When arguing against investing in the development of CDR solutions today, CDR's opponents frequently cite the fact that our society still emits billions of tons of GHGs into the atmosphere. CDR, opponents argue, costs more than many GHG emission mitigation strategies, and removing a given quantity of GHGs from the atmosphere has the same effect on atmospheric CO2 concentrations as not emitting that same quantity of GHGs. If CDR achieves the exact same impact as GHG emission mitigation strategies, why would we bother pursuing CDR when we could focus our efforts on less-expensive alternatives that achieve the same goal? There are several reasons that, despite CDR's lack of short-term cost-effectiveness, I think it makes sense to pursue developing CDR solutions:
1. CDR might take a lot of development before it is more affordable -- starting that process now will help us scale CDR more cost-effectively when it is needed in the future.
As long as the world expects that it will only need to reduce (not eliminate or reverse) GHG emissions to prevent significant climate change, the case for investing in CDR today is not very strong. But if we need to both stop emitting GHGs and sequester some of the CO2 that we have already emitted, then CDR will be necessary at some point in the future.
If CDR is necessary, it will be important to have affordable CDR options, which will potentially take a significant amount of time to develop. Take solar energy for example, which has taken some 35+ years to just become cost-competitive with other sources of energy in some (but not all) locations:
Given that solar energy businesses share many characteristics with CDR solutions (capital intensive, commoditized market, heavily regulated, etc.), it is reasonable to conjecture that CDR will also take decades of innovation to become more affordable.
But when will we actually need to start investing heavily in CDR innovation? That is, when will we really need affordable CDR? The UN IPCC projects we will need to emit negative emissions as a society in 70 years or so (see below) to avoid significant climate change under its most aggressive emission reduction scenarios. This sounds like ample time to start developing CDR, but this 70 year timeline also assumes that we start drastically cutting emissions over the next decade.
Source: http://mitigation2014.org/ -- The blue lines show what emissions will need to look like to avoid 2 degree C climate change: note the lines going below zero after 2080 and the rapid downward slope of these lines by 2025...
If we don't cut emissions quickly over the next decade (which seems highly likely), we might need cost-effective CDR by mid-century instead of the century's end. And if we want to be prepared with cost-effective CDR solutions when we need to deploy them at scale, it would be prudent to start developing these solutions today.
2. Inexpensive CDR could help increase political support for fighting climate change.
If renewable energy and energy efficiency remain the only feasible options to reducing GHG emissions, established fossil fuel interests will likely remain opposed to significant reductions in GHG emissions, and will fight comprehensive carbon regulation efforts. To fossil fuel interests, the short-term costs of switching to renewable energy are perceived as worse than the long-run costs due to climate change, and thus they have fought climate regulations that would have generated huge net positive benefits to society (but not necessarily to these fossil interests).
If cost-effective CDR is available as a complement to renewable energy, however, burning fossil fuels no longer is mutually exclusive with meeting GHG emission reduction goals. This is because of the fact that, as long as fossil fuel emitters generate more CDR than GHG emissions, they can reduce their contributions to total atmospheric CO2 concentrations. The prolonged burning of fossil fuels might have other adverse consequences that we want to avoid, but CDR can help reduce the short-term costs of GHG emission mitigation to fossil fuel interests, potentially changing their political calculus to support climate change mitigation efforts.
3. Getting to zero GHG emissions might be really expensive, and CDR could help make emission reductions more affordable.
Many activities, such as long haul trucking and aviation, don't lend themselves to de-carbonized electrification well. As long as biofuels remain expensive, completely eliminating GHGs from these sectors will also be expensive. Developing affordable CDR solutions will provide yet another weapon in the arsenal to reduce GHG emissions without causing costs to skyrocket in industries most affected by climate regulations. Even if it turns out that we are able to reduce emissions quickly enough to mitigate climate change without going negative, CDR could play a significant part in helping to generate these emission reductions as cost effectively as possible.