Understanding Global Climate Change

• The Intergovernmental Panel on Climate Change (IPCC), a UN body, released a report on global climate change, with important conclusions.
• World climate change has significantly changed over the past century due to human influence.
• Using climate change models, the global mean surface temperature will increase between 1 degree Celsius and 3.5 degrees Celsius by 2100 if the current trend continues.
• Global climate change could alter life on the planet more than anything except nuclear war.
• Climate change is distinct from constantly changing weather patterns.
• Climate change refers to long-term weather patterns over a given area.
• The term "climate" originates from the Greek word "klinein," which means slope.
• Climate change is defined as statistically significant climate changes over a continuous time period.
• Factors that contribute to climate change include natural internal processes, external forces, and persistent anthropogenic changes.
• Changes also occur via alterations in the composition of the atmosphere or in land use, and through natural occurrences or human actions.
• Causes of climate change are both natural and due to human activities.

Natural Causes of Climate Change

• Volcanic eruptions emit natural aerosols like carbon dioxide, sulfur dioxide, salt crystals, volcanic ash, dust, and even microorganisms.
• Aerosols emitted from volcanic eruptions can block solar radiation, leading to a cooling effect that can last for one to two years.
• Changes in Earth's orbit can cause climate change, explained by the Milankovitch theory.
• The Milankovitch theory states cyclical variations in Earth-Sun geometry affect the amount of solar energy reaching Earth.
• The three elements that have cyclic variations are eccentricity, obliquity and precession.
• Eccentricity is the shape of the Earth's orbit around the Sun influencing seasonal differences, with closer proximity to the sun resulting in more solar radiation.
• Obliquity is the variation of the tilt of the Earth's axis that exaggerates the seasons.
• Precession is the change in the orientation of Earth's rotational axis, with a cycle of 19,000 to 23,000 years, caused by the Earth's wobble and orbit.
• Carbon dioxide is added when power and heat is produced by burning coal, oil, and other fossil fuels.
• Carbon dioxide is transparent to sunshine but absorbs and returns infrared radiation, warming the air near the surface.

Human Activities that contribute to Climate Change

• Burning of fossil fuels contributes to climate change.
• Greenhouse gases and aerosols contribute to climate change.
• Deforestation contributes to climate change.
• Air pollution contributes to climate change.

Effects of climate change in the society

• Climate change could severely affect all life forms on the planet.
• Climate change affects basic elements of people's lives.
• Climate change increases worldwide deaths from malnutrition and heat stress.
• Climate change results in melting glaciers and rises in sea level.
• Ecosystem are particularly vulnerable to climate change.

Elements in the interaction between the Sun and Earth

• Aphelion is the point in Earth's orbit farthest from the Sun.
• Perihelion is the point in Earth's orbit closest to the Sun.
• Earth's axial tilt is the inclination angle of Earth's rotational axis.
• Precession is the change in the orientation of the rotational axis of the Earth.
• Equinox happens when the sun at noon is directly over the equator, which happens twice a year and causes almost equal length of day and night.
• Solstice happens when the noon sun sits above the Tropic of Cancer or Capricorn, where the summer solstice has the longest daylight period, and the winter solstice has the shortest daylight period.
• Precession of the equinoxes refers to the motion of the equinoxes relative to the precession of Earth's axis of rotation which happens over thousands of years.

Milankovitch Parameters

• In the 1930s, Milutin Milankovitch addressed the causes of dramatic changes in daily weather and climate.
• He discovered the distance between the Sun and the Earth is not constant.
• Contemporary scientists critiqued his work.
• Milankovitch parameters include changes in Earth's orbit, tilt, and wobble.

Global warming

• Over 90% of scientists who study Earth's atmosphere indicate temperatures have been rising since the latter part of the 20th century.
• There are opposing views on whether global warming is natural or not.
• One side thinks that nature, is the main reason with no reference to human actions.
• The other side states that global warming is caused or greatly abutted by the actions of human beings.

Greenhouse Gases

• Greenhouse gases trap the sun's heat in the atmosphere.
• John Tyndall, a British engineer, said that certain gases in the atmosphere naturally capture and hold heat which causes Earth's temperatures to be higher.
• According to Tyndall, water vapor is the most prevalent greenhouse gas.

Future Actions

• One debate centers on predictions for the world's climate.
• Computer models setting "tipping points" are used to specify changes.
• Reaching "tipping points" will replace the old state with a new one.
• Chaos theory suggests Earth's atmosphere could become chaotic.
• Burning fossil fuels is a major source of electricity, but it also leads to higher carbon dioxide levels.
• Balancing industrialization with environmental protection requires a balanced plan.
• Science allows the emergence of technology that spreads and applies knowledge for the attainment of the good life.
• Science is a process of experimentation, innovation, and refinement

Mitigation Strategies

• Plant trees.
• Be responsible.
• Green the land.
• Freshen the air
• Reduce use of aerosols.
• Avoid illegal logging.
• Minimize burning plastics and fossil fuels.
• Reduce smoke emission.
• Use less transportation.