Climate Change and Natural Forces: A Deep Dive

Introduction

• Common misconception: Climate change is natural, like Ice Ages or palm trees in Antarctica.
• Importance of understanding misconceptions and educating about human-caused climate change.
• Aim: Use misconceptions as teaching moments to expand understanding.

Natural Forces and Climate Change

• Earth’s climate historically influenced by natural forces.
• Climate scientists study these forces to understand human-caused climate change.
• Climate models factor in natural forces; only match reality when human impacts are included.
• Natural forces alone cannot explain the speed and scale of climate change since the Industrial Revolution.

How Earth's Climate Works

• Temperature: Measure of atomic movement or jiggliness, relating to kinetic energy.
• Energy on Earth begins with the Sun; energy absorbed and redistributed across Earth.
• Greenhouse Effect:
  • Absorbed sunlight is re-radiated by Earth, absorbed by greenhouse gases (GHGs).
  • GHGs like CO2 and methane trap heat, warming the atmosphere and Earth's surface.
  • Essential for life, but excess GHGs lead to more warming.

Energy Budget and Climate Forcing

• Earth’s energy budget: Balance of incoming solar energy and outgoing energy to space.
• Radiative Forcing: Measures changes in Earth's energy balance.
  • Negative forcing: Planet cools.
  • Positive forcing: Planet warms.

Natural Climate Influencers

1. Solar Variability:

   • Sun's brightness changes over time, influencing Earth’s climate slightly.
   • Recent observations show steadiness or dimming, not accounting for current warming.

2. Volcanic Activity:

   • Eruptions release ash and sulfur, reflecting sunlight and cooling Earth.
   • Also release CO2; however, current volcanic CO2 emissions are small.

3. Chemical Weathering:

   • Natural process balancing CO2; slow process, not accounting for recent warming.

4. Short-term Climate Cycles:

   • E.g., El Niño: Influence climate over short periods; inadequate to explain long-term warming.

5. Ocean Absorption:

   • Oceans absorb 91% of extra heat energy, moderating atmospheric warming.

6. Earth’s Orbital Changes:

   • Milankovitch cycles affect solar radiation distribution; cannot explain current rapid warming.

Conclusion: Human Impact on Climate Change

• Climate models include all known natural factors and human activities.
• Modern climate change largely driven by human activities, especially fossil fuel emissions.
• Natural forces cannot explain the extent of recent warming without including human impact.

Final Thoughts

• Acknowledge that while climate change has natural components, current change is largely human-driven.
• Importance of recognizing human capability to address and mitigate climate change impacts.
• Encouragement to stay informed and active in climate solutions.