Geography ch 10 review

Three most common formation mechanisms for temp inversions

1) Overnight radiative cooling of the Earth's surface and lower atmosphere. 2) The intrusion of a cold mass of air under a warm mass. 3) The downslope subsidence of cool air from areas of higher elevation on a mountain

how do faster wind flows increase the dilution of air pollution?

1) faster winds spread the pollution over a much larger are downstream per unit time 2) faster winds are often more turbulent and this increase the vertical diffusion of the emission

Atmospheric stability

The capacity of the atmosphere to mix and disperse air pollutants is also influenced by atmospheric stability. Atmospheric stability refers to the ability of relatively small air parcels to ascend upward in the atmosphere. If the atmosphere encourages the development of vertical air currents, we call it unstable. A stable atmosphere has limited vertical movement of air. Accordingly, unstable atmospheric conditions are more favorable for dispersing air pollutants to higher altitudes. We can quickly determine the stability of the atmosphere by observing the behavior of smoke released from a chimney or smoke stack

The chemical nature of the atmosphere and its effect on the Earths climate

The chemical nature of the atmosphere is an important factor in determining the Earth's climate. Heat energy from the Sun is trapped in the Earth's lower atmosphere by a natural process called the greenhouse effect. The amount of heat trapped depends primarily on the concentrations of the various greenhouse gases, such as carbon dioxide, water vapor, ozone, methane, and nitrous oxide. The two greenhouse gases with the largest concentration in the troposphere are carbon dioxide and water vapor. Over the past 160,000 years, estimated levels of water vapor in the lower atmosphere have remained fairly constant while the levels of carbon dioxide have fluctuated in-sync with the warming and cooling of the Earth

How is ozone created and destroyed?

Ozone is created naturally in the stratosphere by the joining of atomic oxygen (O) with molecular oxygen (O2). This process is activated by sunlight. Ozone is destroyed naturally by the absorption of ultraviolet radiation, O3 (ozone) + UV -> O2 (molecular oxygen) + O (atomic oxygen) and by the collision of ozone with other atmospheric atoms and molecules. O3 (ozone) + O (atomic oxygen) -> 2O2 (molecular oxygen) O3 (ozone) + O3 (ozone) è 3O2 (molecular oxygen)

Particulate matter

Particulate matter consists of liquid or solid particles that are small enough to remain suspended in the atmosphere for long periods of time.

Formation of photochemical smog

Photochemical smog requires the primary pollutants of nitrogen oxides (NOX) and volatile organic compounds (VOCs) for formation. High concentrations of these two substances are often found in large urban areas with heavy industrialization and high levels of transportation. Industrialization and transportation create these pollutants mainly through the combustion of fossil fuels. Nitrogen oxide and volatile organic compound concentrations, and the chemical reactions involving these substances cycle on a daily basis with steady regularity.

Temperature inversions

Temperature inversions develop when a layer of warm air sits on top of cooler air (Figure 10.8). The presence of such a layer limits vertical atmospheric mixing and therefore reduces the potential for the dispersion of pollutants. Temperature inversions can form under a variety of circumstances.

Some possible environmental effects that could arise from this worst-case scenario level of global warming are as follows (IPCC, 2014): Plants, Animals, and Biome Changes

The geographic extent of Earth's major biomes will change. Some biomes like the tundra will shrink, while others like the tropical rain forest will expand. • The area occupied by the present North American grasslands may receive less rainfall increasing the frequency and severity of drought. This will also result in changes in species dominance favoring organisms that can better withstand scarce water availability. • Coniferous forests of Alaska, Canada, and Russia will move further north into areas now occupied by tundra as climates become milder. • Many animals and plants will be forced to migrate and change their geographic range to compensate for a warmer climate and changes in precipitation patterns. Those that cannot migrate may become extinct. • Changes in geographic range of plants and animals will be most severe in the higher latitudes because of the greater change in temperatures and possibly precipitation patterns. • More of our planet's coral reefs could be destroyed because of rising sea temperatures. • Organisms living in relatively isolated mountains and mountain ranges will be extremely limited in their ability to migrate to find suitable new habitats. • Species composition of inland fisheries will change as lakes and streams get warmer and as stream discharge changes.

