What if there was a binding global resolution passed tomorrow mandating that all countries gradually close down their terrestrial resource extraction sites and instead source from asteroid mines? Would mining metals and other elements from space sources (moons, asteroids, etc.) in lieu of mining them from Earth provide any net benefit to environmental conservation efforts?
There would be an increase of pollution for a very long time because there is no infrastructure in space and it will take thousands of launches to start to put it there adding millions of tons of CO2 to the atmosphere. During this period there would be very little goods returning to Earth. And even when materials did start to arrive there would still be the need for a huge number of launches to provide for all the things that couldn’t be made in space. This might slowly change over time but I suspect the time frame would be of centuries rather than years.
So in summary any attempt to bring resources from space would require a massive effort that would cause a lot of extra pollution in the short term before we saw a benefit. In the long term there could well be a benefit but that might be centuries away.
Would mining metals and other elements from space sources (moons, asteroids, etc.) in lieu of mining them from Earth provide any net benefit to environmental conservation efforts?
It would give no benefits, only additional negative effects.
First of all, whatever you want to send out in space, has to be built here on Earth with materials we have here in Earth. This means mining them here. To send 3 guys on the Moon we used about 3000 tons of materials per rocket. To build a mining station somewhere we would much more than that.
Then, once we have somehow created the first mining stations reducing Earth like a form of Gruyere and we can stop mining on Earth, we will have the not so negligible effect of all the kinetic energy from the re-entering, fully loaded vehicles which will be dumped in the atmosphere.
Top it with the needed processing, which will still happen on Earth with resources present on Earth..
Associated Benefits may have a large positive Effect
As with many aspects of space programs, it is not necessarily the space program itself that yields benefits, but the technologies that are enabled that come from it.
As an example, the Space Race in the Cold War, although it did consume copious resources, also created technologies that really created much more efficient technologies than would have otherwise been possible in communications, material science, automation and even administration and standards.
To perform asteroid mining, you would need many technologies to be developed, perhaps the following:
a large amount of automation in production: Efficiencies can probably be found in production of complex parts which could transfer to other industries (automotive, shipping or computing industries) increasing efficiency
advances in fuel technology: The good thing about mining companies is they look at the bottom line all the time - fuel is a major cost. It's reduction (through better efficiency or unique technologies) could also transfer to transport on Earth too.
advances in power generation: As is all the case in remote work, power is needed and lots of it. Any advances here could potentially be used on Earth, such as better solar power, or fusion reactors.
advances in remote automation: I work in Australia and because of isolation, mining is mostly done now fully automated (even trains have no drivers). This automation is now highly sought after by others around the world. Space mining would yield this benefit and several orders of magnitude more, with AI and self-repair or self-production technologies really coming to the fore.
Now the above could actually influence Earth in much more ways than just a simple mining operation. Even a 25% increase in say, solar panel conversion efficiency, would suddenly catapult this technology into mainstream use and replace all current power generation.
So in general, don't discount the effect of one development improving all associated ones, which could mean an enormous effect when considered in totality.
Once the humankind be able to make complex buildings in space (after one space elevator, maybe?) what would the excuse to keep all industrial plants on surface? There lots of sources mined in space, controled environment with less gravity (or more, depends of purpose), lots of energy of the solar panels (one space elevator can 35000 km of cables able to install). In the next step even colonies of workers turn in small cities in stations in space. Less hazardous activities in surface or in the atmosphere.
Then, yes. You made the space mining an eco-friendly thing.
However, no wait this happen today. Perhaps in 100 years, with luck.
There is a way to use materials in space that would help the environment, but not in the manner you are thinking.
Earth has a huge gravity well, which means that each kilogram of payload to be sent into space requires thousands of kilograms of propellant just to get it there. Re-entry in Earth's atmosphere also requires large amounts of thermal protection. By minimizing the mass sent up and down from the Earth's surface, you can dramatically help the environment. In other words, you want to source as much of your spacecraft's mass (including propellant) from outside of the Earth's gravity.
In-situ resource utilization (ISRU) is the extraction of materials from asteroids, moons, and other planets. Some possible examples include
- Extracting and purifying water, which can be used directly for cooling, growing crops, and human consumption.
- Growing crops for food.
- Producing propellant (hydrogen and oxygen) from water by electrolysis driven by solar panels.
- Mining and refining of metals, to produce the structure of spacecraft.
- Manufacturing solar cells.
These items are relatively simple to make, and could probably be done remotely by robots. They also comprise the majority of the weight of a spacecraft (particularly propellant). Many proposals for a crewed mission to Mars assume using ISRU to produce propellant for the return trip. Note that precious metals such as gold are actually not on this list!
There would still be some portions of a spacecraft (crew module, electronics) that are better made on Earth, because of the complex infrastructure required for manufacturing, and because of the need for careful testing. However, using ISRU for as much of the spacecraft as possible would minimize the mass of material that would need to be launched from Earth. In the long term, this would be good for the environment.