Tuesday July 25, 2017

Can geoengineering technology combat extreme weather?

Cloud seeding efforts in Alberta, where the technology is being used to reduce the severity of hail.

Cloud seeding efforts in Alberta, where the technology is being used to reduce the severity of hail. (CBC)

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As wildfires burn through B.C., residents hope for weather's helping hand in firefighting efforts.

"In the last two or three days ... we've been getting lucky ... we had a downpour of rain a few days ago. It dampered down the smoke quite a bit, so the breathing is getting better. It's getting clearer and calm," Evan Fuller, a Riske Creek, B.C., resident, told CBC News this week.

Rain. Precipitation. A few good downpours are what the B.C. Interior needs right now — and they're not alone.

With the rash of extreme weather events across the country — from wildfires, to flooding, and everything in between — some are exploring more seriously how we may engineer weather systems ourselves.

One particular process of manufacturing rain called "cloud seeding" is garnering attention as a potential option for controlling extreme weather, but like most geoengineering strategies, the technology remains controversial.

'There are some potential downsides that we don't think about.' -  Robert Jackson, Stanford University's earth system science department chair

Daryl O'Dowd, a consulting meteorologist who's advised Canadian companies and government bodies on cloud seeding, says we have nothing to fear. Cloud seeding has been used in Canada for half a century, and 40 to 50 countries currently deploy the technology, he tells The Current.

"We actually do a really good job making rain and making snow here in Canada," O'Dowd explains.

"Almost every raindrop we get starts as an icicle or a snowflake ... [For cloud seeding,] we put materials into the clouds and fool the clouds into thinking there's natural ice … It builds on the natural ice crystals and the artificial ice crystals fall out as rain."

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Cloud seeding is the release of silver iodide - in some cases, other substances - in clouds to encourage precipitation. (CBC)

In Canada, the process was first used in 1956 when a group of private farmers suffering significant hail losses out west hired a U.S. weather modification firm to conduct a cloud seeding program.

That program ran until 1985, stopped for a while, and then restarted as the Alberta Hail Suppression Project, says O'Dowd.

"In Alberta, we have high-value houses and cars, and there's a hail project here that attempts to mitigate the amount of hail that damages urban structures," he says. 

"If you can make more snow, you can make more rain, and through that same process you can diminish the amount of hail coming down."

O'Dowd says digital technology has demonstrated that cloud seeding technology can manage severe weather patterns.

"We have radar now that can actually inspect clouds individually and compare …  And in many, many, cases not every case, but in many cases, there's a distinct signature that indicates that the severity of the individual storms that we do cloud seed do decrease."

But Stanford University's earth system science department chair, Robert Jackson, is not so convinced.

"I think the evidence is that you might be able to get a little more rainfall — for instance, squeeze a couple of extra drops of juice out of a lemon — but you can't make a second glass of lemonade," Jackson tells guest host Laura Lynch.

"Most times we don't get a statistically significant result. Frankly, the evidence is pretty weak that cloud seeding works."

 'Does a cloud seeding event in Alberta keep a farmer in Saskatchewan from getting rain that he or she might have received?' - Robert Jackson

With respect to combating wildfires by making rain, O'Dowd admits the technology likely can't help. 

"One of the difficulties with forest fires is that the smoke itself has a sterilizing effect on the clouds above. The fires, fire smoke, and the particles make the cloud droplets much smaller, and it makes it difficult for them to actually naturally precipitate, let alone through processes of artificial injection. The clouds are sterile after a forest fire."

But Jackson maintains we'll likely be seeing more of cloud seeding, and it's in our best interest to thoughtfully consider the technology's application. 

"There are some potential downsides that we don't think about too much. One issue is where the rain would have fallen if you hadn't cloud seeded. Does a cloud seeding event in Alberta keep a farmer in Saskatchewan from getting rain that he or she might have received?"

"There are important questions to be answered. People may get better at it, but there are also people who stand to make a lot of money at it. It's a mix — what we're seeing right now — of all of those factors."

Listen to the segment at the top of this post. 

This segment was produced by The Current's Idella Sturino and Ram Sharvendiran.