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Killing toxic algae can halt climate collapse

After COP27 failed at addressing our planetary emergency, this is the giant leap the world needs to save the earth
By one estimate, treating a severe algal bloom of just one hectare can remove more than 100 tons of CO2 within a few short days. (algal bloom image courtesy)
By one estimate, treating a severe algal bloom of just one hectare can remove more than 100 tons of CO2 within a few short days. (algal bloom image courtesy)

Scientists tell us an irreversible climate breakdown is cresting the horizon: temperatures and sea levels rising, glaciers and sea ice receding, epic floods and persistent droughts worsening. And yet the United Nations’ 27th climate change conference known as COP27 failed to match the urgency of the moment. By preserving the status quo, meager at best, it neglected to ease concerns about our planetary emergency.

COP27’s greatest failure was its lack of new targets or commitments to accelerate the pace of decarbonization that would attack global warming like our lives depend on it. By the time the vaunted conference staggered to an overtime finale, the final text failed to go beyond 2021 Glasgow Climate Pact language calling for a “phase down of unabated coal” in addressing warming. Thus, hopes of limiting global temperature rise to 1.5 degrees Celsius continue slipping away as global emissions remain at record highs. But there is a solution and it is available, economical, and scalable.

Keeping the 1.5C target alive cannot be achieved simply by reducing emissions, it requires active carbon dioxide removal on an unprecedented scale, something that must occur within the narrowest of windows. Indeed, this can be achieved if we focus carbon removal efforts on water, the most powerful, natural carbon sink on the planet.

Within our vast oceans, lakes, and wetlands – and, in fact, all natural water bodies on earth – are microalgae, which absorb atmospheric CO2 at a phenomenal rate, removing gigatons of carbon through their natural process of photosynthesis and sequestering it at a much faster rate than the world’s forests. This so-called blue carbon reduces the impact of greenhouse gasses on our planet. Therein lies the true, possibly only potential for carbon removal at scale.

Microalgae generate oxygen and use carbon as a source of energy. Scientists have been studying their carbon sucking superpowers for years. When microalgae multiply rapidly, they can produce toxins and form blooms that choke entire aquatic ecosystems by blocking out sunlight and depriving organisms of oxygen, ultimately creating aquatic dead zones. Climate change is exacerbating this cycle, fueling a global pandemic of toxic algae from western Lake Erie in the US to Elands Bay in Africa to Lake Dianchi in China and countless water bodies in between.

But when infected oceans, lakes, rivers, and wetlands are treated and toxic algae are killed, they sink to the bottom of the water body along with the carbon they have sequestered, and they remain there deep within the sediment for thousands if not millions of years, essentially locking away carbon permanently. By triggering and accelerating an entire toxic algae population collapse, colossal volumes of carbon can be scrubbed from the atmosphere, improving water quality as well as water availability with the same stroke.

What does this look like in practice? There are enough toxic algal blooms on the planet to make a significant impact. By one estimate, treating a severe algal bloom of just one hectare can remove more than 100 tons of CO2 within a few short days, allowing healthy algae to grow in their place and restoring ecosystems in short order. Now imagine this carbon removal process at gigaton scale.

COP27 can be applauded for its landmark climate compensation fund to help poorer nations pay for the devastating effects of a climate crisis they did not create. But in order to stave off even more detrimental – and ever more expensive – climate impacts, we must adopt new solutions for climate mitigation. We must look to water.

As UN Secretary-General Antonio Guterres stated at the conclusion of COP27, the world still needs a giant leap on climate ambition. If we want to pull the planet back from the brink, we must not only slash emissions, shore up vulnerable nations, adopt renewables, and increase resilience, it is imperative that we focus carbon removal efforts on our oceans and other water bodies to sequester CO2 at gigaton scale. By capturing CO2 from the air and sinking huge volumes of algal bloom biomass in the water, we, as a species, will have a real fighting chance against global warming.

About the Author
Eyal Harel is a clean water advocate and CEO of BlueGreen Water Technologies, a global water-tech company whose mission is to restore, safeguard, and optimize the health of water bodies worldwide.