Untitled Lesson

Environmental Policies and Practices

By Shari Howard

Climate Change and Global Warming

​Climate change is one of the prime issues threatening the world’s environment. Climate change will have wide-ranging effects on the environment, and on socio-economic and related sectors, including water resources, agriculture and food security, human health, terrestrial ecosystems and biodiversity and coastal zones. Changes in rainfall pattern are likely to lead to severe water shortages and/or flooding. Melting of glaciers can cause flooding and soil erosion. Rising temperatures will cause shifts in crop growing seasons which affects food security and changes in the distribution of disease vectors putting more people at risk from diseases such as malaria and dengue fever. Temperature increases will potentially severely increase rates of extinction for many habitats and species (up to 30 per cent with a 2° C rise in temperature).

Open Ended

Describe what could happen if there is a change in rainfall patterns.

​Rising fossil fuel burning and land use changes have emitted, and are continuing to emit, increasing quantities of greenhouse gases into the Earth’s atmosphere. These greenhouse gases include carbon dioxide (CO2), methane (CH4) and nitrogen dioxide (N2O), and a rise in these gases has caused a rise in the amount of heat from the sun withheld in the Earth’s atmosphere, heat that would normally be radiated back into space. This increase in heat has led to the greenhouse effect, resulting in climate change. The main characteristics of climate change are increases in average global temperature (global warming); changes in cloud cover and precipitation particularly over land; melting of ice caps and glaciers and reduced snow cover; and increases in ocean temperatures and ocean acidity – due to seawater absorbing heat and carbon dioxide from the atmosphere Over the next decades, it is predicted that billions of people, particularly those in developing countries, face shortages of water and food and greater risks to health and life as a result of climate change

Multiple Choice

Which of the following is NOT a Greenhouse Gas?

• Carbon dioxide (CO₂)

• Propane (C₃H₈)

• Methane (CH₄)

• Nitrogen dioxide (N₂O)

Open Ended

Explain the Greenhouse Effect.

​“Global warming” refers to the long-term warming of the planet. Global temperature shows a well-documented rise since the early 20th century and most notably since the late 1970s. “Climate change” encompasses global warming, but refers to the broader range of changes that are happening to our planet. These include rising sea levels, shrinking mountain glaciers, accelerating ice melt in Greenland, Antarctica and the Arctic, and shifts in flower/plant blooming times. These are all consequences of the warming, which is caused mainly by people burning fossil fuels and putting out heattrapping gases into the air. The terms “global warming” and “climate change” are sometimes used interchangeably, but strictly they refer to slightly different things.

Multiple Choice

Which of the following is NOT a result of Climate Change?

• Rising sea levels

• Shrinking mountain glaciers

• Shifts in plant blooming times

• More plants growing in the Amazon

Multiple Choice

Which of the following is NOT being affected by accelerating ice melt?

• The Himalayan Mountain glaciers

• Greenland

• Antarctica

• The Artice

Acid Rain

​When fossil fuels such as coal, oil and natural gas are burned, chemicals such as Sulphur dioxide and Nitrogen oxides are released into the air. Acid rain is one of the consequences of air pollution. It occurs when emissions from factories, cars or heating boilers contact with the water in the atmosphere. These emissions contain nitrogen oxides, sulfur dioxide and sulfur trioxide, which when mixed with water becomes sulfurous acid, nitric acid and sulfuric acid. This process also occurs naturally through volcanic eruptions.

Open Ended

Explain how acid rain forms.

​EFFECTS OF ACID RAIN:
1. Acid rain is very harmful to agriculture, plants, and animals. It washes away all nutrients which are required for the growth and survival of plants. Acid rain affects agriculture by the way how it alters the composition of the soil. It causes respiratory issues in animals and humans.

2. When acid rain falls down and flows into the rivers and ponds it affects the aquatic ecosystem. As it alters the chemical composition of the water, to a form which is actually harmful to the aquatic ecosystem to survive and causes water pollution.

3. Acid rain also causes the corrosion of water pipes. Which further results in leaching of heavy metals such as iron, lead and copper into drinking water.

4. It damages the buildings and monuments made up of stones and metals.

Open Ended

Describe 4 effects of acid rain.

OZONE LAYER DEPLETION

​The ozone layer is a layer in Earth's atmosphere which contains relatively high concentrations of ozone (O3). This layer absorbs 93-99% of the sun's high frequency ultraviolet light, which is potentially damaging to life on earth. Over 91% of the ozone in Earth's atmosphere is present here. It is mainly located in the lower portion of the stratosphere from approximately 10 km to 50 km above Earth, though the thickness varies seasonally and geographically. The ozone layer was discovered in 1913 by the French physicists Charles Fabry and Henri Buisson.

The ozone layer in the stratosphere absorbs a portion of the radiation from the sun, preventing it from reaching the planet's surface. Most importantly, it absorbs the portion of UV light called UVB. UVB has been linked to many harmful effect, including skin cancers, cataracts, and harm to some crops and marine life.

Open Ended

What are some of the harmful effects of UV light?

​ Scientists have established records spanning several decades that detail normal ozone levels during natural cycles. Ozone concentrations in the atmosphere vary naturally with sunspots, seasons, and latitude. These processes are well understood and predictable. Each natural reduction in ozone levels has been followed by a recovery. Beginning in the 1970s, however, scientific evidence showed that the ozone shield was being depleted well beyond natural processes. Atmospheric concentrations of ozone vary naturally depending on temperature, weather, latitude and altitude, while substances ejected by natural events such as volcanic eruptions can also affect ozone levels. The "Dobson unit", a convenient measure of the total amount of ozone.

Open Ended

Name 5 natural events that can cause ozone depletion.

​ However, these natural phenomena could not explain the levels of depletion observed and scientific evidence revealed that certain man-made chemicals were the cause. These ozone-depleting substances were mostly introduced in the 1970s in a wide range of industrial and consumer applications, mainly refrigerators, air conditioners and fire extinguishers. When chlorine and bromine atoms come into contact with ozone in the stratosphere, they destroy ozone molecules. One chlorine atom can destroy over 100,000 ozone molecules before it is removed from the stratosphere. Ozone can be destroyed more quickly than it is naturally created. Some compounds release chlorine or bromine when they are exposed to intense UV light in the stratosphere. These compounds contribute to ozone depletion, and are called ozone-depleting substances and methyl bromide. Although ODS are emitted at the Earth’s surface, they are eventually carried into the stratosphere in a process that can take as long as two to five years.

Open Ended

Name three man-made items that are contributing to ozone depletion.

Multiple Select

Which two elements destroy ozone molecules?

• chlorine

• carbon

• bromine

• sodium

​Ozone measurements fluctuate from day to day, season to season and one year to the next. Ozone concentrations are normally higher in the spring and lowest in the fall. In spite of these fluctuations, scientists have determined, based on data collected since the 1950’s, which ozone levels were relatively stable until the late 1970’s. Observations of an Antarctic ozone "hole"[1] and atmospheric records indicating seasonal declines in global ozone levels provide strong evidence that global ozone depletion is occurring.

Multiple Choice

A hole in the Ozone Layer was discovered over

• The equator

• The Artic

• Antartica

• Greenland