The climate system of Earth is a very complex system involving many variables.
However, there are five principal components that make up Earth’s climate system; the sun, the oceans, the atmosphere; the topography and configuration of land masses. The Sunis the primary source of Earth’s energy. When it comes into contact with the atmosphere, the sun’s energy convects through the air until it reaches the surface. 30% of this energy is reflected back into space by clouds, ice, etc. Rotation of the Earth results in the day/night cycleTilt of Earth’s axis towards or away from the sun is what causes seasons.
Variations in the amount of solar radiations can even cause ice ages.Eccentricities in Earth’s orbit around the sun results in changes in the amount of radiation Earth receives. There is a 3.4% distance between the aphelion and perihelion, but solar radiation can vary by 6.8%. OceansMost of sun’s heat that reaches earth absorbed by oceansOceans take longer to heat/cool better than land.
This means that coastal areas stay cooler in summer and warmer in winter.When water in oceans evaporate, winds can carry this evaporation long distances, thus oceans are the source of most precipitation90% of precipitation falls back over the oceanOcean currents also redistribute the warm water from the tropics towards the poles. Ocean currents usually flow clockwise in the Northern Hemisphere and counterclockwise in the southern Hemisphere.Currents caused by surface winds but also partly by temperature ,salinity and tidesOffset uneven distribution of the earth’s heat.
If currents did not exist, temperatures on earth would be much more extreme, hotter at the equator and colder towards the polesMuch less of earth would be habitableAtmosphereThe atmosphere keeps the Earth warm with a process called the greenhouse effect. Acts like an insulator to keep heat trapped in the EarthWithout the greenhouse effect, Earth would be uninhabitable Examples of greenhouse gases include water vapor, carbon dioxide, methane, nitrous oxideAmount of greenhouse gases in Earth’s atmosphere has increased over the last 150 years, particularly CO2 Increase in amount of greenhouse gases leads to more radiation being trapped within Earth and a subsequent rise in temperaturesIn addition to trapping heat, a thin layer in the stratosphere called the Ozone layer reflects harmful UV radiation into spaceThe ozone layer primarily consists of O3The ozone layer can be depleted by man made chemicals, especially ones containing chlorine or bromine. These are typically called Ozone Depleting Substances(ODS)Many ODS are not harmful in the lower atmosphere or on Earth’s surface however, they are able to move into the stratosphere where they are broken down by UV radiation into chlorine and bromine. These chemicals rip atoms off of the ozone layer which leads to its depletionTopographyTopography is the landscape or physical features in an areaMountains can have big effects on climateLand at higher elevations are naturally due the environmental lapse rate.
Air cools at 3.5 degrees Fahrenheit for every 1,000 feet you go up.This is because of the pressurization of air at different altitudes.
When your compress a substance, its particles move faster and more heat is produced. At higher altitudes, the air pressure is lower and thus the temperature is lowerMountains are also barriers to wind movementMountains can force winds up and over their slopes.The air then cools at the higher altitudes.Water Vapor particles in cool air moves less and thus clump together into water droplets(condensing). Land on the side of mountains receiving this dryer air are often very arid and dry.As mentioned before, areas near water bodies often have milder climates and more precipitationDry, arid areas also heat up quicker than wetter areas and then lose much of this heat at nightThis is due to the lack of moisture in the air which would otherwise trap heatConfiguration of Land MassesLand gains and loses heat faster than either air or waterLatitude can determine the amount of solar radiation received, due to the tilt of the EarthThe further away from the equator one gets, the less radiation will be receivedHeat Transfer in Hydrosphere and AtmosphereOcean currents are created by different factors working together. The direction and speed of the wind, breaking waves, temperature and salinity of the water and the coriolis effect.Sources of Greenhouse GasesNaturalCarbonPlant and animal respiration: Respiration releases carbon dioxide into the atmosphere.
Decomposition: During cellular respiration, glucose and oxygen are changed into energy and carbon dioxide is produced as a by productVolcanic eruptions: Massive amounts of ash and debris can be spewed into the atmosphere by volcanic eruptionsMethaneTermites: A single termite can produce about half a microgram of methane a day. This adds up to 20 million tonnes each year coming from termites.Wetlands: Wetlands are water logged.
Thus the local wildlife has adapted to the constant presence of water. The microbes in wetlands consume oxygen more rapidly than it can disperse, and thus the conditions are ideal for fermentation.Water VapourWater bodies: Evaporations from bodies of water is the main source of water vapour emissionsNitrous OxideSoils: Biological processes in soil, particularly tropical soil, result in the release of 6mt/a of nitrous oxideAnthropogenicCarbonBurning of fossil fuels: When carbon rich fuels are burned, carbon is released as CO2Deforestation:Trees and other plants absorb carbon dioxide from the atmosphere. They then convert this into carbon and store it. When these trees are deforested, they release the stored carbon, actually making them become a sourceMethaneLivestock: Methane is produced in the guts of ruminant animals as a result of microorganisms living there.