The ozone layer

The ozone layer is a region of concentration of the ozone (O3) molecule in the Earth's atmosphere. The layer sits at an altitude of about 10 to 50 km (6 to 31 mi), with a maximum concentration in the stratosphere at an altitude of approximately 25 km (16 mi) (Figure 10.30). In recent years, scientists have measured a seasonal thinning of the ozone layer primarily at the South Pole. This phenomenon is known as the ozone hole.

the industrial revolution

The Industrial Revolution is the underlying cause for the increase of pollutants in the atmosphere over the last three centuries. Before 1950, air pollution was mainly created from the burning of coal for energy generation, space heating, cooking, and transportation.

Photochemical smog

The burning of fossil fuels like refined gasoline can create another atmospheric pollution problem known as photochemical smog. Photochemical smog develops when primary pollutants that include oxides of nitrogen and volatile organic compounds chemically react under the influence of solar radiation. This reaction produces a mixture of hundreds of different and toxic secondary pollutants.

wind and its role in diffusing air pollution

Wind has an important function in diffusing air pollution downwind from its source. The rate of dilution is directly controlled by wind speed. The absolutely worst condition for air pollution is when the wind is calm.

two most common gases in our planets atmosphere

nitrogen and oxygen

The effects of acid deposition on humans

Can be divided into 3 main categories: Health effect, economic effects and damage in inanimate objects

The effects of acid deposition on humans: Economic effects

Acid deposition also influences the economic livelihoods of some people. Many lakes and streams on the eastern coast of North America are so acidic that the fish have declined significantly in numbers. The reduced fish numbers then influence commercial fishermen and industries that rely on sport fishing tourism. Forestry and agriculture are influenced by the damage caused to vegetation. In some areas of eastern North America and Europe, large diebacks of trees have occurred.

How can acid deposition form?

Acid deposition can form as a result of two processes. In some cases, hydrogen chloride (HCl) can be expelled directly into the atmosphere by volcanoes. Mixing hydrogen chloride with water forms hydrochloric acid. More commonly, acid deposition is produced from secondary pollutants that form from the oxidation of nitrogen oxides (NOX) or sulfur dioxide (SO2) gases that are released into the atmosphere. Reactions at the Earth's surface or within the atmosphere can convert these pollutants into nitric acid (HNO3) or sulfuric acid (H2SO4) (Figure 10.15). The process of altering these gases into their acid counterparts can take several days and during this time these pollutants can be transferred hundreds of kilometers (miles) from their original source. Acid precipitation formation can also take place at the Earth's surface when nitrogen oxides and sulfur dioxide settle on the landscape and interact with dew or frost

Effects of acid deposition

Acid deposition influences the environment in several different ways. In aquatic systems, acid deposition can influence these ecosystems by lowering their pH. Yet, not all aquatic systems are affected equally. Streams, ponds, or lakes that exist on bedrock or sediments rich in calcium (Ca) and/or magnesium (Mg) are naturally buffered from the effects of acid deposition. Aquatic systems on neutral or acidic bedrock are usually very sensitive to acid deposition because they lack basic compounds to buffer acidification

Acid deposition

Acidic pollutants can be deposited from the atmosphere to the Earths surface in wet and dry forms. The common term used to describe this process is acid deposition.

what happens to sulfur after it is released into the atmosphere

After being released into the atmosphere, sulfur dioxide can either be deposited on the Earth's surface in the form of dry deposition or it can undergo the following reactions to produce acids that are incorporated into the products of wet deposition (see Figure 10.15): SO2 (sulfur dioxide) + H2O (water) -> H2SO3 (anhydride) H2SO3 (anhydride) + 1/2O2 (molecular oxygen) -> H2SO4 (sulfuric acid)

