Global Environmental Challenges: Climate Change, Pollution, and Ozone Depletion

Defining Environmental Impact and Hazard

Environmental Impact: Alterations or modifications of some magnitude that provoke a change in the environment or some of its components, produced directly or indirectly by living beings. The main originator of environmental impact is human activity.

Environmental Hazard: The possibility of producing damage of an irreparable nature.

Types of Environmental Hazards

Environmental hazards can be categorized as follows:

• Natural Hazards: Characterized by geological events (e.g., earthquakes and volcanoes) and weather events (e.g., storms and droughts).
• Anthropogenic Hazards: Induced by human action, including contamination and forest fires.

Global Climate Change and the Greenhouse Effect

Climate Change is the alteration of the global climate on Earth, characterized by:

• Increased temperatures.
• Variations in winds and strong precipitation.
• Changes in the frequency of various meteorological processes.

The Greenhouse Effect

This effect is produced by atmospheric gases (mainly CO2) that prevent part of the infrared radiation from the Earth's surface from diffusing into outer space. This causes an increase in surface temperature. The release of greenhouse gases due to human activity significantly increases global temperatures.

Primary Causes of Climate Change: CO2 Emissions

The major cause of climate change is the increase in CO2 emissions, primarily from general combustion processes.

Natural Sources of CO2:

• Respiration (expelling CO2).
• Decomposition of organic material by microorganisms.
• Natural forest fires.
• Volcanic eruptions.

Anthropogenic Sources of CO2:

• Fossil fuel combustion.
• Deforestation (cutting and burning trees).

Major Effects of Global Climate Change

• Rising sea levels.
• Decrease in precipitation.
• Increase in tropical diseases.
• Extinction of species and zones.
• Decrease in corals and reduction of biodiversity.
• Pollution and warming of the oceans.

International Protocols Against Climate Change

Key international efforts to combat climate change include:

• 1995: United Nations Framework Convention on Climate Change (UNFCCC).
• 1997: Kyoto Protocol, aimed at reducing CO2 emissions.

Atmospheric Pollution and Human Impact

Atmospheric Pollution is the presence of substances in the air that, above a certain limit, can cause direct or indirect harmful effects on materials and living beings. The human being is the largest polluter.

Ozone Layer Depletion and CFCs

Ozonosphere: A layer located between 20 and 40 km altitude, containing significant concentrations of ozone (O3).

Ozone is toxic if present in high concentrations in the troposphere, but in the stratosphere, it efficiently absorbs ultraviolet (UV) radiation.

CFCs (Chlorofluorocarbons): These are molecules containing chlorine, fluorine, and carbon. Industrially, they have been utilized as refrigerants, solvents, plastics, and aerosols.

CFCs are major destroyers of O3: In the upper atmosphere, CFC molecules decompose into highly reactive radicals. The release of these radicals provokes cyclic destruction reactions of O3.

Consequences of Ozone Layer Thinning

• Decrease in the ozone layer in the stratosphere.
• Increase in UV radiation reaching the Earth's surface.
• Alteration in the genetic material of living beings.