## Nature’s Solution to Climate Change

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### Whales and carbon sequestration
- Each great whale sequesters 33 tons of CO2, on average, when it dies and sinks to the ocean floor, removing that carbon from the atmosphere for centuries.
- A tree absorbs only up to 48 pounds of CO2 a year.
- Whales accumulate biomass carbon during long lives; deadfall carbon from whale carcasses supports deep-sea ecosystems and is incorporated into marine sediments.

### The whale pump and phytoplankton multiplier effect
- Phytoplankton capture 37 billion metric tons of CO2, an estimated 40 percent of all CO2 produced.
- This phytoplankton CO2 capture is equivalent to the amount captured by 1.70 trillion trees—four Amazon forests’ worth—or 70 times the amount absorbed by all the trees in the US Redwood National and State Parks each year.
- Whales increase phytoplankton productivity by:
  - Bringing iron and nitrogen to the surface through vertical movement (“whale pump”).
  - Transporting nutrients across oceans through migration (“whale conveyor belt”).
- Even a 1 percent increase in phytoplankton productivity thanks to whale activity would capture hundreds of millions of tons of additional CO2 a year, equivalent to the sudden appearance of 2 billion mature trees.
- Phytoplankton contribute at least 50 percent of all oxygen to the atmosphere.

### Population recovery potential and impacts
- Prewhaling global numbers estimated at 4 to 5 million whales versus slightly more than 1.3 million today.
- Overall whale populations are now less than one-fourth what they once were.
- Some species, like the blue whales, have been reduced to only 3 percent of their previous abundance.
- If whales returned to prewhaling numbers and captured 1.7 billion tons of CO2 annually, it would have major climate benefits.
- Average whale lifespan is more than 60 years; population recovery timelines:
  - It would take over 30 years just to double the number of current whales.
  - It would take several generations to return them to their prewhaling numbers.

### Economic valuation and financing
- Conservative estimates place the value of the average great whale, based on carbon sequestration and other activities (fishery enhancement, ecotourism), at more than $2 million.
- The current stock of great whales is valued easily over $1 trillion.
- Whale watching industry estimated at over $2 billion globally.
- Fishing industry estimated at over $150 billion; whales contribute to the food web chain and increased fish stocks.
- Deforestation accounts for 17 percent of carbon emissions (as context for REDD).
- If whales captured 1.7 billion tons of CO2 annually, subsidizing their CO2 sequestration would be worth about $13 a person a year.

### Institutional arrangements and policy recommendations
- Whales produce international public goods; their benefits are global and nonrivalrous, creating a “tragedy of the commons” problem that requires global coordination.
- Proposed finance and governance mechanisms:
  - Adapt REDD-style international incentives to support whale population restoration (subsidies or compensation).
  - Compensate actors who incur costs from protection measures (for example, shipping companies for altered routes to reduce collisions).
  - Establish a funded financial facility to promote restoration and protection of whales and other natural assets.
- Roles for multilateral institutions:
  - Global Environment Facility: support low-income and fragile states in mitigation measures.
  - IMF: help governments integrate whale-related macroeconomic benefits and protection costs into macro-fiscal frameworks.
  - World Bank: design and implement programs to compensate private sector actors for whale protection.
  - Other UN and multilateral organizations: oversee compliance and collect data to measure progress.

### Threats to whales and priorities for protection
- Current life‑threatening hazards include ship strikes, entanglement in fishing nets, waterborne plastic waste, and noise pollution.
- Enhancing protection from these human-made dangers would deliver benefits to humans, the planet, and whales themselves.
- The “earth-tech” strategy—protecting and restoring whale populations—avoids risks associated with untested high-tech carbon-capture fixes.

### Key statistics (exact figures from the source)
- 33 tons of CO2 sequestered per whale (average, at death).
- Up to 48 pounds of CO2 absorbed per tree per year.
- Phytoplankton capture 37 billion metric tons of CO2 per year.
- Phytoplankton capture an estimated 40 percent of all CO2 produced.
- Equivalent capture to 1.70 trillion trees; 70 times the annual capture of trees in US Redwood National and State Parks.
- Current global whale population: slightly more than 1.3 million.
- Prewhaling estimated population: 4 to 5 million.
- Overall whale populations now less than one-fourth historic levels.
- Blue whales reduced to 3 percent of previous abundance.
- Even a 1 percent phytoplankton productivity increase would capture hundreds of millions of tons of additional CO2 a year, equivalent to 2 billion mature trees.
- Average whale lifespan: more than 60 years.
- Value of average great whale: more than $2 million.
- Value of current stock of great whales: easily over $1 trillion.
- Whale watching industry: over $2 billion globally.
- Fishing industry: over $150 billion.
- Deforestation: 17 percent of carbon emissions.
- Potential annual CO2 capture if whales return to prewhaling numbers: 1.7 billion tons of CO2.
- Estimated per-person subsidy worth: $13 a person a year.
- Time to double current whale numbers: over 30 years.

*Source: IMF Finance & Development, December 2019 (PDF chapter "Nature’s Solution to Climate Change" by Ralph Chami, Thomas Cosimano, Connel Fullenkamp, and Sena Oztosun).*

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_Source: https://www.imf.org/-/media/files/publications/fandd/article/2019/december/zh-do-not-use-rekia/natures-solution-to-climate-change-chami.pdf_