Kenya tests new method to combat climate change

Scientists at the KMFRI labs in Mombasa on Wednesday /BRIAN OTIENO

German and Kenyan scientists are studying a carbon removal method in the Indian Ocean to see if it can curb climate change without harming ecosystems.

The scientists, drawn from Geomar Helmholtz Centre for Ocean Research, Kenya Marine and Fisheries Research Institute, Ocean Climate Innovation Hub Kenya and Technical University of Mombasa, want to test whether the Ocean Alkalinity Enhancement (OAE) is safe for marine life.

OAE is a marine carbon dioxide removal technique that adds alkaline substances like limestone, olivine, or sodium hydroxide to the sea water.

This accelerates the natural, slow weathering process, allowing the ocean to safely store billions of tonnes of carbon dioxide as bicarbonate for more than 10,000 years while simultaneously combating acidification.

Added alkaline materials neutralise dissolved carbon dioxide in surface waters, creating a deficit that induces the ocean to absorb more carbon dioxide from the atmosphere to restore balance.

Leila Kittu [R], a marine biogeochemist at Geomar Helmholtz Centre for Ocean Research, with a sample of Indian Ocean water in Mombasa on Wednesday /BRIAN OTIENO

Leila Kittu, a marine biogeochemist at Geomar Helmholtz Centre for Ocean Research, tests the alkalinity of the Indian Ocean in Mombasa on Wednesday / BRIAN OTIENO

Support staff with samples of sea water in the Indian Ocean in Mombasa on Wednesday /BRIAN OTIENO

Leila Kittu, a marine biogeochemist at Geomar Helmholtz Centre for Ocean Research, said the experiment is one among other 17 experiments, part of global inter-comparison project called Ocean Alkalinity Enhancement Pelagic Impact Intercomparison Project.

“This project aims to understand the environmental impact OAE across different geographical locations,” Kittu said.

Some 17 countries, covering all continents, are interested in the project.

It is the only such experiment being done in Africa.

The experiment is being done the KMFRI laboratories in Mombasa.

“What we are aiming to understand is how tropical ecosystems where temperatures are high and productivity may be low will actually be impacted by such a technology if it were to be done in these waters,” Kittu said.

The experiment started on Wednesday last week and is expected to last two weeks.

“We will be collecting water samples regularly from tanks that we’ve just filled with sea water today and we monitor the community in the water and how it responds to the changes of alkalinity that we effect,” Kittu said.

“Our alkalinity level is about 500 micromoles per kilogramme and this is a level that we project might not be so lethal for organisms. We are trying to understand what the threshold for this system is,” Kittu said.

Kenya Marine and Fisheries Research Institute’s Joseph Kamau said there is excess carbon dioxide in the atmosphere leading to the global warming phenomenon.

“Even if the world stops generating or emitting carbon dioxide, we still have a problem. So the exercise that we are doing is actually coming up with a solution to remove carbon dioxide from the atmosphere so that we can mitigate the impact of climate change,” Kamau said.

He however said to do this, they have to understand how the new technique will affect the biodiversity in the ocean.

Ali Shee, a chemist in the department of chemist and biological sciences at the School of Pure and Applied Sciences at TUM, said carbon dioxide is the major contributor to global warming.

Its removal from the ocean is meant to minimise global warming to less than 1.5 degree celsius.

Removal of carbon dioxide from the environment can be done in various ways.

These include the terrestrial environment where the common afforestation is done so that the trees can absorb carbon dioxide form the environment.

There is also the direct air capture where carbon dioxide is sucked from the atmosphere and stored underground through various absorbents, then it is removed and pumped underground.

“Another option, which we at TUM are interested in because we are the only university at sea level, is to look at how to use carbon dioxide removal techniques using the resource we have, and that is the ocean.

“As you know the ocean is more than 75 per cent of our earth and we can use this vast resource both for economic activities as well as for fighting climate change,” Shee said.

Marine carbon dioxide removal is not only about mangroves, sea grass and salt marshes as the options which most people know of, Shee said.

“People forget that the ocean itself is a resource and the ocean water can be used for carbon dioxide removal from the atmosphere. That is the purpose of this experiment which we want to do together with our colleagues from the University of Tasmania, Georma and our partners here in Kenya, Kemfri,” Shee said.

The scientists will be looking at the phytochemical communities and how they will be impacted when the alkalinity of the ocean is changed.

Normally in Kenya, the pH is about eight.

The pH scale (0-14) measures the acidity or alkalinity of a solution based on the hydrogen ion concentration.

A pH of seven is neutral (pure water), below seven is acidic while above seven is alkaline.

“We want to see if we increase to maybe 8.5 or closer maybe to nine, what impact it will have on the phytoplankton community and maybe later we shall also look at its impact on other marine ecosystems,” Shee said.

Master’s students at TUM are participating in the research which will culminate in manuscript preparation and production as well as preparation of their thesis.

Undergraduate students are also taking part in the work, which benefits them from the training and capacity building they are getting.

“Currently, we don’t have a curriculum that trains people on marine carbon dioxide removal but it is an emerging technology that we at TUM want to take advantage of and leadership in order to scale up this type of research,” Shee said.

He said OAE is an opportunity to create new jobs because it will need new curriculum, technology and skills.