Air pollution

Air pollution is an atmospheric condition where the concentration of certain substances becomes high enough to cause toxicity to life, damage to inanimate things, or a change in natural atmospheric processes. Air pollutants can be gaseous, liquid, or solid in form. Further, these substances can come from natural processes as well as human sources. Examples of naturally created air pollution include the gases and solid particles released from forest fires, pollen from plants, spores, methane and hydrogen sulfide gas from decaying organic matter, volcanic emissions, and wind blown dust. Air pollutants of human origin are generated by industry, agriculture, forestry, transportation, power generation, and space heating.

paris agreement

At the twenty-first Conference of the Parties meeting in Paris, France (occurring from November 30 to December 11, 2015), the Paris Agreement was negotiated and afterward signed by 177 parties (nation states) on April 22, 2016 (Earth Day). The main goal of this latest climate change treaty is to create a legally binding second commitment agreement to decrease and eventually eliminate human caused greenhouse gas emissions, and to restrict future annual mean global temperature increase to well below the important 2.0°C pre-industrial level threshold identified by climate scientists. Specifically, nations signing and ratifying the Paris Agreement will make a concerted effort to try to limit global warming to just 1.5°C above the pre-industrial level. This focus on limiting future temperature increase is quite different from the Kyoto Protocol which dealt with only minor reductions to greenhouse gas emissions.

Some possible environmental effects that could arise from this worst-case scenario level of global warming are as follows (IPCC, 2014): Changes to the weather and climate

Average annual temperatures would be 3 to 7°C (5 to 13°F) warmer in mid-latitude land locations and about 5 to 11°C (9 to 20°F) warmer in the Arctic. • A warmer planet would increase evaporation of water and this should lead to higher quantities of precipitation for many parts of the world (Figure 10.29). Climatologists have already documented a 10% increase in precipitation over the middle and higher latitudes of the North Hemisphere from 20th century global warming. • Hurricane intensity and frequency would increase in tropical and subtropical regions. Southeast Asia and Central Africa may experience stronger monsoons that would produce more precipitation in some parts of these areas. • An increase in the frequency of severe thunderstorms in mid-latitudes raising the likelihood of tornadoes, hail, and flooding.

sulfur oxides

Burning sulfur-rich fossil fuels, like oil and coal, produces a group of air pollutants known as sulfur oxides (SOX). Sulfur dioxide (SO2) is the most common form of these pollutants. Sulfur dioxide is a colorless gas that has a pungent, irritating odor at concentrations above 3 ppm. The most common sources for human generated sulfur dioxide include smelters, petroleum refineries, power plants, and other industrial processes that burn oil or coal (Figure 10.3). Annually, about 20 million metric tons of SO2 are released into the atmosphere by human activities in just the United States. Emissions of sulfur dioxide can also be of natural origin. Some volcanic eruptions emit significant quantities of this gas over short periods of time. It can also be released from the decay or combustion of organic matter. Sulfur dioxide gas can react in the atmosphere to form sulfur trioxide (SO3) and sulfuric acid (H2SO4). We will discover later in this chapter that sulfuric acid is a major component in acid deposition.

Carbon monoxide

Carbon monoxide (CO) is a colorless, odorless gas that is highly toxic. It is often produced by the incomplete combustion of compounds and fuels containing carbon. Internal combustion engine exhaust normally contains high concentrations of this gas (Figure 10.2). Carbon monoxide is also created naturally from sources like the decay of organic matter in wet environments. Natural sources account for 93% of the emissions released into the atmosphere. However, these emissions are generally not harmful because they are geographically very dispersed. Emissions from human activities tend to be harmful because these sources are concentrated spatially in cities in close association with dense human populations.

Global Climate Models (GCMs)

Climate researchers often use complex computer models, called Global Climate Models (GCMs) to mathematically predict the past or future state of the Earth's climate. When these GCMs are modeled with the effects of higher greenhouse gas concentrations in the atmosphere, they almost always predict a warmer global climate. Since the beginning of the 20th century, Earth's annual mean global temperature has increased by about 0.9°C (1.6°F). Many climatologists believe this increase, or global warming, may be evidence that the greenhouse effect is being enhanced by higher greenhouse gas concentrations, producing more heat energy and higher Earth temperatures.

