Hacker News Reader

Comment by ForHackernews | Hacker News Reader

> if the two alternatives are global catastrophe, or aggressive geoengineering, do you really think geoengineering won't happen?

Why hasn't it happened already, then? In case you haven't noticed, we're already staring down the barrel of global catastrophe. The problem is that it's happening on a scope that our human systems aren't set up to address.

It's interesting how much faith supposedly hard-nosed engineers are willing to put into imaginary future technology that doesn't exist, but which will supposedly be invented and deployed at a planetary scale in the next 10 to 20 years.

View on HN

They already have estimates for the sun shade idea, so probably the engineers are capable of doing what they say.

It's interesting how you cling to doom and gloom, and don't even bother researching alternatives.

Do you really honestly think a trillion-dollar giant space mirror is something that could/will happen circa 2040 or so?

To me, this sounds like Elon Musk's science-fiction predictions of Mars colonies by 2020.

A recentish one places an estimate at 10B initial costs, and 10B maintenance. 20B is doable by the US alone, yes.

Sometimes the truth is stranger than fiction, it's why you must research. In this case the truth may well be that humans have an easier time making the sun shine less rather than lowering our carbon footprint.

https://en.wikipedia.org/wiki/Space_sunshade

Everything I find about this idea looks like pie-in-the-sky speculation and back-of-the-envelope estimates. As far as I can tell, nobody is making serious engineering proposals for this idea. IMHO, you are far too sanguine.

Which numbers in particular do you have problems with?

As a point of reference, the Galileo navigation constellation apparently costs about 10bn (€ not $, but call it even): https://qz.com/1264365/brexit-is-breaking-up-galileo-europes...

That system is essentially a modern re-implementation of GPS, a known, proven technology.

To suggest that this untested, unproven, highly speculative solar shade project would cost the same is laughable to me. You're also totally discounting the unintended consequences and second-order effects of trying to engineer the climate.

Your point of reference includes 2 ground control centers, and 30 satellites. To suggest that launching a single satellite would cost the same is to me, laughable.

This if anything proves my point, nothing seems insane about launching a lens into space. We have satellites now, this is essentially one with a lens.

https://en.wikipedia.org/wiki/Galileo_(satellite_navigation)...

I'm not discounting anything, just assuming scientists and engineers involved have done their job.

> One proposed sunshade would be composed of 16 trillion small disks at the Sun-Earth L1 Lagrangian point, 1.5 million kilometers above Earth. Each disk is proposed to have a 0.6-meter diameter and a thickness of about 5 micrometers. The mass of each disk would be about a gram, adding up to a total of almost 20 million tonnes.

> Such a group of sunshades would need to occupy an area of about 3.8 million square kilometers if placed at the L1 point. The deployment of the flyers is an issue that requires new technology. Large railguns or coilguns are proposed to fire a capsule containing a million shades into space every 5 minutes for 10 years using 20 separate launch sites.

This is science fiction.

Perhaps, but that is the 5T one, the "one fresnel lens" option or "one diffraction grating" option are cheaper and seem more feasible.

That said, if scientists believe that all they lack is money, who are you to tell them otherwise.

Oops: https://www.theatlantic.com/science/archive/2018/08/solar-ge...

(Not space lenses, but another risky, poorly-understood geo-engineering proposal)

Seems unrelated, but I'm glad that idea went through scientific review.

Reply on news.ycombinator.com