Summary of Global Climate Related Facts

§3.2: Annual Atmosphere Change

• Human Emissions: +38 GtCO₂.
• First-Year Natural Atmospheric CO₂ Removal: ≈20 GtCO₂.
  (Total removal: 100s-1000s of years.)
• Extra Human-Caused Atmospheric: +18 GtCO₂/year ≈ +2.5 ppm/year.
• 1870: 2,200 GtCO₂ ≈280ppm.
• 2021: 3,200 GtCO₂ ≈420ppm.

Not Yet In Book

§4.4.4. Atmosphere State

• Long-Run: 2 × CO₂ (ppm) ⇒ +1.0 C. Includes water vapor.
• ⇒ 50% increase from 280-420 ppm (+50%): ≈ 0.5 ° C

Data Basis: mostly IPCC 2021 6th Report (sometimes 5th) for RCP 4.5 and 7.0. RCP 6.0 is now interpolated.

§5.2: Expected (Economic) Damages

• The IPCC expects a global climate temperature change from 2025 to 2100 of about 2°C. The preventable temperature change is about 0.5°C.
• A 2°C change is equivalent to a move from
  
  • Boston to NYC to DC to Atlanta; or
  • Stockholm to Berlin to Milan to Rome to Palermo; or
  • Beijing to Tokio to Shanghai to Wenzhou to Fujian Xiamen to Hong Kong.
  (An 0.5°C difference is about the same as between Queens and the Bronx.)
• Terrestrial effects are difficult to assess: hotter but wetter. Uneven.
• More energetic weather phenomena.
• Sea level effects: 400 million displaced, primarily in Bangladesh and Indonesia.
• Significant net harm in poor, hot, and populous regions. Little net harm (but great changes) in rich, cool, and unpopulated regions.

§5.6: Dangers

• Fast speed of increase.
• Dormant feedback loops.
• Tipping points.
• The expected global temperature change could be about 4°C. It will almost surely be more in some locations.
• (Very rare asteroids, supervolcanos)

§6.3 Social Cost of CO₂ (SCC)

• Slight commmon misnomer: SCC is not the social cost of carbon, but of CO₂.
• SCC is globally optimal tax on CO₂:
  • more ⇒ curtail too much.
  • less ⇒ pollute too much.
• CO₂ sequestration cost is one ceiling to SCC.
• Many problems in real life: judging harm, inefficient administration, corrupt administration, differential harm, domicile escape.

§6.5.5: Marginal Thinking and Cost/Benefit

• COP are not about eliminating global warming but about reducing it by “10–20%.”
  • Consider RCP 6 to RCP 4.
  • Reduction of global warming by 2050 by 5% (from about 1.7°C to about 1.6°C).
  • Reduction of global warming by 2100 by 20% (from about 3°C to about 2.6°C).
• Est. required reduction: ≈ 15 GtCO₂/year.
• 4–5 GtCO₂ for each 0.1°C reduction by 2100.
• All US CO₂ emissions: 4.7 GtCO₂.
• 15 GtCO₂ at $50/tCO₂ about $750 billion:
  • About 1% of World GDP. About $100 per person per year.
  • About 1.5% of OECD GDP. About $500 per OECD inhabitant.
  • About 3.5% of US GDP. About $2,000 per US resident.
  • About size of US military spending.
  • About size of US Public School education spending.
• $50 SCC is reducible through (a) smart ramping up of CO₂ tax; (b) smart delay (better tech).

(Warning: All above numbers are immensely huge.)

§6.3: Cost Concepts

• Diminishing Returns;
• Sunk Costs;
• Learning Curves (FOAK);
• Returns to Scale;
• Optimal Delay.

§7.4: Key IAMS Issues

• sensitivity to discount rate.
• estimating future parameters.
• uncertainty and risk.
• omitted choices: population, income inequality, opportunity costs of other philanthropic activities.

Irrelevant

• Problem is understanding choices by decision-makers.
• World outcome is not the engineered solution to a world problem.
• OECD countries are no longer big enough to solve the problem.
• Non-OECD countries are too poor to fight it.

Key Problems

• §9.2: Global (SCC) carbon tax is impossible without a global government.
• §9.3: Treaties not in self-interest. Excludability and free-riding incentives. No similar treaty ever effective.
• §6: Carbon footprints known for decades. (Carbon-shaming or setting an example?)
• What will change? Need to convince 8–11 billion people, not just 25% of the (more climate-conscious) population in the 25% that the OECD represents.

Best Viable Choices

• §10.1: Adaptation.
• §10.2: Locally justifiable fossil-fuel taxes (PM Health costs: $10/tCO₂ to $100/tCO₂).
• §10.3: Clean Technology.
• §10.4: Reforestation with lumber harvesting.

§11.2: Fossil Fuels

• Achilles Heel: High mining and transport costs;
• 75% of fossil-fuel primary energy ends up as waste heat.
• Primary energy vs. Nameplate Power.
• PM Health costs: $10/tCO₂ to $100/tCO₂.

Fossil Fuel Alternatives

• §11.3: Hydrogen: similar to NatGas, but likely far too expensive for many decades.
• §11.4: Nuclear Power: • 1 Meltdown / 3,704 reactor years; • 500 (old) nuclear power plants worldwide; • waste disposal solution; • need safer reactors (pebble-bed?)
• §11.5: (Li) Batteries • <1/10 energy density of fossil fuels, but reusable; • High power, Low capacity; • Almost perfectly in/out-efficient; • Tiny capacity on grid (≈ 10 min total); • Expensive.

§11.7: Propaganda Clarifications

• Most clean-tech in lab will fail (true), but there are dozens of exciting techs in lab.
• All numbers are immensely large — think 1/10 of all agriculture.
• Space and materials needed for clean tech, but plenty are available long-run.
• Clean-tech enjoys some subsidies, though small compared to fossil fuels.
• Expect bumps on the road.

§12.3: Fundamentals.

• High-quality energy. Jack of all trades. High conversion efficiency to kinetic energy.
• Typical daily electricity demand pattern today: Low at noon; Peaks at 7am and 8pm.
• Typical clean-energy supply: High at noon, low at 7am and 8pm.

§12.7: Transmission

• About $2 million per GW per mile.
• Cheap now only because generation is near use. Will become more expensive as generation has to be farther away.
• Giant regulatory mess.

Key Points

• §14.1: Removal cost is one upper ceiling to the Social Cost of Carbon Dioxide.
• §14.2: Reforestation with lumber harvesting is cheapest method, perhaps as low as $10/tCO₂ for first marginal GtCO₂ (that world is not taking).
• Industrial CO₂ removal projects seem hopelessly expensive for decades to come. Economics work only to arbitrage government subsidies.
• §14.3: Solar radiation management is worth investigating, but not (yet) deploying. Danger of unintended consequences.

Favorites

• Increase innovation.
• Share technology better.
• Tax fossil fuels for local health.
• Forestation.
• Price by supply cost (time).
• Uproot bad habits / nudges.
• Reverse tech lock-in.
• Coordinate transition.
• Reduce green red tape.
• Targeted Federal land leases.
• Kill worst emitters.
• Minor international agreements.