Scientists lay out plan to use air conditioners to save the world

Carbon dioxide could be captured and turned into fuel, combating climate change and keeping you cool.

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Eric Mack
4 min read

Converting all the air conditioners in Frankfurt's Trade Fair Tower could pull a thousand tons of carbon dioxide out of the atmosphere each hour.

City of Frankfurt

The problem is simple: Burning fuels for energy releases carbon dioxide into the atmosphere, which screws with our climate. One novel new proposal suggests converting all the world's power-hogging air conditioners from contributing to the problem to becoming part of the solution. 

The idea is that air conditioners can be retrofitted with existing technology enabling the cooling units to also collect carbon dioxide and water vapor from the ambient air.  The system would then take those ingredients and convert them, on site, into synthetic liquid fuels that can be used in place of the fossil fuel-based stuff that has put us in this climate mess in the first place.

"Anecdotally, A/C is amongst the most useful inventions of the twentieth century. With continued global warming, the prevalence of A/C will likely become more pervasive. Perhaps the use of A/C for making hydrocarbon fuels, if adapted globally as suggested, could be A/C 2.0 of the twenty-first century," reads a letter by researchers from Germany and Canada published Tuesday in the journal Nature Communications.

The technology to capture carbon dioxide directly from the air is not new. A handful of startups like Canada's Carbon Engineering have been operating carbon capture plants for a few years now and have attracted investment from the likes of Bill Gates and large oil companies. Tech also exists to use captured carbon dioxide as a raw material that can be converted into everything from construction materials and chemicals to food and fuel. 

Another company, Alabama's Global Thermostat, has been focusing on a design that can be retrofitted onto industrial smokestacks to capture carbon dioxide at the source.

But the notion of outfitting commercial and even residential A/C units with the same type of direct capture system and converting it to fuel, which the researchers call "crowd oil," seems to be a new one. 

To be clear, you can't yet buy a system to convert your A/C to a climate change-combating, synthetic fuel-producing factory. Rather, what the paper in Nature Communications suggests is a plan for quickly scaling up a system to drastically reduce the amount of carbon dioxide in the atmosphere, which scientists say may be at the highest point in human history and perhaps as far back as 3 million years

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The authors calculate that a capture system installed in the Frankfurt Fair Tower in Germany could remove over a ton of carbon dioxide from the air per hour. The same systems implemented in Germany's 25,000 supermarkets could capture around 1,000 tons an hour.

That's a lot of carbon dioxide, until you consider that human activity releases, on average, over 4 million tons of the stuff into the air each hour. Still, it's predicted there could be over 5 billion A/C units running around the world by 2050. If all those units are pulling carbon dioxide from the air rather than adding more, it could make an impact. 

And the International Panel on Climate Change said in a report last year that we need to make that kind of drastic dent in our global CO2 emissions, and fast. The IPCC says, to avoid the worst impacts of a warming planet, we should reduce those emissions to zero over the next couple of decades and start actually reducing levels of carbon dioxide in the atmosphere thereafter. 

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Could the key to making this happen actually be to turn the world's A/C units into carbon-collecting renewable fuel refineries?

There are some major challenges to overcome. Foremost, if the air conditioners are run on electricity powered by burning fossil fuels, it defeats the whole purpose. That means basically switching over to renewable energy as quickly as possible. The paper's authors estimate that to do this in Germany alone would mean covering half of all roof space in the country with solar panels. 

"This means that buildings populated by humans will act like inhabited technical photosynthesis systems, which is a very intriguing idea given the ever-growing number of human beings on this planet," the paper reads.

One bonus is that the fuels created by the system could be stored collectively and used during times when solar and wind power collection is not possible. But this brings up another challenge, which is how and where to store all the fuel that would be created from the A/C captured carbon. 

Increasingly, technologies and solutions like this are emerging to address the climate crisis, but putting them in place quickly will require some collective organizing, and fast. 

As the paper concludes: "In order to make this happen, social sciences are needed to investigate how individuals and organizations forming the rather diverse societies around the globe could be motivated to take collective action against global warming and support the implementation of the vision of 'crowd oil.'"