Figure 4):
· Transportation: Greenhouse gas emissions from transportation primarily come from burning fossil fuel for vehicle usage.
· Electricity: Electricity production generates the second largest share of greenhouse gas emissions. Approximately 63 percent of America's electricity comes from burning fossil fuels, mostly coal and natural gas.
· Industry: Greenhouse gas emissions from industry primarily come from burning fossil fuels for energy, as well as from certain chemical reactions necessary to produce goods from raw materials.
· Commercial and residential sectors: Greenhouse gas emissions from businesses and homes arise primarily from fossil fuels burned for heat, the use of certain products that contain greenhouse gases, and the handling of waste.
· Agriculture: Greenhouse gas emissions from agriculture come from livestock such as cows, agricultural soils, and rice production.
India contributes to the increase of CO2 and greenhouse ways in several ways(Figure 5):
· Fuel and biomass burning: Fuel wood and biomass burning is the primary reason for near-permanent haze and smoke observed above both rural and urban India. India is the world's largest consumer of fuelwood, agricultural waste and biomass for energy purposes. From the most recent available nationwide study, India used 148.7 million tonnes of coal replacement worth of fuelwood and biomass annually for domestic energy use
· Fuel adulteration: Some Indian taxis and auto-rickshaws run on adulterated fuel blends. Adulteration of gasoline and diesel with lower-priced fuels is common in India. Some adulterants increase emissions of harmful pollutants from vehicles, worsening urban air pollution.
· Traffic congestion: Traffic congestion is severe in India's cities and towns. It reduces the average traffic speed. At low speeds, scientific studies reveal that vehicles burn fuel inefficiently and pollute more per trip. The average trip speed on many Indian city roads is less than 20 kilometres per hour. At such speeds, vehicles in India emit air pollutants 4 to 8 times more than they would with less traffic congestion.
· Greenhouse gas emissions: About 65 percent of India's carbon dioxide emissions in 2009 were from heating, domestic uses, and powering sector and about 9 percent of India's emissions were from transportation.
Top 3 afetados (ar): Bangladesh, Pakistan, Mongolia (Figure 6)
Air Pollution Consequences
Both short-term and long-term exposure to high levels of air pollution increase the risk of respiratory infections, heart diseases and lung cancer. Older and already ill people are hit with more impact. The most health-harmful pollutants are a specific type of airborne particles called PM2.5.
PM (or particulate matter) is the term for particles found in the air, including dust, dirt, smoke, and liquid droplets. Large concentrations of particulate matter are usually emitted by sources such as diesel vehicles and coal-fired power plants. These PM2.5 particles are referred to as "fine" particles because of their small size (approximately 1/30th of the average width of a human hair), being able to penetrate deep into the lung passageways.
Air pollution also has a major impact on the process of plant evolution by preventing photosynthesis and, in many cases, with serious consequences on the purification of the air we breathe.
The accumulation of gases in the atmosphere also generates environmental problems with already known consequences such as acid rains, the depletion of the ozone layer, global warming, the greenhouse effect, etc. The concentration of these gases in the atmosphere increases on average by 1% per year. This phenomenon is due to the properties of certain gases like carbon dioxide, methane and nitrous oxide, being carbon dioxide the most abundant in the atmosphere with a share of 81% of all greenhouse gas emissions according to a study developed in 2018 by the US EPA (United States Environmental Protection Agency), to trap heat from the sun in the atmosphere, preventing it from returning to space after being reflected by Earth and therefore heating earth´s atmosphere even more.
Air pollution contributes to the formation of acid rains which are created after the release of toxic gases due to the combustion of fossil fuels. When these gases enter in contact with water vapor and oxygen in the atmosphere the pH of the water gets lower. Acid rains affect the acidity in soils and freshwater, affecting food chains.
Solutions
The solutions suggested by WHO are:
- Developing sustainable transport in cities; (So developing public transport in a way that is more accessible and efficient. Consequently, this will make less people go to work by car and opt for public transport. This also means migrating transportation from fossil-based energy to other alternatives such as renewable energy.)
- Implementing solid waste management; (For example using thermal treatments such as incineration. This method consists in the combustion of waste and in the recovery of energy.)
- Providing access to clean household fuels and cookstoves;
- Developing market for renewables energies and energy efficiency; (This will make not only a better development in the already existent renewable energies but will allow progress in new ones.)
- Implementing industrial emissions reductions; (This includes a better energy efficiency, fuel switching, use of renewable energy, and the more efficient use and recycling of materials.)
Water Pollution
Water pollution is when a lake, river, ocean, stream, aquifer, or any body of water is contaminated by harmful substances, degrading the quality of the water. (Small presentation)
Causes
1. Industrial Waste
Industries produce a huge amount of waste, which contains toxic chemicals and pollutants, causing air pollution and damage to the environment and ourselves. They contain harmful chemicals, including lead, mercury, sulphur, nitrates, and many others, which are released into canals, rivers and later into the sea. These may change the colour of water and cause what it’s called eutrophication (the bloom of algae in the water and the depletion of oxygen in the water), may change the temperature and be a massive hazard to water organisms2. Sewage and Wastewater
The sewage and wastewater that is produced in each household are treated chemically and released into the sea along with fresh water. The sewage water carries harmful microorganisms and chemicals which are known to cause some very deadly diseases. When carrying the sewage, if a small leakage from the sewer lines happens, it can contaminate the underground water and make it the water not safe to drink. Also, if not repaired on time, the leaking water can rise to the surface and can become another breeding ground for creatures that can act as carriers of diseases.
