The skyrocketing emission of greenhouse gases has been leading to global warming and climate change. Scientists, across the globe, have been relentlessly trying to figure out innovative solutions to curb the concentration of carbon dioxide — a heat-trapping greenhouse gas — from the atmosphere. A glimmer of hope has emanated from the deep waters of our oceans in the form of whales! Yes, the behemoth creatures who have been ruling the water world for ages. When it comes to choosing between planting more trees and conserving more whales to sequester carbon from the atmosphere, we might benefit more from the latter. In recent years, policymakers have prioritised their preservation and conservation which has become a top climate agenda.
Whales are the natural carbon sink of our planet. Studies estimate that a single whale can absorb an average of 33 tonnes of carbon dioxide in its lifetime which is far better than the carbon sequestering capacity of a tree which absorbs 48 pounds of carbon dioxide per year — equivalent to 2.4 tonnes of CO2 if it lives for 100 years! Thus, along with forest conservation, the protection of great whales too can significantly reduce CO2 levels from the atmosphere. Baleen and sperm whales — in their giant bodies — can store a massive amount of carbon in the form of fats and proteins. This huge carbon sucking potential of these mammals make them one of the greatest carbon sinks. When they die and descend, they take this stored carbon in their carcasses deep into the ocean floors where the carbon remains out of the atmospheric cycle for hundreds of years! A 2010 study revealed that baleen whales including blue, humpback and minke whales can move 30,000 tonnes of carbon into the deep sea per year as their carcasses descend. Researchers say this carbon sink capacity could increase by 160,000 tonnes a year if we could boost the population of great whales to their pre-commercial whaling size.
Whales can help sequester carbon in other ways as well. Their excreta can release an enormous amount of nutrients into the oceans. These nutrients — mainly nitrogen, phosphorus and iron — help microscopic creatures like phytoplankton and marine algae to grow which, in turn, can remove more carbon out of the atmosphere through the process of photosynthesis. They have been estimated to pull out 40 per cent of all the CO2 emitted into the atmosphere.
In the last couple of years, we have seen massive die-offs of whales, especially in North America. Climate change has been warming ocean temperature and as a result, sea ice has been melting in the polar regions, which has threatened the Arctic and Antarctic ecology. The disturbance in these regions which are the feeding grounds of many species of whales might have triggered the recent die-offs. Warmer ocean temperatures and shrinking ice sheets have affected the benthic habitats of the creatures which whales feed on. This shortage of food, coupled with their growing population since whaling stopped, have been starving and killing the whales. Thus, to put a brake on future die-offs, it has become imperative to conserve whales so that we can reduce some impacts of climate change by carbon sequestration via whales.