Why climate credits for solar geoengineering are a bad idea

Buyer beware: There’s a questionable new type of climate credit for sale.

Traditional carbon offset credits, for example, for planting trees or protecting forests, have a record of failing to reduce greenhouse gas emissions. Now, a startup is selling credits for its attempts to manipulate the planet’s ability to reflect sunlight, a controversial response to climate change called solar geoengineering.

A group of prominent scientists published a letter yesterday warning that this type of climate intervention is nowhere ready to be deployed commercially and probably never should. A big name in the letter is James Hansen, a former NASA scientist now at Columbia University who is famous for sounding the alarm about climate change in congressional testimony in 1988.

This kind of climate intervention is nowhere ready to be deployed commercially and probably never should be

The letter calls for further research into the potential impact of solar geoengineering, which could reduce some of the risks posed by climate change or possibly create new problems. Given this uncertainty, scientists have stopped advocating solar geoengineering as a tactic to combat climate change. And they don’t think it should be implemented without a “thorough international assessment” of its potential impacts and “international decision-making” about how to use these technologies.

The statement comes after solar geoengineering startup Make Sunsets attempted to shoot reflective particles into the atmosphere from Reno, Nevada, this month and from Baja California, Mexico, last year. The idea is to simulate the way debris from volcanic eruptions reflects solar radiation, which temporarily cooled the planet in the past. What this actually looks like is two of the co-founders lighting fungicide on a grill, using the resulting gas to fill weather balloons with reflective sulfur dioxide particles, and then releasing the balloons.

Have Sunsets sell “cooling credits” at $10 per gram of sulfur dioxide you emit. Each gram is supposed to offset “the warming effect of one ton of carbon dioxide for one year.” But the company has no appreciable impact on the climate. To start, very little sulfur dioxide is released to make a difference against the billions of tons of pollution released annually by burning fossil fuels. And Make Sunsets hasn’t been able to collect concrete altitude data on the five balloons it’s launched yet, so it doesn’t know if the reflective particles it launched have reached the stratosphere where they’re supposed to do their job.

The Sunsets balloon launch has mostly succeeded in pissing people off who really want to see more legitimate research in geoengineering. “There can be no room for selling snake oil,” reads a Feb. 13 press release from SilverLining, a nonprofit organization that supports geoengineering research. “SilverLining strongly condemns Sunsets’ rogue releases of materials into the atmosphere and its efforts to market fraudulent ‘cooling credits’.”

“There can be no room for selling snake oil.”

Mexico said it would ban solar geoengineering experiments after the Make Sunsets balloon was launched there. The move was intended to protect nearby communities and the environment, according to Mexico’s Secretariat of the Environment and Natural Resources. Releasing too much sulfur dioxide has the potential to cause acid rain, irritate people’s lungs, and even exacerbate the Antarctic ozone hole. There are still a lot of unknowns when it comes to possible side effects.

Even if scientists gain a better understanding of the impact solar geoengineering might have and decide that the benefits outweigh the risks, monetization is still fraught with risk. “You will likely never be a suitable candidate for an open market system of credits and independent actors,” says the letter posted yesterday, as it “does not address the cause of climate change.”

What causes climate change, of course, is greenhouse gas pollution from all the fossil fuel power plants, factories, and gas-guzzling vehicles. It is humanity’s failure to reduce this pollution that has brought us to the puzzle that has made some scientists think of such a dangerous step as geoengineering now. Carbon credits, whether from solar geoengineering or conventional tree planting schemes, do nothing to prevent this pollution.

Sure, trees can absorb and store the carbon dioxide that’s causing the planet to heat up. But when they die, burn, or cut down, they release it again. It is not a permanent solution. Nor is it the kind of solar geoengineering that tries to make the sun set. Sulfur dioxide doesn’t stay long in the atmosphere, which is why the startup’s credit of just $10 is supposed to represent a year’s worth of cooling.

So if you want to make an impact this way, you have to develop a habit. If effective on a large scale, this type of climate intervention becomes addictive. Once you stop injecting reflective particles into the atmosphere, the world starts to warm up again—rapidly. Even volcanic eruptions that released enough sulfur dioxide to affect global temperatures had a short-lived effect. The 1991 eruption of Pinatubo cooled the Earth’s surface for about two years.

The world is already struggling to kick its fossil fuel habit. Credit can also lead to addiction. And if we’re not careful, we could waste what little time we have left to take real action on the climate crisis before it gets worse.

Make Sunsets founder Luke Iseman said in an email to the edge. “The question for me is what do we do in the face of uncertainty. Do we take actions that we know will create coolness and thus save lives, or do we wait for some international consensus that may never come?”

There is no evidence to support Iseman’s claims about geoengineering saving lives. But there is plenty of evidence that a clean energy transition can happen.

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