Working into overtime, COP26 negotiators hatched an agreement that pleased some and disappointed many. Before summarizing the positives and negatives (next blog post), I want to review how we might reduce concentrations of greenhouse gases in the future. What CAN we do? An understanding of these options is important to understanding what the new agreement might mean. There’s also a great deal of confusion about what might help and how much.
Like the science underlying the physical basis of climate change, the science of solutions has also come a long way recently. Some solutions that were highly touted as recently as 2-3 years ago are now in question, as an example. Let’s start with a taxonomy of four types of solutions to control future atmospheric greenhouse gas concentrations.
(1) We can reduce our overall consumption…of everything. Some of this could be from higher efficiency of production and use, and some from discouraging our global hunger for more of everything. We could drive less, buy less, heat less, etc. This is a huge topic that is critical, but the solutions are diffuse and beyond what I can cover here.
(2) Even without (1), we could cut our emissions, mainly by replacing fossil fuel burning with renewable energy, but also halting deforestation (which releases gases).
(3) We can promote “nature-based solutions” to take up more carbon dioxide from the air and store it on land (or water). So, plant more trees and protect forest or other ecosystems that take up CO2 through photosynthesis and store it. Nature-based solutions also include improving soils through better agriculture (often called regenerative agriculture), so that they can take up more CO2 from the air and sequester it in the soil. There are other ways that we can invest in mechanisms by which nature can help by taking and storing CO2, but I’ll leave it at that for now.
(4) We can find non-nature-based ways to remove CO2 from the air. We’re mainly talking about industrial plants that remove CO2 from the air. Because (3) and (4) both seek to remove CO2 from the air, they are similar, but I think it’s convenient to keep them separate, as you will see soon.
So, where are we with solutions in 2-4? Let’s take them one by one.
(2) CUTTING EMISSIONS includes renewable ways of generating electricity, heat, etc. Solar power, wind power, hydropower, etc. . Many are widely supported (e.g., solar), whereas others are controversial (e.g., nuclear). As most of you know, many of these renewable technologies are very well developed and are growing rapidly. There are also combinations of technologies that have great promise. For example, shifting to all electrical vehicles, with electricity supplied by solar energy. The central idea of international efforts at controlling climate change is for countries to transition from fossil fuel based energy to these renewable strategies. No energy generating technology is completely environmentally benign, and you will read criticisms of all of these. It will be crucial for us to figure out how to minimize these negative impacts, while progressively improving their capacity, efficiency, and affordability. One other issue: although some of these technologies have become much more affordable recently, upfront costs will be expensive for countries transitioning from fossil fuel to clean energy. A key issue at COP26, in fact, was aid from rich countries (with a long history of filling the atmosphere with CO2) to less developed ones to help with this crucial shift.
There’s a special category to mention here: biomass. A decade or more ago, burning wood for electricity or heat was seen as an amazing solution for reducing CO2 emissions. Burning wood might release CO2, but when you remove a tree from the forest, so the argument went, the forest will respond by growing a new tree that will take up CO2 anew by photosynthesis, making up for those emissions from biomass burning. This would be called “carbon neutral.” Much better analyses (and thinking) have revealed that usually this is just not the case. There are special cases (regions, types of trees, types of management, etc. where it might make sense. At my own university, we heat part of the campus via a biomass plant that burns local, sustainability harvested wood (chipped), trucked over short distances. The plant employs local people and much of the money circulates in the local economy, avoiding purchases of fossil fuels purchased from far away. We haven’t done a life cycle analysis of the plant in terms of energy and climate emissions, but this is an example of biomass that might make sense as a transition to an even more environmentally benign approach in the long run. Main point, however, biomass burning for energy is probably very rarely carbon neutral, and, over the long run, there will be better large-scale solutions to the climate crisis. This is a serious issue worth raising in part because many still promote biomass as a completely carbon-neutral solution.
(3) NATURE-BASED SOLUTIONS are complex, and there have been vigorous debates about them. Let me discuss just two here.
First, a paper in a scientific journal argued in 2019 that planting 1 trillion trees could make a huge dent in the climate problem by taking up ooodles and oodles (not a technical term, but hey, you know what I mean) of CO2 from the air as they photosynthesized. There was rapid science pushback in the form of five articles that revealed that serious errors in the original article. It’s not trees couldn’t help, but not nearly to the extent argued in the original paper. Nevertheless, the article started the “Trillion Tree” project around the world. Many people and countries jumped on the bandwagon, with the idea that here was a painless, feel good, feasible way to reduce CO2 in the atmosphere. Analyses in the past 2-3 years have produced disappointing appraisals of planting our way out of the problem. Some tree planting was in the form of harmful plantations, some trees were poorly cared for, some replaced habitat that does just fine at taking up carbon. An analysis of India’s efforts over a longer period of tine revealed very little benefit. This doesn’t mean that planting trees in the right way, in the right place can’t help fight climate change, as well as providing other ecological and local community benefits. But tree planting does not appear to be a magic bullet in our fight against climate change.
Briefly — because I’m already running long — some have argued that actually protecting current forests, restoring entire ecosystems, and allowing forests to become old growth has lots of potential for removing some CO2 out of the air, as well as protecting biodiversity and providing benefits to local communities.
Second, “regenerative agriculture” and it’s capacity to restore soils and store carbon in soils has become the new, popular kid on the climate solution block. Let me be clear: pretty much all the evidence I’m aware of conclusively shows that better agricultural practices can greatly improve the soil and its productivity and resilience to climate shocks. But soil scientists are split about it promise for substantially helping with climate change.
For both of the examples here on nature-based solutions, three points emerge. There are disagreements among scientists, the devil is in the details, and, with the exception of planting the wrong thing in the wrong way in the wrong place, most of these efforts should be strongly supported because their overall benefits can be enormous. In fact, I think that one of the attractions of nature-based solutions to climate change all along has been their many aside benefits to nature, including people.
(4) It’s pretty exciting that the first true CO2 REMOVAL plant just starting its engine (wrong metaphor, perhaps) in Iceland. It take CO2 out of the air, stores it in rocks, and buries these permanently deep in the ground. As exciting as this is, this first plant removes a minuscule amount of carbon from the air. There are others planned for the this decade that promise to greatly upscale carbon removal, but even these will not make a dent in the CO2 problem. It is possible that these technologies will take off in the future and initiate a CO2 draw-down era. And I am not at all opposed to efforts to try (why would I be…but see below). But it is crystal clear that we can not count in carbon removal to save us, at least not any time soon. And we don’t have time to wait around to see how this turns out.
So, there’s my very skeletal taxonomy of solving the climate crisis, at least the mitigation part of it. (Mitigation refers to stopping climate change; adaptation to dealing with the consequences.)
Where does this leave us? I think it becomes apparent why so many climate activities are demanding that people, businesses, and countries reduce consumption, phase out fossil fuels, adopt renewable technologies, and drastically cut emissions. Nature-based solutions should continue to receive support, and we should investigate carbon removal at larger scales. But we can’t let these efforts distract us from our chief set of solutions: cutting emissions. Many corporations and countries have used nature-based solutions as “offsets” so that they can continue to emit huge amounts of greenhouse gases. That’s been one of the hot topics at COP26: how to ensure honest accounting of emissions and nature-based solutions.
BOTTOM LINE:
CUT EMISSIONS,
IMPLEMENT NATURE-BASED SOLUTIONS REGARDLESS OF THEIR CLIMATE BENEFITS,
INVESTIGATE CARBON REMOVAL.
The World is On Fire 
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