Main sources of sulfur

Coal burning - coal typically contains 2-3% sulfur so when it is burned sulfur dioxide (SO2) is released. • The smelting of metal ores rich in sulfide to obtain the pure metals. Metals such as zinc (Zn), nickel (Ni), and copper (Cu) are all commonly obtained in this way. • Volcanic eruptions - though this is not a common and widespread problem, a volcanic eruption can add a lot of sulfur (S) to the atmosphere in a regional area. • The decay of organic matter. • Ocean spray

Clean air acts

Congress passed Clean Air Acts in 1970, 1977, and 1990. This legislation establishes air pollution regulations that are enforced by government agencies at federal, state, and municipal levels. Canada has similar laws that are regulated at federal and provincial levels of government.

The effects of acid deposition on humans: Inanimate objects

Finally, acid deposition can also damage inanimate things. Buildings and head stones that are constructed from limestone are readily dissolved by acid, while structures that are constructed of iron or steel can be corroded (Figure 10.18). Paint on cars can react with acid deposition causing fading.

the Montreal protocol

In 1987, a number of nations around the world met to begin formulating a global action plan, known as the Montreal Protocol, to reduce and eliminate the use of CFCs. Since 1987, the plan has been amended seven times to accelerate the schedule of production and consumption reductions of CFCs and other related chlorinated hydrocarbons (London, 1990; Nairobi, 1991; Copenhagen, 1992; Bangkok, 1993; Vienna, 1995; Montreal, 1997; and Beijing, 1999). By September 16, 2009, all of the countries belonging to the United Nations were participating in the original Montreal Protocol. This legal agreement called for a 100% reduction in the creation and use of CFCs by January 1, 1996 in the world's more developed countries. Less developed countries had until January 1, 2010 to stop their production and consumption of these dangerous chemicals. Each successive amendment has fewer nations participating. The last amendment (Beijing, 1999), only has 154 countries engaged in its stipulations.

How is particulate matter air pollution monitored in Canada and the USA

In Canada and the United States, particulate matter air pollution is monitored in two size groups: particles smaller than 2.5 µm in diameter (called PM2.5) and particles smaller than 10 µm in diameter (called PM10) (Figure 10.4). Particulate matter includes common naturally produced irritants like smoke, pollen, and dust (Figure 10.5). These particular irritants can harm the human respiratory system at high concentrations, making breathing difficult for people with asthma and other chronic respiratory diseases.

Acid shock

In the middle latitudes, many acidified aquatic systems experience a phenomenon known as acid shock. During the winter the acidic deposits can build up in the snowpack. With the arrival of spring, the snow-pack begins to melt quickly and the acids are released over a short period of time at concentrations 5 to 10 times more acidic than rainfall. Most adult fish can survive this shock, but the eggs and small fry of spring spawning species are extremely sensitive to this acidification.

impact of acid deposition on vegetation

In the middle latitudes, many acidified aquatic systems experience a phenomenon known as acid shock. During the winter the acidic deposits can build up in the snowpack. With the arrival of spring, the snow-pack begins to melt quickly and the acids are released over a short period of time at concentrations 5 to 10 times more acidic than rainfall. Most adult fish can survive this shock, but the eggs and small fry of spring spawning species are extremely sensitive to this acidification.

Acids of nitrogen form as a result of what?