Landfills: Decomposing waste releases methane and carbon. Landfills ae the third largest anthropogenic source of methane in the United StatesNitrous Oxide40 percent of nitrous oxide emissions are anthropogenicFertilizer use can artificially increase nitrogen concentrations in soil or water and subsequently lead to higher emissions.HalocarbonsHalocarbons are entirely anthropogenically produced and do not occur naturally. Eg. aerosol propellant, refrigerator coolant and air conditionersSinks of Greenhouse GasesNatural CO2Plants: During photosynthesis, plants absorb carbon dioxide and emit oxygen. About 25% of human carbon emissions are absorbed by plantsOceanic sinks: oceans absorb carbon directly from the atmosphere on their surfaces.
Phytoplankton consume this surface carbon and when they die it sinks to the ocean floor. About 25% of human carbon emissions is absorbed by the ocean. MethaneHydroxyl radicals(OH): absorbs atmospheric methane via oxidation to form water and CO2Anthropogenic CarbonCarbon Sequestration: The process of removing carbon from the atmosphere or other sources like smokestacks, and storing it in a secure location This carbon can then be stored by:Direct injection of liquid carbon into oceansInjecting it into underground geological formationsTrapping the carbon in solid carbonate saltsEffects of Climate ChangeIn CanadaOne of the effects of climate change that can be felt here in Canada is warmer and warmer climate. Over the 62 years, mean temperatures in Canada have risen by 1.4°C. In addition, mean winter temperatures have risen 2.
4°C and spring temperatures have risen 1.8°C. Higher temperatures year round, and especially in the winter, can have great effects on the survival of plant and animal species.
For examples, warmer climates may disrupt animals hibernation cycle. In addition to this, the United States faces similar temperature increases as Canada. If American wildlife migrated northwards into Canada to flee warmer temperatures, they may become invasive species which would only disrupt the environment more.
Canada has signed onto the Copenhagen Accord and Kyoto Protocol. In these, it pledges to decrease carbon emissions by 17%. While this may seem a large amount, it is miniscule compared to the 30% pledged by the EU or 40% pledge by China. In fact it is one of the lowest pledges. Despite this, Canadian carbon emissions have been dropping since 2003 from 17.46 metric tons to 13.53 metric tons, and continue to drop.
Apart from international agreements, the Canadian government has often pledged to decrease fossil fuel reliance. However, it is unlikely that there will be any large steps that would negatively affect the energy or mining industries which are some of the largest contributors to the Canadian GDP.Desertification-North AfricaDrylands occupy 40–41% of Earth’s land area and over 2 billion people live in these areas. These people are increasingly under threat of drought. Warmer temperatures can amplify the impact of drought. Higher temperatures increase evaporation from soil, making drought worse than what they would have been in cooler climates.
This dry, arid, dusty and plantless land will further decrease rainfall in a sort of feedback loop. It has been estimated that some 10–20% of drylands are already degraded. Indeed the Sahara desert has increased by 6000 km2 in the past century. The United Nations Convention claims that about six million people in the Sahara region will need to leave their homes between 1997 and 2020. It is estimated that Africa has lost 650 000 km² of arable land in the past 50 years.
All this desertification and greater chance for drought not only poses a threat to the people in the region, it could spark a massive migrant crisis.Reforestation programs are perhaps the best solution to the desertification problem. Trees and other vegetation hold down the soil underneath them and help prevent erosion. The shade provided will also decrease evaporation in soil.
In China, they have begun to start planting a 4,500 km long forest strip known as the Three-North Shelter Forest Program, or colloquially “The Great Green Wall”. Scheduled to be finished in 2050, how successful it will be remains to be seen. In Africa a similar program is being developed for the Sahara. However, rather than building an artificial forest, African states are pushing for local farmers to care for surrounding forests and to practice positive agriculture practices, such as proper irrigation and crop rotation, in order to sustain the health of the soil. Unfortunately, without greater government support and incentives it is unlikely that african farmers will fully adopt good agricultural practices.
However the long term effectiveness of programs like these remains to be seen.Flooding-South East AsiaOceans absorb 80% of the heat that reaches the Earth, Thus, as temperatures rise worldwide, the rate of evaporation will rise alongside it. Increased evaporation will lead to increased rainfalls. In areas such as south east Asia where seasonal monsoons already devastate areas on a regular basis, increased rainfalls will only add to the destruction.
In addition to increased rainfall, rising temperatures threaten to melt polar ice caps. This could substantially increase sea levels which would threaten coastal areas worldwide. On top of that, warmer water expands and we can attribute about half of sea level rise to this thermal expansion The National Climate Assessment estimated a sea level rise of 1 to 4 feet by 2100.
