The 4 Spheres
The four interdependent spheres make up all of the living and non-living components of our Earth. The Earth can be broken into four subsystems, known as spheres, namely the geosphere, also called the lithosphere or ‘all the land on Earth,’ the hydrosphere or ‘all the water on Earth,’ the biosphere or ‘all the living things on Earth,’ and the atmosphere or ‘all the gasses that surround the Earth.’
Geosphere
“Geo” means Earth. The geosphere, also referred to as the lithosphere contains all the rocks and minerals from the ground to the Earth’s core. It is the solid outer part of the Earth that includes the core, the mantle and the crust. It is the Earth’s outermost layer below the atmosphere. Its surface is uneven, ranging from high mountain ranges to flat plains and deep valleys. The outer layer consists of soil rich in nutrients, oxygen and silicon layered with a semi solid mantle rich in oxygen, silicon, iron and magnesium and which below lies a liquid core made of nickel and iron coupled with a solid core at the center of the Earth. 1
Hydrosphere
“Hydro” means water. This sphere ranges from 10- 20 kilometers in thickness and contains all of the solid, liquid and gaseous water on Earth such as oceans, rivers, lakes, groundwater and water frozen in glaciers. It extends about 12 kilometers into the atmosphere from the surface of the Earth and then down into the lithosphere. Only a portion of this water is fresh that flows from precipitation in the atmosphere to the surface of the Earth as groundwater, rivers and streams. Most the fresh water is stored frozen. Ninety-seven percent of the Earth’s water is found in the oceans. Water is essential for life and makes up for about 90 % of living things.2
Atmosphere
“Atmos” means air. This sphere contains all the gasses surrounding the Earth. It extends from less than one meter below the Earth’s surface to more than ten thousand kilometers above the surface. The gases in the atmosphere help support life on Earth. The upper portion protects the living things on the biosphere from ultraviolet radiation from the sun and absorbs and emits heat. This is where weather occurs.
Biosphere
“Bio” means life. The biosphere contains all of the living things on Earth including people, animals, plants, insects and micro-organisms. In this sphere living things interact with all the other spheres. They need water from the hydrosphere, chemicals from the atmosphere and nutrients gained from the biosphere. It is here that the living things create ecological communities otherwise known as biomes, dependent upon their physical surroundings. They have common characteristics based on the environment they exist in. The seven major biomes include deserts, grasslands, tundra, taiga, tropical rainforest, savanna and temperate forest.
How the Four Spheres Interact
The four spheres drive the processes on Earth and support life. Although each are previously described in terms of its features and all have their own identities, they all interact. The spheres are connected such that a change in one, often results in a change in another. This is because the various materials on Earth often change form or cycle amongst the spheres. They can get recycled into other phases. For example, when a plant dies, it settles into the ground and then becomes broken down by microorganisms which later becomes soil to feed new plants. The water cycle also goes through different phases as well as locations such that it evaporates from the oceans, rains down into lakes or onto the ground. Even rock is recycled under the Earth’s surface which then resurfaces as a volcanic eruption resulting in chemical weathering.
Just like these examples, almost every process or event on Earth involves more than sphere. Ocean currents in the hydrosphere affects air temperature in the atmosphere by moving heat from the equator to the poles. Another example is when erosion happens on land by wind or water from the atmosphere or hydrosphere or both, which then shapes the land geosphere. Such events that either occur naturally like a hurricane, or are caused by humans, such as pollution effects two or more spheres. These events can either cause changes or be the effect of a change in the spheres. This cause-and-effect relationship is referred to as an interaction. Interactions can cause changes both locally and worldwide. Understanding these interactions helps people understand and prepare for its effects. Understanding the interactions within and between the spheres will later help students understand the how the cycles and relationships within an ecosystem interrelate.3
Ecosystems
Now that we have an understanding of the four spheres, let’s look at life within the spheres and how its supported. “An ecosystem is the interacting system made up of all the living and nonliving objects in a specified volume of space.” 4 They form a delicate balance to help sustain each other and interact with the non-living elements, such as climate, soil and water. An ecosystem can range from a small pond to a vast ocean. A change, addition or alteration of an ecosystem can disrupt the balance, much like the effects that ripple through the interdependent spheres.