NO (nitric oxide) + 1/2O2 (molecular oxygen) -> NO2 (nitrogen dioxide) 2NO2 (nitrogen dioxide) + H2O (water) -> HNO2 (nitrous acid) + HNO3 (nitric acid) NO2 (nitrogen dioxide) + OH (hydroxyl) -> HNO3 (nitric acid)

Recommendations to create a clean atmosphere

Prevent pollution emissions rather than controlling them. • Improve energy efficiencies. Less fuel burned means lower emissions. • Use cleaner fossil fuels. Replace coal and oil with natural gas which contains virtual no emissions of SO2 and NOX. • Develop and increase the use of nonpolluting energy sources like solar energy, wind power, and hydropower. • Encourage mass transit and less polluting forms of transportation (e.g., switch from air travel to rail travel). • Slow human population growth. Less people means less energy needs. • Include environmental costs in the pricing of energy resources and other activities that produce atmospheric pollution. • Some types of indoor pollution can be reduced by the modification of building codes. These modifications can be used to control materials used in construction and to ensure proper building ventilation.

Categories of pollutants: primary pollutants

Primary pollutants consist of substances (dust, gases, liquids, and other solids) that enter the atmosphere through natural and human-made (anthropogenic) events (Table 10.1). The main primary pollutants influencing our atmosphere are carbon monoxide, sulfur oxides, nitrogen oxides, volatile organic compounds, and particulate matter

main reason for stratospheric ozone destruction

Researchers quickly discovered that the main agent responsible for the destruction of stratospheric ozone was human-made chlorofluorocarbons or CFCs (Molina and Rowland, 1974 and Solomon et al., 1986). First produced by General Motors Corporation in 1928, CFCs were created as a replacement to the toxic refrigerant ammonia. CFCs have also been used as a propellant in spray cans, cleaner for electronics, sterilant for hospital equipment, and to produce the bubbles in styrofoam. CFCs are cheap to produce and are very stable compounds, lasting up to 200 years in the atmosphere. Up to 1988, some 320,000 metric tons of CFCs were used worldwide.

Categories of pollutants: Secondary pollutants

Secondary pollutants are made from primary pollutants that have reacted with each other or with some basic component of the atmosphere to produce a new toxic substance or substances. In cities, the emissions from vehicles and industries combine with the help of light energy from the Sun produce photochemical smog. Photochemical smog consists of a number of different secondary pollutants. It is extremely toxic to animal and plant life, and damages paint, rubber, and plastics.

Meteorological factors and the formation of photochemical smog

Several meteorological factors can influence the formation of photochemical smog. These conditions include: • The chemical reactions involved in the production of photochemical smog need an air temperature greater than 18°C (64°F). Photochemical smog production increases as temperatures rise above this value. • Intense solar radiation is needed to chemically activate the breakdown of nitrogen dioxide (NO2). • Precipitation can alleviate photochemical smog as the pollutants are washed out of the atmosphere with the rainfall. • Winds can blow photochemical smog away replacing it with fresh air. This weather process also causes toxic air problems to the adjacent areas that receive the pollution. • Temperature inversions can enhance the severity of a photochemical smog episode. Normally, during the day the air near the Earth's surface is heated and as it warms it rises, carrying the pollutants with it to higher elevations. If a temperature inversion develops, pollutants can be trapped near the Earth's surface.

Ozone depletion in the stratosphere

Since the late 1970s, scientists have noticed that stratospheric ozone amounts over Antarctica were decreasing every year from September to November. Starting in the 1980s a similar, but less severe, hole over the Arctic began appearing during the months of March to May. In some years, spring levels of stratospheric ozone were more than 70% lower over the Antarctic and 30% lower over the Arctic than the levels recorded before the seasonal development of these holes. During late 1990s, large losses of ozone were recorded above Antarctica year after year in the months of September and October (Figure 10.31). Satellite measurements have also indicated about a 5% decrease in ozone between 65° North - 65° South between 1979 and 2001. A reduction of about 3% per year has been measured at Antarctica where most of the ozone loss is occurring globally.

Harmful effects if we didnt have the ozone layer

The ozone layer naturally shields Earth's life from the harmful effects of the Sun's ultraviolet (UV) radiation. A severe reduction in the concentration of ozone in the ozone layer could lead to the following harmful effects: • Ultraviolet radiation can destroy the acids in DNA and thus lead to an increase in the incidence of malignant melanoma (skin cancer). • A large increase in cataracts and sunburning. • Suppression of immune systems in organisms. • Reduced growth of plants including non-terrestrial phytoplankton found in the Earth's oceans. • Possibly some surface climate effect and a cooling of the Earth's stratosphere because of decreased heat generation from UV absorption.

