⚡ Energy & Climate

What you’ll learn

1. Energy Is CivilizationEstablish energy as the master resource and frame the fossil-fuel bargain.Abundant energy underwrites modern life and correlates with longer, wealthier lives; fossil fuels still supply about four-fifths of it because they are dense, storable, and long cheap. They are concentrated ancient sunlight stored as carbon, so releasing their energy means burning carbon and producing CO₂ — the bargain the rest of the course examines.
2. The Carbon ConnectionExplain the combustion-to-CO₂ chemistry and the greenhouse mechanism.Burning hydrocarbons combines carbon with oxygen to make CO₂. CO₂ is transparent to incoming sunlight but absorbs outgoing infrared, re-radiating some back — like a blanket. The natural greenhouse effect keeps Earth livable (else ~−18 °C); the problem is thickening the blanket by adding fossil carbon, which raises the equilibrium temperature, with a lag from ocean heat capacity.
3. Reading the EvidenceShow how CO₂ is measured and place the modern rise in deep-time context.Continuous CO₂ measurement at Mauna Loa since 1958 (the Keeling Curve) shows a relentless climb. NOAA reports the 2024 global average near 422.8 ppm, about 50% above the pre-industrial ~280 ppm, with 2024's rise the largest on record. Ice cores directly measure ancient trapped air, showing CO₂ stayed between ~180–300 ppm for 800,000 years — today's level is off that dial.
4. What Warming Actually DoesReframe global temperature as accumulated energy and derive the consequences.A ~1.2 °C average rise sounds trivial but measures a large energy imbalance, most of it stored in the oceans. That energy raises seas (expansion and melt), adds about 7% atmospheric moisture per °C (heavier downpours, deeper droughts), fuels stronger storms, and shifts rare extremes into common ones — without daily weather needing to feel dramatically different.
5. Where Our Power Comes FromRead the current global electricity mix and identify coal as the incumbent.In 2023 (Ember), fossil fuels produced about 61% of global electricity with coal the single largest source; renewables reached 30% for the first time and clean sources including nuclear about 39%. Coal is cheap, abundant, and dispatchable but the most carbon-intensive fuel — the core tension of the transition between reliable-and-cheap and clean.
6. The Clean Options and Their Real CostsCompare lifecycle emissions of sources and examine nuclear's genuine trade-offs.Lifecycle emissions count all CO₂ from manufacture to decommissioning. IPCC AR5 medians: coal ~820, gas ~490, solar ~48, hydro ~24, nuclear ~12, onshore wind ~11 gCO₂eq/kWh — low-carbon sources roughly an order of magnitude below fossil. But 'clean' is multidimensional: nuclear is ultra-low-carbon and dispatchable yet raises waste, cost, and accident concerns on which informed people disagree.
7. The Systems ProblemExplain intermittency and why bridging the gaps is the hard part.Grids must match supply to demand every second. Dispatchable sources generate on command; variable renewables (wind, solar) follow the weather, so you can't simply swap capacity for capacity. Bridging the gaps needs storage (batteries, pumped hydro), bigger grids, flexible demand, or reserve capacity. The first renewables are cheap; squeezing out the last fossil plants that cover dark, windless periods is the costly frontier.
8. The Transition AheadPlace today's shift in the history of energy transitions and state the honest picture.Humanity has changed primary energy base before — muscle/wood to coal to oil — usually because the new source served needs better. Today's shift is driven partly by avoiding carbon, but solar and wind are now often the cheapest new power, giving it momentum beyond policy. The physics of the problem is settled and un-exaggerated; the solutions are partial, improving, and genuinely contested on pace and cost.

Questions this course answers

Grounded in trusted sources

• NOAA Global Monitoring Laboratory, Trends in Atmospheric Carbon Dioxide (gml.noaa.gov/ccgg/trends)
• NOAA news release, 'Carbon dioxide levels surge faster than ever' (2025)
• Ember, Global Electricity Review 2024 (2023 generation data)
• IPCC Fifth Assessment Report (AR5), WG3 Annex III — lifecycle greenhouse-gas emissions of energy sources
• Wikipedia, 'Life-cycle greenhouse-gas emissions of energy sources' (IPCC AR5 median values)
• IPCC Sixth Assessment Report (AR6) synthesis
• Vaclav Smil, 'Energy and Civilization: A History'

Every Wunder lesson is built from real, reputable sources — never invented.

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