This balance often can fluctuate between the interactions among the populations or community within a habitat. A population is a group of individuals of the same species. A community is all the organisms or populations in a habitat. A habitat is where something lives and a community is what lives there. A community consists of all the organisms that live in a particular area rather than a single species, including microbes, fungi, animals and plants.
Every ecosystem is composed of both abiotic and biotic components that interact in order to keep the balance. Abiotic refers to all of the non-living chemical and physical features such as air, temperature, weather, climate, water, soil and minerals. They vary from region to region and are important to supporting life. Within an ecosystem there are limiting factors that can determine or restrict population growth and diversity of biotic factors in an ecosystem. Biotic refers to all the living organisms in the environment that compete for resources. They have a direct or indirect influence on other organisms in. the environment such as plants, animals and their waste material. An ecosystem is self-sufficient and cyclical in which nutrients are transported around and within the ecosystem. One example is organic carbon. Organic carbon transfers energy from organism to organism through digestion and then is added back to the atmosphere as carbon dioxide. Later, the carbon dioxide is taken from the atmosphere by photosynthesis and converted back to organic carbon and the cycle continues. Various nutrient cycles apply to every ecosystem. First, we will take a look at two types of ecosystems, followed by the cycles that exist in each.
Types of Ecosystems
Ecosystems are often categorized as either terrestrial or aquatic. They are categorized in accordance to their characteristics. Terrestrial ecosystems are land based and include forests and grasslands. Forests usually get more rain than grasslands and are home to a variety of animals depending on the type, deciduous or rainforest. Black bear, deer, red fox and rabbit are found in a deciduous forest while panther, monkeys, snakes and spiders are found in the rainforest. Temperatures vary in accordance with location. Grasslands consist mostly of fertile soil and tall grasses. Grasslands are home to prairie dogs, bison and grasshoppers.
Aquatic ecosystems are water based and can consist of fresh water lakes and ponds, rivers or saltwater oceans, estuaries or marshes. Lakes and ponds are bodies of freshwater surrounded by land and are usually shallower with an even water temperature throughout. Plants and algae often occupy much of the edges. It is home to fish, amphibians, ducks, turtles and beavers. Oceans on the other hand are large bodies of saltwater that are divided by continents. The conditions, sunlight, temperature, depth and salinity of the ocean will determine what types of ecosystems thrive there. Many organisms live in the shallower areas because the sunlight can warm the water, making food abundant. Organisms that live here include jellyfish and seaweed, fish and crabs. Other organisms live in the open ocean, the surface or deep within, such as coal, plankton, fish, octopus, whales and sharks. 5
Energy and Nutrients in an Ecosystem
Neither terrestrial nor aquatic ecosystems could not exist without the energy to support it. Energy is often defined as the ability to do work. There are various forms of energy such as thermal, radiant, chemical, nuclear, electrical, motion, sound, elastic and gravitational. These forms are categorized by energy potential which is stored energy, energy of position and kinetic energy or energy in motion in waves, electrons, atoms, molecules, substances and objects. Energy can neither be created nor destroyed, it must be transferred or changed from one form into another. The primary source of energy in the majority of these ecosystems is energy from the Sun. Light energy that powers most ecosystems enters through plants because of their ability to capture visible light and transform it to a usable chemical form (sugar) via photosynthesis. Although this is the most widely used energy source in an ecosystem, other examples include fossil fuels, geothermal energy, wind and water. Energy flows consistently in and out of an ecosystem like a cycle. Energy in an ecosystem flows from the Sun to plants and algae and ultimately to animals, bacteria and other organisms that consume them. This energy is transferred via a food web.