Acid precipitation

The term acid precipitation is used to specifically describe wet forms of acid pollution that can be found in rain, sleet, snow, fog, and cloud vapor.

Four different future emission scenarios of greenhouse gases according to the Intergovernmental Panel on Climate Change

These emission scenarios are called Representative Concentration Pathway 2.6 (RCP 2.6), 4.5 (RCP 4.5) 6.0 (RCP 6.0), and 8.5 (RCP 8.5) and are based on four assumptions of how future human population growth and socioeconomic development will unfold during the 21st century (van Vuuren et al., 2011). *look at table 10.3* Many scientists believe RCP 4.5 is a most likely outcome than can occur with reasonable future efforts in climate change mitigation by our planet's various nations. RCP 8.5 represents what would happen if very little mitigation took place in the future to tackle climate change.

the kyoto protocol

This legally binding treaty associated with the UNFCCC proposed that industrialized countries would reduce their combined emissions of greenhouse gases by 5.2% relative to 1990 levels sometime between 2008 and 2012. Greenhouse gases included in this agreement were carbon dioxide, methane, nitrous oxide, sulfur hexafluoride, and various types of fluorocarbon compounds. Specific target emission changes included 8% reductions for the European Union and some other countries, 7% for the United States, 6% for Japan and Canada, 0% for Russia, and increases for Australia (8%) and Iceland (10%). Under the terms of the Kyoto Protocol, ratification would only occur if the combined 1990 emissions of countries signing the agreement equaled 55% or greater. On November 18, 2004 this objective was achieved and the Kyoto Protocol was ratified with the signing of Russia and Canada. As of February 2005, a total of 141 countries have ratified the agreement. Yet, there are a few countries that refuse to sign the protocol for a variety of reasons. Two industrial countries from this group include the United States and Australia. The United States refused to sign the agreement for two main reasons: 1) fear that implementing it would cause too much economic damage in the United States, and 2) because the agreement did not require developing countries to commit to emissions reductions.

Topography and air pollution

Topography is another important factor influencing how severe an air pollution event can become. Urban areas situated in valleys are often more susceptible to poor air quality. This is especially true if hills and mountains surround the valley on all sides. Pollution will often sit inside a valley because of the draining effects of cold air during the evening (Figure 10.9). The presence of hills and mountains also reduces airflow that diffuses air pollution by moving it away from its source. Lastly, valleys are often sensitive to air pollution because relatively strong temperature inversions can frequently develop in these areas

The effects of acid deposition on humans: health effects

Toxic metals, such as mercury (Hg) and aluminum (Al), can be released into the environment through the acidification of soils. The toxic metals can then end up in the drinking water, crops, and fish, and are then ingested by humans. If consumed in great quantities, these metals can have toxic effects on human health. • High concentrations of sulfur dioxide (SO2) and oxides of nitrogen (NOX) increase the severity of respiratory ailments like asthma, bronchitis, and emphysema. • Research on children from communities that receive a high amount of acidic pollution show increased frequencies of chest colds, allergies, and coughs.

Consequences of human causes climate change

Under the IPCC's RCP8.5 worstcase scenario, we can expect an increase in annual mean global temperature between 3.6°C to 4.8°C (6.5 to 8.6 °F) by 2100. This level of predicted warming is about 400 to 600% greater than the increase in the global annual mean temperature that occurred during the 20th century.

Industrial smog

Under the right conditions, the smoke and sulfur dioxide produced from the burning of coal can combine with the moisture in fog to create industrial smog (Figure 10.10). In high concentrations, industrial smog can be extremely toxic to humans and other living organisms. London is world famous for its episodes of industrial smog.

