Experts say there are some deep-sea consequences of ocean-based climate mitigation technology. 

Oceans have been touted as the world's greatest ally against climate change, with potential to remove and sequester carbon dioxide, manage solar radiation or produce renewable energy. However, these technologies could have major effects on the understudied life deep in our oceans, argue an international team of scientists. 

They warn this could reduce fisheries, kill off biodiversity, and alter underwater nutrient cycles.

There is a growing recognition that climate interventions will likely be required to avert the most harmful effects of anthropogenic climate change. As a result, interest in using the ocean to remove and sequester carbon dioxide, manage solar radiation or produce renewable energy has rapidly increased. 

However, despite this attention, there has been very little discussion or focused research on the potential impacts these technologies may have on ocean biogeochemistry and ecosystems. 

This is particularly true for understudied deep-ocean regions, which are fundamental to the overall health of Earth’s oceans. 

A new study from the National Institute of Water and Atmospheric Research (NIWA) in the US highlights several proposed ocean-based climate intervention (OBCI) approaches, including those designed to manipulate the ocean to enhance its ability to absorb and store atmospheric carbon or increase its solar reflectance. 

Given the strong connectivity between the surface and deep ocean, the authors argue that any OCBI activity will have far-reaching impacts through the water column and to the seafloor. 

These impacts could have a variety of unforeseen and unwelcome consequences for deep-ocean ecosystem services, including changes to carbon and nutrient cycling, fisheries production, and biodiversity. 

According to the authors, these potential impacts must be better understood and be used to guide future OCBI policy and governance. 

“The urgency of the climate crisis demands an accelerated, focused research effort on the effects of OBCI techniques on deep-ocean physical and chemical properties and on deep-sea ecosystems and their services,” the scientists say.

“This will require partnering of academic deep-sea scientists and engineers, nascent or existing industries promoting the technologies, regulations, and funders.”

The full study is accessible here.