Whale Carbon Calculator

Whales sequester carbon through two main pathways. First, via <strong>whale falls</strong>: when a whale dies, its enormous carbon-rich body sinks to the seafloor, locking that carbon away from the atmosphere for centuries. Second, via the <strong>whale pump</strong>: whales feed at depth and defecate at the surface, recycling nutrients like iron and nitrogen that fertilise phytoplankton, which then photosynthesise and absorb CO₂.

A whale fall occurs when a deceased whale sinks to the deep ocean floor. Because whales are large and carbon-dense (roughly 15–17% of body mass is carbon), each whale fall deposits significant organic carbon into deep sediments where it can be stored for hundreds to thousands of years. This is considered the more certain of the two whale carbon sequestration pathways.

The whale pump concept is scientifically plausible — whale faeces are rich in iron and nitrogen, which can stimulate phytoplankton blooms in nutrient-poor waters. However, research by Hannah Ritchie and others suggests the overall climate benefit of the whale pump may be considerably smaller than popular estimates imply, with significant uncertainty in the numbers. It's a real effect, but should not be the primary justification for whale conservation.

This varies by species and individual size, but as a rough guide: a large blue whale (averaging ~100 tonnes) stores around 15–17 tonnes of carbon in its body, equivalent to roughly 55–62 tonnes of CO₂. A humpback whale averaging ~30 tonnes stores approximately 4–5 tonnes of carbon. These figures inform the whale fall component of this calculator.

Most scientists and conservationists caution against framing whale protection primarily as a climate solution. The carbon sequestration values, while real, are relatively modest compared to other interventions like protecting forests. Whales have immense ecological, biodiversity, and intrinsic value that are far stronger arguments for their conservation than the carbon numbers alone.

Carbon prices vary widely depending on the market. Voluntary carbon markets have ranged from roughly $3 to $200+ per tonne CO₂. Compliance markets like the EU ETS trade around $60–$90 per tonne as of 2024. Social cost of carbon estimates used in policy analysis often range from $50 to $200 per tonne. A mid-range value of $50/tonne is a reasonable default for illustrative purposes.

Larger species sequester more carbon per individual simply due to body mass — blue whales are the most carbon-rich animals on Earth. However, population size matters enormously: a healthy, numerous population of smaller minke whales may collectively sequester more carbon annually than a critically small population of blue whales. This calculator lets you adjust species and population size to explore both factors.

Industrial whaling in the 20th century reduced some whale populations by 66–90% from their pre-whaling levels. This represented an enormous loss of natural carbon storage capacity. Estimates suggest the removal of great whales may have released tens of millions of tonnes of stored carbon and reduced the ongoing sequestration potential of the ocean. Rebuilding whale populations is one way to partially restore this natural carbon sink.