As sea levels reach further inland, it can cause erosion, soil contamination, and lost habitat for fish, birds, and plants. Millions of people that live in areas that will become more vulnerable to flooding. Many of them will be forced to relocate.An issue as widespread as this requires a similarly international response. The Paris Climate Accord, signed by 195 nations, is by far the largest and most united push against climate change to date. Its objectives are:(a) Holding the increase in the global average temperature to well below 2°C above pre-industrial levels and to pursue efforts to limit the temperature increase to 1.5 °C above pre-industrial levels, recognizing that this would significantly reduce the risks and impacts of climate change;(b) Increasing the ability to adapt to the adverse impacts of climate change and foster climate resilience and low greenhouse gas emissions development, in a manner that does not threaten food production;(c) Making finance flows consistent with a pathway towards low greenhouse gas emissions and climate-resilient development.Since it was signed in April of 2016, national governments have already started to implement policies to achieve the set goals.
However the current pledges made by nations are not sufficient to meet the “well below 2?” goal it has set out. In fact all major developed nations are failing to meet the promises made in the agreement. The biggest downfall of the Paris Climate Agreement is its lack of firm commitments. Everything the nations have pledge or simply promises and may be broken. There is no better example than the US who have stated they intend to pull out of the agreement after the election of President Donald Trump.
Factors Affecting the Climate Natural and AnthropogenicGreenhouse effectThe greenhouse effect is a natural phenomenon where radiation from the atmosphere increases the surface temperature above what it would be without the atmosphere. When solar radiation first reaches our atmosphere, some of it is reflected away while the rest reaches the surface. After reaching the surface, this heat is then radiated back into space. Gases in our atmosphere, called greenhouse gases, radiate some of this heat back towards Earth. This ensures that not all of the heat that Earth receives is immediately lost into space.
Without the greenhouse effect, Earth’s average temperature would be ?18 °C, 33 °C lower than the current average. The highest contributors to the greenhouse effect are: water vapor with 36–70%, carbon dioxide(9–26%), methane(4–9%), and ozone(3–7%). Accurately estimating the input of each gas is difficult due to overlap in their heat absorption. In recent history, humans have been increasingly adding to global warming by emitting large amounts of greenhouse gases like CO2 and methane. Larger amounts of greenhouse gases leads to more heat being radiated back to earth and subsequent temperature increase.
Since 1959, the amount of carbon in the atmosphere has increased from 315 ppm to 387 ppm and in the last century, the average temperature on earth has increased by 0.8 ?.NaturalVolcanic EruptionsVolcano eruptions spew out massive amounts of sulphur dioxide, water vapour, dust, and ash into the atmosphere.
These relatively short eruptions can influence global climate for years. The dust and ash from the eruption blocks out sunlight and leads to cooling throughout the globe. In addition to the ash, sulfur dioxide is introduced into the atmosphere and combines with water to form sulfuric acid aerosis. The sulfuric acid forms a haze of droplets in the atmosphere that reflects radiation, adding to the cooling effect. The droplets can stay in the atmosphere for as long as three years.
Over time the droplets become large enough to fall back to Earth. An example of climate change caused by a volcano is the 1815 eruption of Mount Tambora in present day Indonesia. The eruption is one of the largest in history, and is the only confirmed eruption with a Volcanic Explosivity Index of 7. The resulting blockage of sunlight led to a decrease in global temperatures of 0.4–0.
7 °C, almost the same amount of change recorded from global warming in the last 100 years. 1816 was dubbed “The Year Without a Summer” due to temperature decreases that led to cold temperatures year round in the northern hemisphere. 12 inches of snow had been reported to have fallen in Quebec City in the month of June. However, these conditions did not last forever. After the dust and ash had dissipated, global temperatures recovered to their normal amounts. It would take an eruption as large as the one mentioned here to alter global climate. Most eruptions do not produce enough ash or project it high enough to have worldwide and long term effects.
AnthropogenicDeforestationTrees are some of the most wide spread carbon sinks. Forests are also extremely important to the wellbeing of an environment. They prevent leaching, erosion and desertification. About 30% of the Earth’s landmass is covered by forests. However, forests are being cut down at an alarming rate. At the current rate of deforestation, tropical rainforests will be completely wiped out within a century. Deforestation is estimated to release over 1.5 billion tons of CO2 every year.
So deforestation not only removes natural carbon sinks, it actually directly adds to carbon emissions, which contributes to the greenhouse effect. After an area has been cleared of trees, the soil will be more vulnerable to erosion and its nutrients will be more likely to be washed away. Deforestation also affects the water cycle. Trees extract water from the ground through their roots and then release it into the air. When these trees are removed, the trees no longer bring out this water and the result is a much more arid local climate.
Additionally, forests are able to trap precipitation in the soil, which is then absorbed and transpired, so that it stays in the water cycle. When forests are removed, the soil loses much of its ability to retain water and it is lost as runoff. Because this water is no longer transpired into the atmosphere, the amount of precipitation in that area will decrease.