Food Chain and Food Webs
Just as the four spheres are interconnected and a change in one sphere can create a change in another, food webs have a similar reaction through energy transformation and transfers. Food chains represent the transfer of energy and nutrients through a succession of organisms in a repeated process of eating and being eaten. As the energy is transferred each organism plays a role. Plants, algae and bacteria are known as producers because they can produce their own food, while the consumers or other organisms that eat or decompose living things are consumers. The amount of energy that is transferred from producer to consumer and consumer to consumer varies in accordance with their food chain. Food chains follow one path of energy and materials transferred while a food web follows many interconnected links of food chains in a complex system.
In a food chain producers and consumers in an ecosystem are arranged into a “feeding group,” known as a trophic level. Energy flows through each level, but not all of the energy generated or consumed in one level is available to the next. In each transfer, energy is lost to processes like respiration. Only about 10% of the available energy is on average transferred to the next trophic level. A large amount of energy is lost into the atmosphere as carbon dioxide. When energy is transferred from one trophic level to another, it is organic carbon moving up the food chain. When organic carbon is decomposed to carbon dioxide to get energy to maintain the function of an organism, the carbon goes into the atmosphere as carbon dioxide and is lost. Because of this there are often three-five trophic levels in an ecosystem since there is not enough energy to support more than that. With less energy at the higher trophic levels, there are generally fewer organisms. The organisms tend to be larger in size, but fewer in number.
All food chains and webs have at least two or three trophic levels. Each of the trophic levels differs in its nutritional relationship with the primary energy source, the Sun. Solar radiation from the Sun if first used by the primary producers or autotrophs such as plants and algae who manufacture their own food source through photosynthesis in the first level. Levels two through five are made up of consumers or heterotrophs who do not produce their own food but instead consume plants directly, other organisms, or dead organic matter in order to acquire nutrition. They also use this energy for themselves to maintain functions, such as respiration. The second level, known as the primary consumers, consists mostly of herbivores (plant eating), gaining their energy from primary producers either directly or through their detritus. Levels three through five consist of carnivores (meat eating) and omnivores (plant and meat eating). Carnivores and omnivores that eat herbivores, called secondary consumers make up the higher trophic levels. The secondary consumers are then consumed in level four and identified as tertiary consumers. Levels four and higher often consist of animals known as apex predators, who have no natural predators.
The decomposers, such as fungi, bacteria, earthworms and flies do not have an independent trophic level, but recycle waste from all the other levels consume the dead plant and animal material, convert it into energy and nutrients to help plants grow. 6
Cycles in an Ecosystem
Interactions within the ecosystem amongst the trophic levels keep the ecosystem in balance. Just as this balance is necessary to support life, so must the cycles that sustain it remain in balance. The growth of the organisms within each ecosystem depends upon the elements and compounds that are most essential and have their own interlinking cycles. The three main cycles in an ecosystem are the water cycle, the carbon cycle and the nitrogen cycle. Together, these cycles are responsible for removing waste materials and then replenish the ecosystem with nutrients to sustain life.
The Water Cycle
There would be no life on Earth without water, as all living things need water to survive. The water cycle is the repeated movement of water between the atmosphere and the Earth’s surface. Earth’s water is recycled through the processes of evaporation, condensation, transpiration and precipitation. The water cycle describes how water evaporates from the Earth’s surface, rises into the atmosphere where it will cool and condense into rain or snow in clouds then later fall again as precipitation. It is a constant global process circulating water from clouds to land and the ocean, and then back to the clouds.
