(New York) The United States should look into the possibility of altering the world’s oceans – for example, by passing an electric current through them – to make them absorb more carbon dioxide in order to combat climate change, recommends the National Academy of Sciences.
The committee highlights six ways that possibly can help the oceans capture more of the heat-trapping carbon dioxide. The most promising tactics, researchers say, are to make oceans less acidic with minerals or electric shocks; adding phosphorus or nitrogen to stimulate the growth of plankton; and to create gigantic algae farms.
It is not known, however, whether these strategies would actually work, how much they would cost, and whether they would not end up being more harmful than helpful. The committee of scientific advisers to the federal government therefore proposed on Wednesday to spend more than US $ 1 billion over the next decade to spot potential dangers and identify the methods most likely to induce the world’s oceans to mop up more carbon.
The possibility needs to be explored, the academy said, because more than just reducing emissions is likely to be necessary if the world is to meet the targets of the Paris Agreement signed in 2015, namely to limit future warming to only a few fractions of degrees compared to today.
By mid-century, the world will likely have to remove about ten billion metric tonnes of carbon dioxide from the atmosphere each year, the report says.
Previous reports from the academy had looked at geoengineering as well as other carbon uptake initiatives, such as planting more trees. The new report, funded by non-profit group ClimateWorks, examines what is currently absorbing most of the excess carbon dioxide: the oceans.
The report does not propose geoengineering the oceans, but rather to explore how this could be done.
“We are not answering the question ‘should we?’ Said committee chair Scott Doney, a biogeochemist at the University of Virginia. The question is “can we?” And if we do, what would be the impacts, and we try to make it clear that all of these approaches will have impacts. What would be the consequences for the environment? ”
The report examines the following strategies for getting the oceans to absorb more carbon dioxide from the atmosphere:
- Using an electric current to make the oceans less acidic. More alkaline water can eat up more carbon. It would also help fight one of the worst harms of climate change – acidic oceans that damage crustaceans and corals. Scientists are confident it would work since it is about basic chemistry. The report recommends funding of US $ 350 million for research.
- Using minerals to make the oceans less acidic. This method would be quite expensive and risky. The report recommends between $ 125 million and $ 200 million for research.
- Add nutrients like phosphorus or nitrogen to the ocean surface. This would stimulate the photosynthesis of plankton, which would absorb carbon dioxide before sinking. The committee said it was between moderately and highly confident that it would work, with moderate risks to the environment. We recommend US $ 290 million in research and field experiments.
- Cultivation of algae. Plants would absorb carbon before they sink or are sent to the bottom of the ocean. Scientists have moderate confidence that it would work, and the environmental risks range from medium to high. The committee suggests $ 130 million in research.
- Restoring ecosystems would help marine life, plants and the coastal environment to regain health and absorb more carbon. The risk to the environment is low, but the chances of success are moderate at best. The report suggests funding of US $ 220 million for research.
- Artificial waves to stimulate the growth of plankton. The report recommends funding of US $ 25 million, since the risks are high and confidence in efficacy is low.
Breakthrough Institute climatologist Zeke Hausfather, who was not involved in this work, believes that electrical and chemical approaches to changing ocean acidity “have the greatest potential for long-term carbon removal,” on a large scale, enough to make a significant difference ”. He is less convinced of the effectiveness of fertilizers in stimulating the growth of plankton.
Cornell University climatologist Natalie Mahowald, who was also not involved in the work, said that “carbon removal and sequestration is required to meet climate targets. […] The potential of the oceans is enormous, poorly understood and little exploited ”.
But Pennsylvania State University climatologist Michael Mann warns that simply eyeing the oceans is harmful since polluters and governments can use it as an excuse “to delay or downplay the only safe solution for the climate: drastically reduce our consumption of fossil fuels ”.
But it makes sense to be ready, Doney said. “If we don’t start looking at this now, a little later we may have to make decisions on the basis of insufficient information. ”
The decision whether or not to fund research is in the hands of the President and Congress of the United States.
Earlier this week, the Department of Energy called on businesses and organizations to demonstrate technologies that could remove carbon dioxide from the atmosphere or reduce emissions, saying the infrastructure law passed last month provides for funds for this purpose.