Hoja de repaso: GEOPO S1

Energy and Environmental Dynamics Revision Sheet

1. 📌 Essentials

• Energy is the capacity to perform work enabling physical and societal transformations.
• The conservation of energy states energy cannot be created or destroyed, only transformed.
• Fossil fuels comprise approximately 77% of current global energy consumption (2023).
• Human population has grown from 1 billion in 1850 to over 8 billion today, driving energy demand.
• CO₂ emissions are directly linked to energy use, contributing to climate change.
• Limiting global warming to 2°C requires capping total CO₂ emissions around 3,000 billion tons.
• Planetary Boundaries define Earth's safe operating space; many are exceeded, risking irreversible change.
• Biodiversity is threatened by habitat destruction, pollution, invasive species, and climate change.
• Ecosystems currently act as carbon sinks but may become sources due to degradation.
• Unchecked biodiversity loss and environmental degradation threaten ecosystem services essential for life.

2. 🧩 Key Structures & Components

• Fossil Fuels (oil, coal, natural gas) — main energy sources, rich in energy density, easy to access and use.
• Energy Converters — machines (engines, turbines) and biological systems (humans, animals) that transform energy forms.
• Carbon Cycle Components — biosphere, atmosphere, ocean, complexes of ecosystems acting as carbon sinks or sources.
• Planetary Boundaries Framework — nine global limits (climate change, biodiversity, nitrogen cycle, etc.).
• Ecosystems — habitats like forests, oceans, and wetlands providing climate regulation, biodiversity, and resource flow.
• Invasive Species & Pollution — biological and chemical disturbances disrupting native ecosystems.

3. 🔬 Functions, Mechanisms & Relationships

• Energy flow hierarchically from primary sources (fossil, renewable) to end-use (transport, heating, industry).
• Fossil fuel extraction increases CO₂ in the atmosphere, elevating greenhouse gas concentrations.
• Global energy demand correlates with population growth; higher demand fuels more emissions.
• Climate change is caused by excess greenhouse gases trapping infrared radiation, warming the planet.
• Biodiversity loss reduces ecosystem resilience, impairing carbon sequestration and other functions.
• Planetary boundaries are interconnected; crossing one risk cascade effects on others (e.g., climate and biodiversity).
• Mitigation measures include ecosystem restoration, reducing fossil fuel dependency, and sustainable land use.
• Environmental degradation reverts ecosystems from sinks to sources, exacerbating climate warming.

4. Comparative Table

Item	Key Features	Notes / Differences
Fossil Fuels	Main energy source; high energy density, emitted CO₂	Oil, coal, natural gas; finite reserves
Renewables	Low or zero emissions; variable intermittency	Solar, wind, hydro, bioenergy
Carbon Intensity (gCO₂/kWh)	Ranges from 6 (nuclear) to 1058 (coal)	Indicates emissions per energy unit
Planetary Boundaries	9 critical Earth system limits; many exceeded	Climate, biodiversity, biogeochemical flows

5. 🗂️ Hierarchical Diagram

Global Energy System
 ├─ Primary Sources
 │    ├─ Fossil Fuels
 │    └─ Renewables
 ├─ Conversion & Use
 │    ├─ Machines & Engines
 │    └─ Biological Systems
 └─ Environmental Impact
      ├─ Climate Change
      ├─ Biodiversity Loss
      ├─ Ecosystem Degradation
      └─ Pollution & Invasive Species

6. ⚠️ High-Yield Pitfalls & Confusions

• Confusing energy "costs" with actual energy content; units matter.
• Overestimating ecosystems' capacity as permanent carbon sinks; current trend shows risk of reversal.
• Misunderstanding the difference between power (W) and energy (Wh).
• Assuming all renewable energy is sustainable without considering ecological impacts.
• Underestimating the rapid acceleration of biodiversity loss and its ecosystem implications.
• Believing monocultures or bioenergy plantations are viable long-term solutions.
• Ignoring the interconnectedness of planetary boundaries when proposing mitigation strategies.
• Overgeneralizing "lungs of the planet" (e.g., Amazon) as always a carbon sink—they are increasingly a source.

7. ✅ Final Exam Checklist

• Define energy and explain its role in societal transformations.
• State the conservation of energy law and its implications.
• List the main fossil fuels and their contribution to current energy consumption.
• Explain the relationship between energy use and CO₂ emissions.
• Describe the planetary boundaries concept and which ones are exceeded.
• Identify major environmental threats: habitat loss, pollution, invasive species.
• Discuss how ecosystems act as carbon sinks and current threats.
• Recognize the scale of human energy consumption relative to biological systems (e.g., "energy slaves").
• Outline strategies for sustainable energy use and ecosystem restoration.
• Understand the significance of the climate-energy link and global warming limits.
• Be aware of the main challenges posed by biodiversity and ecosystem degradation.
• Differentiate between false solutions (monocultures, greenwashing) and genuine sustainability actions.
• Know the current status of resource reserves and implications for future energy supply.
• Comprehend the interconnectedness of environmental systems and risks of crossing thresholds.

This revision sheet consolidates core facts, structures, relationships, and cautionary points to prepare effectively for exams on energy and environmental dynamics.