Chemistry in Context - Climate Change

Climate Change Overview

Chapter Overview

• Introduced by the American Chemical Society and McGraw Hill LLC.
• Focuses on climate change and its various aspects including greenhouse gases, carbon sources, and anthropogenic impacts.

Key Questions Addressed

1. What are the sources of carbon on Earth?
2. How much carbon dioxide is added to the atmosphere every year?
3. Importance of the greenhouse effect on Earth.
4. Characteristics of greenhouse gases.
5. Mechanism of greenhouse gases and instrumentation for measuring heat absorption.
6. Methods for reconstructing past climates and differences from current trends.
7. Evidence of the anthropogenic origins of the current climate crisis.
8. Factors affecting average global temperature.
9. Consequences of the modern climate crisis.
10. Strategies for lessening the impacts of climate change.

The Greenhouse Effect & Climate Change

Video Introduction

• A video is referenced to further elaborate on the greenhouse effect.

Questions to Consider

• What is the greenhouse effect and its impacts?
• Sources of carbon dioxide in the air?
• Definition and relationship of climate change to the greenhouse effect?
• Evidence supporting current climate change.

Home Experiment: Melting Glaciers and Icebergs

Materials Needed

• 2 ice cubes, a large flat rock, 2 rulers, tape, a marker, water, 2 clear glasses.

Experiment Procedure

1. Tape a ruler to each glass, making sure it touches the table.
2. Place the rock in one glass, add water until the top of the rock is above water and mark this level.
3. Pour the same amount into the second glass, marking this level.
4. Add an ice cube to each glass, positioning the ice cube on the rock in the first glass.
5. Observe the changes in water levels after 30 minutes and one hour.

Questions to Consider

• Which glass simulates a glacier vs an iceberg?
• Changes in water levels in each glass relate back to climate change impacts on glaciers and sea levels.

Impacts of Climate Change

Projections by IPCC

• An intermediate projection by the IPCC (2021) predicts a temperature increase of 2.7 °C (4.9 °F) above pre-industrial levels by 2100.
• High-tide threats to over 800 million people, or 12% of the global population.

Visuals

• Figure illustrating sea-level rise scenarios at 1.5 °C and 3 °C warming (Lalbagh Fort example).

Carbon Cycle and Sources

Learning Objectives

• Illustrate carbon reservoirs and understand carbon movement.
• Identify and quantify human-induced CO2 emissions.

Carbon Definition and Examples

• Organic chemistry connects to carbon-based compounds.
• Elemental carbon forms include diamond and graphite.
• Notable carbon compounds:
    - Table sugar: $C_{12}H_{22}O_{11}$
    - Methane: $CH_{4}$
    - Acetone: $C_{3}H_{6}O$
    - Carbon dioxide: $CO_{2}$

Global Carbon Cycle

Main Reservoirs of Carbon

1. Atmosphere: CO2 (400 ppm), methane (1.8 ppm), carbon monoxide (trace amounts).
2. Carbonate rocks, fossil fuels, and soils.
3. Biological matter: plants and animals.
4. Water bodies: dissolved CO2 in oceans and surface waters.

Carbon Accumulation

• Carbon accumulation in the atmosphere is quantified in petagrams (Pg).
    - Definition: 1 Pg = 1 Gt of carbon = 1 billion metric tons, roughly 2.2 trillion pounds.

Understanding the Carbon Cycle

Your Turn - Carbon Cycle Exercise

Questions

• Processes that add or remove CO2 in the atmosphere?
• Identification of the two largest carbon reservoirs?
• Role of human activities in the carbon cycle?
• Explanation for the term “carbon cycle.”

Visualizing the Carbon Cycle

• Observations of photosynthesis and respiration cycles affecting CO2 concentration seasonally.

Carbon Dioxide Emissions

Sources

• Major contributors are fuel burning for electricity, transport, heating, and industrial processes.
• Fugitive emissions refer to accidental methane leakage from fossil fuel extraction.

Quantifying Carbon Dioxide and Atomic Mass

Learning Objectives

• Understand isotopes and derive relative atomic masses.
• Apply Avogadro's number for quantifying atomic and molecular masses.

Concept Definitions

• Isotopes: Atoms with the same protons, but different neutrons.
• Relative Atomic Mass: Weighted average of isotopes.

Example Isotope Data

Average Atomic Mass Calculation

• $ext{Average atomic mass of C} = 11.868 + 0.143 + 0.0001 = 12.011$

Your Turn – Isotopes of Nitrogen

Questions

• Determine the atomic structure for N-14 and N-15?
• Comparison of isotopes in terms of abundance and mass.

Avogadro's Number and Mole Concept

Definitions

• Mole: Amount of substance containing elementary entities (atoms, molecules) equal to Avogadro's number.
• Molar Mass: Mass of one mole of a substance.
• Example Calculations: Mass differences between chicken and ostrich eggs.

Human Impact on Climate

Current Trends

• Temperature rise due to greenhouse gas emissions.
• Importance of recognizing human impact on climate change.

Climate Change Mitigation

Strategies

• Implementation of policies for reducing carbon emissions: carbon tax and cap-and-trade systems.

Examples

• Carbon tax implementation in Sweden.
• Cap-and-trade mechanisms in California.

Ecological Footprint

Overview

• Global biocapacity deficits illustrate consumption exceeding renewable resources.

Conclusion

Impacts of Climate Change

• The IPCC stresses the urgency of action to combat climate change and its threats to ecosystems and human life.

Urgent Call to Action

• Countries to commit to substantial reductions in emissions and collaborative efforts to maintain planetary health.