3. Mining Activities
Mining is the process of crushing the rock and extracting coal and other minerals from the underground. These elements, when extracted, contain harmful chemicals and elements, such as metal waste and sulphides, and can increase the number of toxic elements when mixed up with water, which may result in health problems.
4. Marine Dumping
The garbage produced by households in the form of paper, food, aluminium, rubber, glass, and especially plastic sometimes is collected and dumped into the sea. These items can take 2 weeks to 200 years to decompose. When such things enter the sea, they not only cause water pollution but also harm animals in the sea.
5. Accidental Oil Leakage
Oil spill causes a huge threat to marine life when a large amount of oil spills into the sea as it does not dissolve in water. It affects local marine wildlife, including fish and birds. Such an oil spill can cause a lot of damage to species , depending on the amount of oil that reached the water, the toxicity of pollutants, and the size of the area affected.
6. Fossil fuels
Fossil fuels like coal and oil, when burnt, produce a substantial amount of dangerous acidic particles in the atmosphere. When these mix with water vapor, it results in acid rain. Accidental leakage may happen anytime and may cause damage to the environment and result in soil erosion.
7. Chemical fertilizers and pesticides
Chemical fertilizers and pesticides are utilized by farmers to protect crops from insects and bacteria, which contribute to the plant’s growth. However, when these chemicals are mixed up with water, they produce harmful pollutants for plants and land animals. If the chemicals mix with rainwater and flow down into rivers and canals, it can pose serious damages for marine species
8. Global Warming
A rise in the earth’s temperature results in global warming due to the greenhouse effect. It increases the water temperature and results in the death of marine species, which later results in water pollution.
9. Radioactive Waste
The nuclear waste that is produced by radioactive material needs to be disposed of to prevent any nuclear accident. Nuclear waste can have serious environmental hazards to the sea if not disposed of properly.
10. Urban Development
As the population has grown exponentially, so has the demand for housing, food, and cloth. As more cities are developed, they have resulted in increasing use of fertilizers to produce more food, soil erosion due to deforestation, inadequate sewer collection and treatment, landfills as more garbage is produced and increase in chemicals from industries to produce more materials.
11. Animal Waste
The waste produced by animals goes away into the rivers when it rains. It then gets mixed up with other harmful chemicals and causes various diseases like diarrhea.
Now, considering these, which countries pollute the most? We did some research and according to this graphic taken from Condor Ferries, we can confirm that China is the biggest contributor to water pollution with 8.80 million metric tons of mismanaged plastic entering the sea, followed by Indonesia, with 3.20 million metric tons and the Philippines, with 1.9 million metric tons. Keep in mind, we are only talking about plastic, but plastic is a major contributor to water pollution all around the world. (Figure 7)
Meanwhile, if we look at this table from the Ocean Health Index, we can see that the most affected countries are Nicaragua with an Overall Index Score of 44, followed by Sierra Leone, with a score of 46 and Lebanon with a score of 47. (Figure 8)
Consequences
Consequences on Human Health
Water pollution can make people ill and, in more severe cases, kill. Contaminated waters caused 1.8 million deaths in 2015, according to a study published in The Lancet. Every year, unsafe water sickens about 1 billion people and some low-income communities are unfortunately at risk because their homes are too close to the most polluting industries.
Waterborne pathogens from human and animal waste are a major cause of illness from contaminated drinking water. Even in wealthy nations, accidental releases from sewage treatment facilities, contribute harmful pathogens to waterways. For example, thousands of people across the United States get sick every year with the Legionnaires’ disease (a severe form of pneumonia contracted from water sources)..
Consequences on the Environment
When water pollution causes an algal bloom in a marine environment, the sudden appearance of newly introduced nutrients stimulates plant and algae growth, which then reduces oxygen levels in the water. This reduction of oxygen, known as eutrophication, suffocates plants and animals and can create “dead zones”, where waters are essentially devoid of life.
Chemicals and heavy metals from industrial and municipal wastewater contaminate waterways as well, and these are toxic to aquatic life—usually reducing an organism’s life span and ability to reproduce—and make their way up the food chain as predator eats prey. That is how tuna and other big fish accumulate high quantities of toxins, such as mercury.
Marine ecosystems are also threatened by marine debris, which, as you might already know, can strangle, suffocate, and starve animals. Much of this solid debris, such as plastic bags and soda cans turn our oceans into some sort of trash soup and sometimes consolidating to form floating garbage patches.
