In the wake of the US withdrawal from the Paris climate accords, the rest of the world is continuing its work to reverse climate change and salvage the biome for humans and other animals. On the first of June, Climeworks, a spinoff founded by engineers Christoph Gebald and Jan Wurzbacher of the Swiss company Eth, switched on the first-ever modular carbon capture plant – a device engineered to remove carbon dioxide from the atmosphere.

Global efforts to reduce climate change have largely focused on reducing emissions of greenhouse gases – carbon and other particulate matter and gases that trap heat in the atmosphere, causing the earth to steadily warm, changing its climate and its livability for humans. However, merely reducing carbon emissions, it has become clear, will not be sufficient to prevent drastic changes to the climate that will affect food production, ocean levels, habitats, and our ability to sustain human life on this planet.

A study led by respected climate scientist James Hansen, who was formerly head of NASA’s Goddard Institute for Space Studies, found it necessary to bring dioxide (CO2) in the atmosphere down to low levels not seen in decades. The study recommends a target of 350 parts per million, down from a current level of 400 ppm, which itself is more than 40 percent higher than before the Industrial Revolution. 450 ppm is widely believed to be the upper limit to avoid the worst effects of global warming, and that swift action is required to avoid those levels.

However, global warming involves feedback loops – the warmer we get, the more the atmosphere heats up – and so the study states that current efforts, even as aggressive as the Paris accords, are insufficient to avoid disaster. Even zero increase in carbon emissions would not be drastic enough to prevent potential disaster. To gain control over climate change and reverse the effects of warming, countries must actually remove CO2 from the atmosphere, a process known as “negative emissions.”

This is where Climeworks comes in. Gebald and Wurzbacher had been researching direct air capture technologies as part of their masters studies at the Professorship of Renewable Energy Carriers at ETH Zürich. The technology absorbs atmospheric CO2 using a proprietary filter. When the filter has become saturated, it is heated to 100° Celsius. The heat releases the gas from the filter, and the gas is then pumped to a greenhouse where it can help grow cucumbers, tomatoes, and other vegetables, using the excess CO2 to increase yields by as much as 20%.

The company estimates that the prototype that went live on 1 June, 2017 will be able to move approximately 900 tons of CO2 from the atmosphere annually, which is a negligible fraction of the 10 gigatons per year that the Intergovernmental Panel on Climate Change recommends. However, the company believes it can quickly scale up the technology so that by 2025 the units will be able to capture and redirect one percent of the CO2 pumped into the atmosphere by burning fossil fuels. This company estimates it will require approximately a quarter of a million plants of this size to achieve the one percent goal.

Though the technology doesn’t result in negative emissions, recycling the carbon dioxide for other uses alleviates the impact on the atmosphere. Theoretically, negative emissions could be achieved by directing the CO2 into sequestered chambers in the earth, or by transforming it into substances like rock. But for now, simply removing it from the atmosphere is a big step in the right direction.

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