Precipitation is when water falls to the Earth from the atmosphere in the form of rain or snow. As water droplets in a cloud are enlarged, they become too heavy to remain in the air and gravity pulls the water to Earth. It is a vital component to how water moves because it connects the ocean, land and atmosphere. Most water in the air is from evaporation off the oceans. Evaporation is the changing of a liquid into a gas. As bodies of water like oceans and lakes absorb heat energy from the Sun, the liquid water is changed into a gas called water vapor. While some of the precipitated water is absorbed into soil and used by plants, the plants lose this water through their leaves in transpiration. This water is then released by the plant as water vapor through their stomates. Water used by animals during cellular respiration is also released into the air as water vapor when they breathe, sweat or excrete. Condensation is the changing of a gas into a liquid. As the air rises, it cools, the water vapor loses heat, condenses and changes back into a liquid. The water vapor that changed into droplets of water form clouds. This cycling is linked with the exchange of energy between the atmosphere, ocean and land that determines the Earth’s climate. Impacts of climate change occurs primarily through water cycle changes.7
The Nitrogen Cycle
Another primary nutrient critical for the survival of living organisms is nitrogen. It is one of the elements organisms need to make proteins. It is also one of the main elements needed by Rubisco, the enzyme that facilitates primary production. Although abundant in the atmosphere, about 78 percent, as dinitrogen gas, it is mostly inaccessible in this form to most organisms making it a scarce resource which then can limit primary productivity in an ecosystem. Nitrogen needs to be combined with other elements in order that organisms can use it. Nitrogen, therefore undergoes different transformations in an ecosystem changing forms as it is used. The process of combining nitrogen from the atmosphere with other elements is known as nitrogen fixation. This process makes dinitrogen gas accessible to organisms. Here the nitrogen is transformed into usable nitrogen by nitrogen-fixing bacteria that live in water, soil, or the roots of legume plants. This bacteria changes nitrogen into ammonia, while other bacteria will change ammonia into nitrates. Once the nitrogen has undergone these transformations it can be used by plants and animals. Plants get their nitrogen from the soil, while animals get it from eating the plants or other animals that have eaten the plants. Decomposers break down dead organisms and wastes into ammonia which can also be turned into nitrates in the soil by nitrifying bacteria. Still other bacteria, called denitrifies, will break down the nitrates and release nitrogen gas and returned into the air continuing the cycle of using and reusing nitrogen in an ecosystem.8
Carbon Cycle
Carbon is the foundation of life on Earth. It helps regulate the Earth’s temperature, is a key ingredient in the food we eat and is an energy source that fuels the economy. Carbon is the backbone of all organic compounds found in nature. It is also found in inorganic forms such as carbon dioxide. Carbon is found in a variety of forms and can enter the atmosphere in many ways. The most common way for carbon to be removed from the atmosphere is through plants by photosynthesis, where by the carbon dioxide is converted to sugar. Just as carbon exists in terrestrial ecosystems, it can also enter aquatic ecosystems by becoming soluble in water and forming compounds like carbonic acid or by being used by organisms to form shells of calcium carbonate. Additionally, it is found as ions known as bicarbonates from weathered rocks. Carbon generally gets back to the form of carbon dioxide from the process of respiration by living thing things, reentering the atmosphere or aquatic ecosystems. The process by which carbon moves into and out of different spheres is known as the carbon cycle.9
The carbon cycle follows a series of steps. First, carbon moves from the atmosphere to plants. In the atmosphere, carbon is attached to oxygen in a gas called carbon dioxide (CO2). Through the process of photosynthesis, carbon dioxide is pulled from the air to produce food made from carbon for plant growth. Then carbon moves from plants to animals and bacteria. Through food chains, the carbon that is in plants moves to the animals that eat them. Animals that eat other animals get the carbon from their food too. Next, carbon moves from plants and animals to soils. When plants and animals die, their bodies, wood and leaves decays bringing the carbon into the ground. Some is buried and will become fossil fuels in millions and millions of years. Carbon then moves from living things to