Volatile organic compounds

Volatile organic compounds (VOCs) are organic molecules that are mainly composed of carbon and hydrogen atoms (hydrocarbons). Most VOCs are natural in origin. However in cities, emissions of these chemicals from industrial and transportation processes are much greater than natural sources. The most common volatile organic compound released into the atmosphere is methane (CH4). Methane poses no direct danger to human health, but it does contribute to global warming through an enhancement of the greenhouse effect. Other common volatile organic compounds released into the atmosphere include benzene (a common industrial solvent), formaldehyde, and chlorofluorocarbons. Of these chemicals, benzene and formaldehyde are the most dangerous to human health as they are carcinogenic. Another health danger associated with this group of chemicals is organ damage

Nitrogen oxides

when air contain oxygen and nitrogen are subjected to high temperatures, the nitrogen and oxygen react together to form a group of chemical compounds known as nitrogen oxides (NOX). The main human sources of these gases include the burning of fossil fuels for transportation, power generation, and industrial processes. Nitric oxide (NO) and nitrogen dioxide (NO2) are the two most common products of combustion. Of these two forms of nitrogen oxides, NO is slightly toxic while NO2 is highly toxic. Nitrogen oxides have been found to cause lung irritation and damage, aggravation of respiratory diseases, immunity reduction, and have been linked to the spread of cancer. Nitrogen oxides can form naturally from bacterial action, volcanoes, and lightning. In most urban environments, the quantities of nitrogen oxides produced from human activities are many times greater than what is created naturally. In the presence of moisture, nitrogen dioxide can react with water to form highly corrosive nitric acid (HNO3).

The major sources of nitrogen oxides include

• Combustion of oil, coal, and gas. • Bacterial action in soil. • Forest fires. • Volcanic action. • Lightning.

Some possible environmental effects that could arise from this worst-case scenario level of global warming are as follows (IPCC, 2014): Changes to the Hydrology of the Planet

• Rising sea level due to the thermal expansion of the oceans and the melting of glaciers and ice caps could lead to flooding in coastal regions. • Water levels in many lakes could change because of variations in precipitation and evaporation. • Changes in water supply and storage will modify human domestic, industrial, and agricultural water withdrawal and consumption. • Modifications in the flow of runoff may have an effect on hydroelectric power generation. • Most around the world glaciers will continue to retreat. The glaciers on Mount Kilimanjaro, Tanzania, Africa could be completely gone by 2050. • Mountain snow-packs will see reductions that will in turn affect spring and summer supplies of runoff to adjacent lowlands.

Some possible environmental effects that could arise from this worst-case scenario level of global warming are as follows (IPCC, 2014): Human built environment and agriculture

• Urban areas will get warmer and this will increase the need for air conditioning. • Residential heating needs will decrease for many locations on our planet. • Some agricultural practices will have to change because of the lengthening of the growing season and the changes in precipitation patterns. • Warmer temperatures at high latitudes will cause permafrost to melt creating construction problems with homes, roads, and pipelines.

What factors are responsible for temp fluctuations that we experience on Earth

• Variations in the Sun's output of radiation. • Emission of substances into the atmosphere by volcanoes that reduce the amount of sunlight received by the Earth. • Changes in the tilt of the Earth's polar axis. • Variations in the shape of the Earth's orbit around the Sun. • Changes in the timing of when the Earth is closest and farthest from the Sun. • Mountain building and its consequences on atmospheric circulation patterns and surface albedo. • Drifting of the continental landmasses. • Large-scale land-use change such as deforestation and urbanization. • Changes in the chemical nature of the atmosphere.

Some possible environmental effects that could arise from this worst-case scenario level of global warming are as follows (IPCC, 2014): Human health effects

• Warmer temperatures may decrease deaths associated with cold weather. This will be more than compensated by mortality increase associated with extreme heat. Hospital data indicates that mortality rates increase substantially with heat waves. Such heat waves will be more common in many areas of the world. • The risk of tropical and subtropical infectious diseases will increase. Vector-borne diseases including malaria, dengue fever, yellow fever, and encephalitis will spread poleward with their insect hosts.