How Can We Address Climate Change Besides Limiting Emissions?

From where I sit, eliminating emissions is only half of the equation when it comes to fighting climate change. If we all stopped burning fossil fuels tomorrow, all that CO2 would still be in the atmosphere, and would remain there for centuries(?).

Should we be planting billions of trees? Is scrubbing CO2 from the atmosphere possible even in theory? Is there research going on into this? Is there anything else that would help, even in theory?

Volcanoes can help, in the short term. Perhaps we can create a similar effect by release some substance in the upper atmosphere to block the sun’s rays?

This link is a about volcanoes, not about human efforts to duplicate the affect.

Obviously, anything that creates carbon - trees, grass, plankton, whatever. The catch is, in the “circle of life” much of that stuff eventually becomes CO2 again. So the key is to find growth material that grows fast but does not disappear fast. I thought I saw a suggestion once about forests of bamboo.

then the issue is scale - how many gallons of gasoline does 1 acre of bamboo represent?

We need to build more nuclear power plants.

That would be an example of reducing emissions.

This was discussed in Freakonomics:

The most controversial of these solutions – a “stratoshield” — involves the controlled injection of sulfur dioxide into the stratosphere to cool ground temperatures, which mimics the natural cooling effects of a big volcanic eruption like Mount Pinatubo. This sort of “geoengineering” solution is intensely disliked within environmental circles, and we discuss the reasons why. And we discuss why, if global warming gets worse, it might still be a good idea to consider further research on the stratoshield. We also discuss a much more environmentally friendly anti-warming solution from I.V. that uses salt-sea spray to increase cloud reflectivity.

I don’t have the book in front of me, but I recall they talked about the humungous accumulation of sulfur at the Athabasca tar sands site (do a google-image search for “athabasca tar sands sulfur”, and you’ll see shots of absolutely enormous squared-off heaps). They described the idea of using this sulfur to generate airborne sulfur dioxide and piping that up to the stratosphere to generate elevated concentrations of sulfate, which would help reflect some incoming sunlight away from the earth, counteracting the increased heat retention properties that CO2 accumulations are currently causing.

People talk about carbon sequestration, but doing it on a useful scale is a pretty tall order. If you generate biomass, you have to somehow prevent that biomass from decomposing. If you inject it unground (where coal and petroleum had previously been sequestering said carbon), you need to be confident that it will stay there for the long haul.

According to a crude estimate I did just the other day, in the past couple hundred years we’ve extracted from the earth a cube of coal 6 km on a side, and a cube of petroleum almost as massive, and turned it all into CO2, thus increasing its volume by a factor of about 500. Even if you could imagine filtering all that CO2 out of the atmosphere, I’m not sure where we’d put it.

And it wouldn’t do anything about the elevated levels of CO2 we’re already facing.

Regeneration of soil, or, especially, peat bogs is probably one of the better methods, certainly much more effective at long-term sequestration than trees are. In the wrong location, or with the wrong tree type, there’s pretty good evidence that trees can actually be a net producer of carbon, due to their effects on soil dynamics.

Peat is effectively carbon, in a stable form, and a bog self-perpetuates once a bog is started off, in the right location.

Unfortunately, a bog is a much harder sell to the general public than tree planting, and there’s still quite limited research in how to most effectively artificially carry out restoration. They’re not viable in all locations either, so it’s something which would involve some countries disproprortionately losing farmland, because they’re the most suitable location.

It could.

Sequestering CO2 costs energy, and if you are trying to do it by powering it with fossil fuels, you are playing a foolish game. If you are getting the power from nuclear, then at least you can come out ahead.

Any insight on this issue? Does the CO2 level remain essentially constant if we stopped adding to it? Or does it decline over time for some reason?

To make a long story short, there is no profit to be made.

The two primary ways other than reducing emissions are, as mentioned

  1. Carbon sequestration. This is possible, and there is active research going into it. The simple form is “plant a lot of trees and then use them in some way that keeps the wood as wood for a long time”, but there are other mechanisms like pumping liquid CO2 to the bottom of the ocean where it would be stable at high pressure and low temperature.
  2. Active Cooling. This is generally putting something up into the atmosphere that will reflect away more of the sun’s energy.

There is active research in both areas. Active cooling is likely more economical, but is potentially a lot riskier since the climate is a complex system. Sequestration is unlikely to be economical without an effective carbon tax, and as pointed out above, likely requires a substantial increase in power generation from non-carbon sources.

Depends on what you mean by the “long haul”. Sequestration could be a medium term solution, if it were cheap and developed, when combined with reduced emissions, which would avoid as bad a medium-term catastrophe even if the sequestered carbon nonetheless gets reemitted again on a century timescale.

I won’t address “should we” in FQ but you can find relevant technologies here:

Kelp carbon sequestration made headlines for its attractive simplicity and low cost. But as this article points out, there’s still a lot of unanswered questions about it.

On the trees idea, our western North American forests already have too many trees - as we’ve been extinguishing every fire for the last 100 years, they are severely overgrown, and the recent massive forest fires are trying to get things caught-up. Better to restore the hundreds of square miles of tropical rain forest where trees should be growing densely and where destructive wildfires are less of an issue, IMHO.

But, I think the problem is too big for one solution to solve. Restoring tropical rain forests is only viable in a narrow band of latitudes, and wont be enough. Tinkering with the climate has yet to be proven, and likely has some unintended consequences, but seems most likely to be able to scale in the way needed, on a global level. I think the core problem is solutions are needed that not only limit the amount of CO2 being added to the atmosphere, but that will also remove more than what is being added, for a net reduction overall. The scales of any solution/combination of solutions needs to be enormous, will be costly, and are likely to be disruptive to the ways modern civilization is accustomed to living.

There’s also the issue of the Amazon rain forest. Brazil needs to stop the ongoing deforestation.

One of the problems with using plants to sequester is that they may sequester other things that we’d like to keep in the environment for our use, like phosphorus.

One idea in the “close but no cigar” realm is adding iron to the oceans. Iron is one of the limiting nutrients in ocean life. Adding a modest amount can cause increased algae growth. Which leads to carbon sequestration … sort of. After a lot of optimism things don’t seem so great now.

It was the oceans that absorbed a lot of CO2 for a long while up until the later 1900s. Once they got saturated then things really took off in terms of warming.

Figuring out how to get the CO2 levels down in the oceans so that they can do a better job absorbing it from the air would be a big help.

There’s yet another option: Accept that temperatures have risen, and as long as we have nonzero net emissions will continue to rise, and adapt to those increases in temperature. This might mean, for instance, moving hundreds of millions of people away from current coasts, and completely changing what crops are grown where and how.

And yet another option: Accept rising temperatures and not attempt to adapt to them, with the result that hundreds of millions of people die, many crops fail, and so on.

I mention these alternatives not to advocate for them, but to give perspective for the other options, by giving something for which we can compare the costs.

I think we should be considering your first option even if we think we found the silver bullet for climate change. Even for areas not prone to coastal flooding, investment in infrastructure to support cooling (power grids, industrial AC for schools, hospitals, etc.), for example, needs to be fast-tracked - as we are seeing in Europe and UK with this heat wave. While we should seek solutions, we should also plan for impacts we are already seeing.