the atmosphere. Each time you exhale, you are releasing carbon dioxide gas (CO2) into the atmosphere. Animals and plants need to get rid of carbon dioxide gas through a process called respiration. From here, carbon moves from fossil fuels to the atmosphere when fuels are burned. When humans burn fossil fuels to power factories, power plants, cars and trucks, most of the carbon quickly enters the atmosphere as carbon dioxide gas. Each year, nine billion tons of carbon is released by burning fossil fuels. Of this massive amount, nearly five billion tons stays in the atmosphere. Most of the remainder becomes dissolved in seawater or stored in terrestrial ecosystems in a carbon sink. Carbon then moves from the atmosphere to the oceans. The oceans, and other bodies of water, absorb some carbon from the atmosphere. The carbon is dissolved into the water.11
Figure 1: Pre-Anthropogenic Carbon Balance10
Sink Versus Source
Because Carbon is constantly moving between stores like the forests, soil, oceans, atmosphere and fossil fuels, the stores act as either a sink or a source. Processes that release carbon dioxide into the atmosphere are called “sources”, while processes that absorb it are called “sinks.” A sink absorbs more carbon than it gives, while a source gives off more than it absorbs. The balance between global sinks and sources effects the amount of carbon in the atmosphere at any given time. Natural sources of atmospheric carbon dioxide include volcanoes, fires, decomposition, respiration, digestion and in some cases oceans and bodies of fresh water. Photosynthesis, and reactions of atmospheric carbon dioxide with rock minerals are natural sinks. Over very long time scales the creation of coal and other fossil fuels were carbon sinks.
Sinks and sources work together to create a carbon budget. As we learned, our planet has a natural way of subtracting carbon from the atmosphere, but each year we are adding more than can be subtracted, causing the remaining to build up in the atmosphere, thus forming an atmospheric carbon excess. Because ecosystems vary by type as well as their place in the world the carbon budget varies in relationship to its’ location on Earth.12
The Carbon Budget
The pre-anthropogenic carbon budget is a conceptualization of how the earth’s carbon budget balanced before major human disturbance. Creating this natural carbon budget helps us to understand how the carbon budget changes due to carbon dioxide pollution. While forests and oceans act as natural carbon sinks, it is increasingly difficult to balance the amount based on the rate in which greenhouse gases are getting added to the atmosphere. We want to limit the rise of average global temperatures to less than 2 degrees Celsius, so that the amount of carbon dioxide building up in the atmosphere is limited and won’t compromise our future climate from irreversible effects.
Carbon Pools
In an effort to prevent these effects we must understand that carbon is in a constant state of movement and is stored in a variety of pools. The four most relevant categories connected with the overall carbon cycle are found within the lithosphere, oceans, atmosphere, terrestrial ecosystems.
The largest amount of carbon on Earth is stored in sedimentary rocks that were produced either by the hardening of mud into shale over time or by calcium carbonate particles from shells and marine organism skeletons into limestone. The Earth’s crust also stores a sizeable amount of carbon as hydrocarbons known as fossil fuels, formed millions of years ago from ancient living organisms.
Next, the Earth’s oceans contain a large pool of carbon stored with their great depths in the form of dissolved inorganic carbon. A much smaller amount of carbon is located at the surface of the ocean. The carbon at the surface of the ocean exchanges with the atmosphere through carbon dioxide dissolving into the water and through the growth, death and decay of plankton.
Carbon is also stored in the atmosphere in the form of carbon dioxide along with smaller amounts of methane and various other compounds. The carbon found here is of vital importance due to its influence on global climate. Although the amount is relatively small, the size of the atmospheric carbon pool makes it very sensitive to disruptions and interactions caused by increases in the sources or sinks from other pools.
Carbon is also contained in terrestrial ecosystems in the forms of plants, animals, soils and microorganisms. These forms are all organic, entering in the form of dead plant matter broken down during decay that then releases the carbon back to the atmosphere. There are also very large stores of inorganic carbon in soils in the form of carbonate and silicate minerals. These minerals interact with the carbon dioxide to form bicarbonate which is a carbon sink on land.
