climate change?

Climate Change Overview

  • Climate change is the last topic of discussion in this course.

  • Importance emphasized over other ecological topics like life tables and population growth models.

  • The lecture is concluded with evaluation time, which requires students to bring their computers instead of phones for ease of filling out a prompt.

Context and Definition

  • Quote referenced: "Human beings are now carrying out a large scale geophysical experiment of a kind that could not have happened in the past nor be reproduced in the future…." This indicates the uniqueness of current human impact on the Earth.

  • The emphasis is on understanding that we are conducting an unprecedented experiment regarding the atmosphere and oceans due to greenhouse gas concentrations.

Greenhouse Effect

  • Definition: The greenhouse effect occurs when solar radiation is trapped by the Earth's atmosphere.

  • This is a natural process essential for maintaining life on Earth, as it helps to warm the planet.

  • Discussion about common experiences such as the hot temperature inside a parked car.

  • Climate change is intensified by anthropogenic (human-induced) activities.

Protective Qualities of the Atmosphere

  • The atmosphere acts as a protective layer composed of gases that moderate temperatures and provide shielding from solar radiation.

  • The ozone layer, which is comprised of ozone (O3), protects from harmful ultraviolet (UV) radiation from the sun.

    • UV radiation can lead to health issues like skin cancer, particularly seen in areas like Australia where ozone depletion is observed.

Thermal Consequences of the Atmosphere

  • Solar radiation enters the atmosphere, loses energy upon striking Earth, and is converted to lower energy waves that cannot escape back through the atmosphere.

  • This entrapment raises ground level temperatures, similar to how heat is trapped in a car.

Gaseous Molecules Contributing to the Greenhouse Effect

  • Primary focus on carbon dioxide (CO2), which is a significant greenhouse gas.

  • Current concentration of CO2 is approximately 430 parts per million (ppm).

    • This is an increase from 405 ppm in 2017, indicating a worrying upward trend in atmospheric CO2.

Measurement and Location of Data

  • The Mauna Loa Observatory in Hawaii is cited as the location for accurate measurement of global CO2 concentrations due to its remoteness, reducing local pollution impact.

  • Graphical representation of CO2 levels over time shows a continuous rise, with seasonal fluctuations.

Carbon Dioxide and Other Greenhouse Gases

  • Importance of CO2 is highlighted due to its significant volume released into the atmosphere (81% of greenhouse gases from the U.S. emissions as of 2014).

  • Methane identified as a key greenhouse gas, particularly emitted from livestock digestion, landfills, and natural gas usage (cooking and heating households).

    • It has substantial global warming potential, with one molecule being equivalent to 21 molecules of carbon dioxide.

  • Nitrous oxide (NOx) and fluorinated gases, such as CFCs (Chlorofluorocarbons), are also discussed.

    • Fluorinated gases are man-made, extremely stable, and can cause significant ozone depletion and have a global warming potential thousands of times greater than CO2.

Global Warming Potential (GWP)

  • GWP is a metric that indicates the extent a gas can contribute to global warming compared to CO2.

  • CO2 as a benchmark:

    • Methane (21 CO2 equivalents)

    • Nitrous oxide (310 CO2 equivalents)

    • Hydrofluorocarbons (1000 CO2 equivalents)

  • Not all greenhouse gases impact climate equally, emphasizing a need for focus beyond just CO2 emissions.

Effects of Climate Change

  • Discussion encouraged on climate change effects among peers without looking at materials, leading to the identification of:

    • Habitat loss and species extinction

    • Ocean acidification

    • Increased natural disasters and extreme weather

    • Coral endangerment

    • Melting ice caps and glaciers leading to rising sea levels

    • Impact on food security due to extreme weather affecting crops

    • Increased prevalence of invasive species due to warmer temperatures

    • Altered ocean currents, which could lead to further ecological changes

Distinction Between Global Warming and Climate Change

  • Underline importance that “climate change” is the correct term, as it encompasses both warming temperatures and varied ecological effects, including extreme cold spells.

  • Misuse of “global warming” can lead to misconceptions about climate effect complexities.

Human Contribution to Greenhouse Gas Emissions

  • Many sources identified for emissions, including:

    • Industrial processes

    • Household chimneys

    • Deforestation which reduces carbon absorption capability of trees.

    • Farming contributes significantly to CO2 emissions.

Financial and Ethical Implications of Climate Change

  • Financial burden on society due to increasing extreme weather events, which amount to billions in disasters annually. Increased spending corresponds to disaster recovery, insurance, and infrastructure repair, affecting individual finances through taxes, specifically FEMA (Federal Emergency Management Agency) funding.

  • Potential for geopolitical conflicts arising from resource scarcity driven by climate changes, exemplified by drought-induced conflicts in Syria.

Conclusion and Call to Action

  • The increase in climate change-related disasters is immediate and alarming, requiring public awareness and actionable changes in policy and behavior.

  • Emphasis on how climate change is presently influencing both environment and economy, with special attention given to the immediate urgency of understanding and responding to this phenomenon.