Recently, an increasing number of scientists have argued that animals such as whales could actively contribute to the removal of carbon from the atmosphere and thus help mitigate climate change.
However, by reviewing the main ways in which baleen whales (such as humpback whales) remove atmospheric carbon at both regional and global scales, a team of researchers led by Griffith University in Australia has recently found that the amount of potential carbon capture by whales is unfortunately too little to significantly alter the trajectory of climate change.
“Our study supports that whales are important for the marine ecosystem, but their contribution to the global carbon flux is too small to effectively reduce atmospheric carbon. While our research group would very much like to highlight the opposite in order to benefit the conservation of whales and perhaps one day use carbon credits to support research, the debate is misguiding and creates false hope,” said lead author Jan-Olaf Meynecke, a research fellow in Behavioral Ecology at Griffith.
“This is in contrast to media perpetuating whales as climate engineers. Creating false hope in the ability of charismatic species to be climate engineers may act to further delay the urgent behavioral change needed to avert catastrophic climate change impacts, which can in turn have indirect consequences for the recovery of whale populations.”
The ocean carbon cycle is a crucial factor driving global climate, and clarifying how whales and other animals potentially contribute to it is highly important for climate mitigation efforts. According to some scientists, whales can contribute to carbon capture through their biomass in which carbon can be kept for decades (depending on their lifespan), and even after their death, if they sink to the ocean floor and are covered by sediment.
However, as the authors of the current study stress, overstating whales’ ability to prevent or counterbalance anthropogenic changes in global carbon budgets could unintentionally redirect attention from well-established – and highly needed – methods for reducing greenhouse gas emissions.
“Previous estimations neglect the scale in which carbon sequestration occurred both temporally and spatially. Some of the pathways suggested for carbon sequestration such as whale falls (when whales die and sink to the ocean floor but retain carbon for decades) also underestimate the breathing of whales,” Meynecke explained.
“We think it is important to acknowledge that there are other values of whales that are more relevant to drive their conservation than carbon capture. Large scale protection of marine environments including the habitats of whales will build resilience and assist with natural carbon capture at a global scale,” he concluded.
The study is published in the journal Frontiers in Marine Science.
Carbon capture, also known as carbon capture and storage (CCS), is a process designed to mitigate greenhouse gas emissions and combat climate change. This technology aims to capture carbon dioxide (CO2) emissions produced from the use of fossil fuels in electricity generation and industrial processes, preventing the CO2 from entering the atmosphere. The captured CO2 is then stored underground in geological formations.
The capture stage involves the separation of CO2 from other gases produced in electricity generation and industrial processes. There are three primary techniques used for this:
This involves capturing CO2 after fossil fuels have been burned and the resultant gases have been cleaned. This is the most widely used method as it can be retrofitted to existing power and industrial plants.
In this process, fossil fuels are partially oxidized to produce a mixture of carbon monoxide and hydrogen. The carbon monoxide is then reacted with water to produce CO2, which can be captured. The remaining hydrogen can be used as a low-carbon fuel.
Here, fossil fuels are burned in oxygen rather than air. As a result, the flue gas is primarily CO2 and water vapor, which can be easily separated to capture CO2.
After the CO2 is captured, it must be transported to a storage site. This is usually done through pipelines that have been specifically constructed for this purpose. In certain situations where pipelines are impractical, other methods like shipping might be used.
The final stage involves storing the captured CO2. This is typically done by injecting the CO2 deep underground into geological formations. These can include depleted oil and gas fields, unminable coal seams, or deep saline aquifers.
While carbon capture is seen as a potential solution to reduce greenhouse gas emissions, it also faces several challenges. These include high cost, energy required for the process, and the need for safe and long-term storage solutions. The technology also doesn’t address the emissions from the extraction and transport of fossil fuels. Furthermore, some argue that investment in CCS might detract from efforts to further renewable energy sources.
However, newer technologies are also being developed, such as Direct Air Capture (DAC), which involves removing CO2 directly from the atmosphere, and Bio-Energy with Carbon Capture and Storage (BECCS), which combines biomass use with CCS.