Carbon Fluxes
This movement or transfer of carbon from one pool to another is called a flux. It moves through these pools through a variety of processes or fluxes including photosynthesis, plant respiration, litter fall, soil respiration, and ocean -atmosphere exchange. During photosynthesis, as plants combine the energy from the sun and carbon dioxide with water and soil, carbon is removed from the atmosphere and stored within the plants. Depending on the lifespan of the plant, carbon is stored for relatively long periods of time. Plants also release carbon dioxide back into the atmosphere through respiration. Plants are made of carbon, as they shed their leaves, roots and branches, this carbon is transferred into the soil in terrestrial ecosystems. This dead plant material is called litter. Plants aren’t the only organisms that release carbon dioxide through respiration. Dead organic matter is decomposed releasing carbon dioxide into the atmosphere at a rate of sixty gigatons of carbon a year and because it takes years to decompose, it can also be stored in the soil.
Inorganic carbon, absorbed and released within the ocean surface and air, happens through diffusion. After it is dissolved, the carbon dioxide goes through chemical reactions joining water and carbon dioxide to form carbonic acid. Within the ocean there is also a lot of carbonates from the weathering of rocks on land that are delivered to the oceans by rivers. The formation of carbonate causes oceans to store a much larger amount of carbon as well as provides marine animals with this mineral to help form shells. Additionally, aquatic plants break down on a much quicker scale than on land. The total amount of uptake and loss of carbon from an ocean is dependent on the balance between inorganic and organic processes.
This is in addition to fluxes associated with human activities in fossil fuel combustion, and land cover change. The most important flux that stems from human activities is the combustion of fossil fuels, coal, oil and natural gas, because the main byproduct of fossil fuel is carbon dioxide. Land cover change in the form of deforestation is another human activity that causes a flux of carbon to the atmosphere. As population increases, native ecosystems are converted to farms and urban areas. Forests and other native ecosystems generally contain more carbon than that which replace them. This results in a net flux of about 1.5 gigatons of carbon per year.13
Climate Change and The Greenhouse Effect
It’s imperative to understand the budget and the roles we play in it because carbon dioxide is a greenhouse gas contributing to global warming and climate change. Climate is how the atmosphere behaves over a long period of time. It is the long term global or regional average of temperature, humidity, and rainfall patterns. Some may confuse the term climate with weather. Weather, however describes the short-term changes in the atmosphere. Water cycling in and out of the atmosphere significantly impacts weather patterns on Earth. This exchange of energy between the atmosphere, ocean and land determines the climate on Earth. The impacts of climate change occur mainly through changes in the energy, water and carbon cycles. Climate change refers to the rise in average surface temperatures on Earth primarily due to human use of fossil fuels. This releases greenhouse gases into the air that trap heat in the atmosphere causing a range of effects on ecosystems like the rising sea levels, severe weather events, droughts and wildfires. 14
The greenhouse effect is the process that occurs when gasses in the Earth’s atmosphere trap the Suns’ energy or heat, helping to keep it warmer than it would be without an atmosphere. Carbon is one of the greenhouse gasses that traps this heat. Other gases include methane, nitrous oxide and sulfur hexafluoride. Water vapor however is the most important because globally it is the most abundant. The concern however is generally placed upon carbon dioxide, the second most abundant followed by methane, nitrous oxide and sulfur hexafluoride because human impact play a large role in the growing concentrations of these gasses.
Green House Gasses
Carbon Dioxide – a colorless, odorless gas made up of two oxygen atoms and one oxygen atom. It is produced when an organic compound like wood or fossilized organic matter like coal, oil or natural gas is burned in the presence of oxygen. It’s removed from the atmosphere by carbon sinks.
Methane- a colorless, odorless, nontoxic gas that is made up of four hydrogen atoms and one carbon atom. Methane is the main constituent of natural gas and is combustible. It is released when organic matter decomposes in the absence of oxygen. Natural sources include wetlands, swamps, marshes, termites and oceans. Mining fossil fuels and the transportation of natural gas are human sources as well as the digestive processes of cattle and buried waste in landfills. It is broken down in the atmosphere when it reacts with hydroxyl radicals.