Solutions
Improvements in wastewater treatment (This is one of the best ways to reduce water pollution as wastewater treatment plants are very effective. When sewage water enters a wastewater treatment plant it goes through several chambers where it is submitted to physical, chemical, and biological processes to make sure that all the pollutants are removed);
Reduce plastic consumption(If big companies don’t stop producing huge amounts of plastic it is up to the consumers to stop buying their products and opt for more ecological approaches)
Oil Spill Prevention;(The best solution for oil spills is their prevention. This involves the better training of the teams, staying on the prescribed path for the journey and in following a very strict plan while bringing the ships to the port. However in the case of an oil spill the most popular approach is to contain the crude in a small area to prevent it from spreading, this method is called oil boom.)
Green Agriculture;(One of the methods used on green agriculture is the embrace of farming practices that mimic natural processes. One of the ways that green agriculture helps to reduce water pollution is in the usage of greener pest control options instead of the more conventional ones. One example is ladybugs that can be used for aphid control as they are their natural predator.)
Climate change
Climate change is a global phenomenon described by the shifting of the usual climate of the planet that is mostly caused by human activities, such as temperature, rain and wind changes. As a result of unbalancing the weather of Earth, the sustainability of the planet’s ecosystems is in danger, as well as the future of humankind and the stability of the global economy.
This can be caused by various events, but scientists believe that the factor that is most contributing to climate change is the “greenhouse effect”.
The greenhouse effect is when gases in the atmosphere block heat from escaping. Gases that do not respond physically or chemically to changes in temperature are described as "forcing" climate change. Gases which can respond physically or chemically to changes in temperature are called "feedbacks."
Gases that contribute to the greenhouse effect include:
Water vapour: The most common greenhouse gas and acts as a feedback to the climate. Water vapour increases as the Earth gets hotter, but also increases when there is the possibility of clouds and rain, making these important feedback processes to the greenhouse effect.
Carbon dioxide (CO2): A minor but very important component of the atmosphere, since this is the most important gas “forcing” climate change, carbon dioxide is released through human activities such as deforestation, land use changes, and burning fossil fuels. Since the Industrial Revolution, Humans have raised CO2 levels in the atmosphere by 47%.
Methane: A hydrocarbon gas produced through human activities, including the decomposition of wastes in landfills, agriculture, and especially rice cultivation, as well as ruminant digestion and manure management associated with domestic livestock. Despite methane being more active in the atmosphere than carbon dioxide, it’s much less abundant.
Nitrous oxide. A greenhouse gas produced by soil cultivation, the combustion of fossil fuels and biomass burning, and, especially by the use of commercial and organic fertilizers.
Chlorofluorocarbons (CFCs). Synthetic compounds of industrial origin that are used in some applications but are now largely regulated in the production and release to the atmosphere for their ability of destruction of the ozone layer.
Consequences of Climate Change
Climate change is most likely the greatest cause of species’ extinctions this century. The IPCC (Intergovernmental Panel on Climate Change) says a 1.5°C rise may put 20-30% of all species in risk of extinction. If the planet warms by more than 2°C, most ecosystems will struggle. Many of the world’s threatened species live in areas that will be severely affected by climate change and, unfortunately, this is happening too quickly for these species to adapt to the changes.
The Impact of Climate Change in the Polar Regions
Climate change has a bigger impact in the Polar Regions. The earth’s north and south extremities are crucial for regulating our planet’s climate and are particularly vulnerable to the impacts of global warming, which has global and very serious consequences.
The Antarctic ice sheet is the largest mass of ice on earth, spanning for almost 14 million sq km. This ice plays a very important role in influencing the world’s climate, reflecting back the sun’s energy and helping to regulate global temperatures. Even slow melting is likely to have significant effects on the global sea level rise.
The Impact of Climate Change in the Oceans
Oceans are sometimes described as ‘carbon sinks’, meaning that they absorb an enormous amount of carbon dioxide, preventing it from reaching the upper atmosphere. Water temperatures and concentrations of carbon dioxide are becoming higher and higher each day, which makes the oceans’ waters become more acidic, provoking a huge impact on our oceans.
Oceans are already experiencing large-scale changes in temperature, with critical thresholds expected to be reached at 1.5°C and above. At this temperature, coral reefs are expected to diminish by a further 70-90% and, at a warming of 2°C, all coral reefs will be lost.
The Impact of Climate Change in the Forests
Just like the oceans, forests are vitally important as they soak up carbon dioxide, the main greenhouse gas responsible for global warming, and help regulate the world’s climate. They’re also home to countless plant and animal species and this is one of the many reasons why there are currently many organizations working to protect our forests. Impacts vary in the different kinds of forests. In tropical forests such as the Amazon, where there's abundant biodiversity, even moderate levels of climate change can cause high levels of extinction. Also, due to wildfires, when large areas of forest are destroyed it’s disastrous for the local species and communities that rely on them. Dying trees will release their stores of carbon dioxide, adding them to atmospheric greenhouse gases and worsening our current situation.
Solutions
Climate change is basically caused by the greenhouse effect as said earlier and therefore the solutions for climate change would be the prevention of the greenhouse effect. To stop climate change it would take a planetary effort as we would have to stop air and water pollution, change to renewable energies, improve our waste management and actively use the 3 r’s circular economy. Thankfully we can see more and more countries adopting new policies to help in the prevention of climate change and we hope that in the next term you all can be here to hear us talk about the political side of the environmental issues.