Tuesday, February 10, 2015

Barking Mad and David Keith: on geoengineering

"I think you’ve stated that this is not the right approach — that cutting CO2 as much and as quickly as possible is the right approach, but it’s not happening so... "

Saw an article in Slate today on Geoengineering that reminded me of a recent one from David Keith.
I think the important thing on geoengineering is it's unlikely to happen as an international effort, and it is likely to happen - and like the Cuban missile crisis, many will be scared.
And not much will happen.

Maybe I'm crazy though - from these two articles it seems somebody must be.

Harvard’s David Keith Knows How to Dial Down the Earth’s Thermostat. Is It Time to Try? | Re/code:
I work across a lot of pieces of research, but I’d say the frontiers are trying to understand how much effectively turning down the sun, solar geoengineering, actually reduces the climate risk that people care about: Crop losses, ice sheets melting, temperature extremes, or what have you.
There’s no question it reduces the global average temperatures; even the people who hate it agree you could reduce average global temperatures. The question is: How does it do on a regional basis?
By far the single most important thing to look at on a region-by-region basis is the impact on rainfall and temperature.
And the answer is, it works a lot better than I expected. It’s really stunning.

A lot of us thought that, in fact, geoengineering would do a lousy job on a regional basis — and there’s lots of talk on the inequalities — but in fact, when you actually look at the climate models, the results show they’re strikingly even.
Now, it’s not perfect and there are some things it won’t do. Turning down the sun does nothing for ocean acidification.
But it looks like it can cut, like, 80 percent of the total variation in climate, which is really stunning.
In some ways we should be singing it from the rooftops. But the scientific community is so painfully scared of talking about it. These papers come out, and people find the best ways to say, well, it sort of works, but it’s really awful.
The fact is, people really appear to have found a way to significantly reduce the climate risk — by more than half, which is a big deal.
and, conversely, from Raymond T. Pierrehumbert on Slate: Climate Hacking Is Barking Mad

Albedo is the scientific term for the proportion of sunlight reflected back to space. If the Earth had 100 percent albedo, it would reflect all sunlight back to space and be a frozen ice ball some tens of degrees above absolute zero, heated only by the trickle of heat leaking out from its interior. Earth’s current albedo is about 30 percent, with much of the reflection caused by clouds and snow cover. I myself prefer the term “albedo hacking,” but “albedo modification” does pretty well. My colleague and report co-author James Fleming has called such schemes “untested and untestable, and dangerous beyond belief.” 
albedo hacking is still barking mad, but people are often driven to do barking mad things out of desperation, and we are heading to the breaking point now with our continued fossil fuel binge. But if it comes to albedo hacking, the result won’t be pretty. It won’t be some benign “Plan B,” but more like the constant fear of thermonuclear holocaust I grew up with during the Cold War. It will be the end of blue skies and crystal-clear starry nights, and the beginning of nightly blood-red sunsets. These are not the most serious consequences of albedo hacking, but they will serve as nightly visible proof of our moral failure. And there will be no exit, not for thousands of years (unless we figure out a way to suck CO2 out of the atmosphere). If the serious deliberative process counseled by the NRC report makes people stop and think about just how terrifying that world would be, perhaps the thought of a world with less reliance on fossil fuels would start to seem a lot less scary.


Andy Revkin has written on this; In Geoengineering Study, Science Academy Sees Merit in CO2 Removal, Risk in Reflecting Sunlight

No comments:

Post a Comment