Nitrous oxide is a colorless, non-flammable gas with a sweet smell and is often known as ‘laughing gas’ and used as an anesthetic. It is produced naturally in the rainforests and oceans. Man-made sources include the use of fertilizers in agriculture, nylon, nitric acid production, car with catalytic converters and the burning of organic matter. It is broken down in the atmosphere by chemical reactions driven by the Sun.
Sulfur hexafluoride is a potent man made, greenhouse gas with a lifetime of more than a thousand years. Because of this, a small amount can have a significant impact on global climate change. It is primarily used in the electrical industry in high voltage circuit breakers, switchgear and in the magnesium metal casting industry.
Although the Earth’s atmosphere consists primarily of nitrogen and oxygen, and these greenhouse gases are trace in comparison, they influence the Earth’s climate. 15
Climate Change and its Impact
The effects of global climate change are evident in our environment and climate influences ecosystems. This also means that as the climate changes, ecosystems are affected in a variety of ways. It affects ecosystems and their species directly as well as interacts with other human stressors like development that can lead to dramatic changes. Current food webs and ecosystems can be transformed by climate as it alters where a species may live, how they interact and the timeline of seasonal events. For example, for many species, the climate where they live influences stages in their life cycle in terms of migration, blooming and reproduction, but the timing of these events change as winters are shorter and milder. Earlier springs also change the nesting periods for various bird species which shifts migration timing. Since different species vary in their ability to adjust to such changes in the ecosystem, the ecosystem becomes vulnerable and asynchronies can develop like migration timing, breeding, pest avoidance and food availability all of which can alter growth and survival rates. For instance, warming can force species to move to higher elevations where they can better adapt and survive. Similarly, with the rise of sea level saltwater intrusion into a freshwater ecosystem may force some species to relocate or die. This then can cause a disruption in the existing food chains by removing predators or prey that currently exist there. Mountain and arctic ecosystems in particular are very sensitive to climate change. The rate of species extinctions especially in these sensitive regions could greatly increase with projected warming. Climate change also overwhelms the capacity of ecosystems to mitigate extreme events like wildfires, floods or droughts. Ecosystems can act as natural buffer to such events, but climate change can hamper its ability to deter the impacts making it more susceptible to damage. Some examples include reefs and barrier islands that protect the coastal ecosystems from storm surges, wetlands absorbing floodwaters and cyclical wildfires that help clear forest debris, preventing larger fires.
In addition to ecological shifts, agriculture and fisheries are affected because they are highly dependent on climate. Climate change can make it difficult to grow crops, raise animals and catch fish. As temperature and carbon dioxide levels rise, some crop yields rise, while with more severe warming floods and droughts will reduce the yields. The severity of droughts and floods challenge farmers and ranchers and also can threaten food safety. Livestock can be at risk due to heat stress and reduced quality of their own food supply. Warmer water temperatures can cause shifts in habitat ranges in fish and shellfish which can disrupt ecosystems. Fisheries are affected by the changes in water temperatures that make waters more open to invasive species and shift life cycle timing for some species of fish.
We are all vulnerable to the impact of climate change on our health. Warmer climate is said to increase the risks of illnesses from extreme heat and poor air quality and can expose more people to diseases by supporting the spread of pathogens and parasites. Changes in the air we breathe due to warmer temperatures worsens air quality that can lead to asthma attacks, and other respiratory and cardiovascular issues in addition to changes in allergens and allergic illnesses. Exposure to extreme heat can lead to heat stroke and dehydration as well.16
Human Impact
As we can see global climate change affects us as individuals as well as the ecosystems in which we are a part of, ranging from air quality and the food we eat to a broader scale of the existence of species in an ecosystem and natural disasters. Because of the impact, it is vital to examine human practices and our contribution to the changing so to better understand the budget and proactively plan to stay below projected means. Human activities are impacting the climate system. Scientific studies on climate indicates that most of the increase in global average temperatures are likely due to increases in greenhouse gas concentrations from the burning of fossil fuels. As a result, the amount of carbon dioxide in the atmosphere is rising. These gases are projected to remain in the atmosphere for hundreds of years before being removed through natural processes. Global climate patterns are being altered also by reducing forest cover, the rapid expansion of farming development and industrial activities. Although the ocean absorbs much of the carbon released during the burning of fossil fuels, the extra carbon is lowering the oceans pH in what is known as ocean acidification which interferes with marine organisms.17
What Can We Do?
Climate change is a challenging problem where our lives, species and ecosystems as well as the viability of the economy and future habitability is at stake. Although climate change cannot be stopped it can be slowed. In order to avoid the worst consequences, it is necessary to reach a net zero carbon emissions by 2050 at the latest. This means that the amount of carbon released into the atmosphere is equal to or less than what is taken out. In order to reach this goal, there needs to be a transformation in how electricity is produced and consumed, a better transportation system, an end to deforestation and a climate friendly agricultural system. In order to make such changes a reality, significant federal policies enabled. This is a global issue and therefore requires international agreement.
More than just reducing emissions is needed to address this global issue. Carbon dioxide needs to be actively removed from the atmosphere. This can be done by both afforestation or reforestation and enhanced land management practices. Enhancements in technology can also help where carbon dioxide in air can be captured or prevented from leaving smokestacks. These are expensive fixes and the scale and speed of taking action is important, dependent on strong state and federal policies and investment into research and development. Cutting carbon may be a long-term solution, but until then we need to adapt, which means discouraging development in high-risk areas, building resilient communities and planning ahead for water scarcity. From there we need to act. In addition to seeking out government leaders and supporting activists’ groups.18
In addition to becoming more politically active and letting your local, state and national leaders know that you support action that will decarbonize the country, there are steps that you can do to help reduce your carbon footprint. Simple changes to your daily lifestyle can go a long way if everyone pitches in over time. Some things you can do include altering your diet. Eating mostly fruits, veggies, grains and beans can make a difference, since meat and dairy are responsible for about 14.5 percent of manmade global greenhouse emissions due to feed production, processing and the methane released from livestock. Choosing organic and local foods that are in season also helps, because transporting food uses fossil fuels and fuel for cooling to keep food safe. Reducing food waste by freezing and reusing, as well as composting food waste contributes to the reduction of your carbon footprint. Other fixes include daily habits like clothing. Buying trendy clothing that comes and goes quick, adds to the landfills as well as requires fossil fuels for the transportation of the garments. You can choose recycled clothing from consignment shops instead. Washing your clothes is cold water instead of hot reduces the amount of carbon dioxide. Other related helps include buying less stuff, recycling more often and using reusable bags, avoiding excess packaging and looking for energy efficient products when buying electronics, appliances, lighting or office equipment. You can reduce your carbon footprint in your own home by switching from incandescent lightbulbs to LED. Although they cost more, they last longer and use only ¼ of the energy. Other simple changes including turning off lights and unplugging devices when not in use, turning down your thermostat and using less air conditioning. If you have a water heater, simply turning it down to 120 degrees Fahrenheit can save more than 500 pounds of carbon dioxide a year. Installing a slow flow showerhead and taking shorter showers also helps. Transportation is also a great contributor to carbon dioxide emissions because electricity comes from natural gas and renewable energy. Some changes you can make is to drive less: walk or use public transportation when necessary. Combine your errands into less trips, to reduce driving. If possible, choose a hybrid or electric vehicle. When flying choose nonstop flights when possible and economy class. These are simple steps that can be made to help reduce the carbon budget that if done collectively can make a big impact.19
