Keeping Up with Catastrophe
On the complexity of tree coverage as a quick fix for climate change
When my eldest nephew was a wee sprog of seven, he confidently declared a theory of why some people have more than others, and it was a meritocratic view of the world bereft of nuance or any understanding of situational factors. So, as one does, I presented some thoughts that might complicate his initial position—then quickly realized that my nephew hadn’t been trying to engage in a discussion at all. He’d been trying to communicate to the adults all around him—adults all talking confidently from their own bodies of worldly intel—“I know things, too!” He was emulating our collective tone of authority, more than expressing any real interest in having his views explored, tested, and challenged in the middle of our broader debate.
At that age, even when a child wants to keep learning, and even when they keep asking wonderful questions to this end, they can also become exasperated once an adult starts giving them the answers they’d solicited. It’s a confusing mental energy, all this see-sawing between asking and getting defensive, but it relates to the child’s rising sensitivity to being talked down to—even when they might genuinely want to know what the adults around them think. Yes, they want to learn, but even more, they want to be seen as knowing things in turn. They’re not babies anymore, and they ache not to be on the receiving end of knowledge anymore.
So, my nephew was pretty sensitive at the mere possibility that his global theory of meritocracy might not be as ready for “prime time” as he thought.
But again, he was seven.
The problem arises when we adults struggle to do any better—when we bristle at the idea that our own, off-the-cuff opinions might not be fully formed, either. At our ages, we can also get exasperated when someone tries to tell us that what felt right on a gut level might in fact be more complex than we first thought.
And yet, one hard truth learned by (some) adults is that ignorance abounds among older generations, too. Most of us are carrying around a body of gut feelings that shape our most “well-reasoned” convictions, and we tend to bristle and “tribe up” the moment that any of these are met with worldly nuance. Children might not have access to as much data as the rest of us, but the rest of us aren’t that great at processing all the data we have access to, either—let alone at on-boarding new data over time.
If we’re not careful, too, we adults easily calcify in positions acquired at specific points in our development. We feel as though we already tested those points of view before, so why should we bother entertaining different possibilities now?
Adjusting our views to fit emerging evidence is especially difficult when those views are serving us well—and when new data would only make a hash of everything else.
In the case of climate change, for instance, there is a common refrain that we “just” need to do X if we want to repair the damage caused by industrial practices.
This is an excellent way to alleviate our lack of agency, by suggesting that the problem itself is simple: only will-power is lacking. Such an outlook lightens our personal load, and further indulges us in the belief that mitigating climate change won’t require much drastic action—“just” this one little trick—when we eventually get around to it.
For some, the “just” in this climate equation is switching out all fossil-fuel transport vehicles for electric. If we could just do that, what a difference it would make!
For others, “just” is a matter of taxation—if we could just fix corporate tax rates!—or maybe of bringing out the guillotines.
And in the “just” that I want to talk about today, it’s the trees.
If we just plant more trees, oh, what a world we might have again!
The allure of the natural fix
In late March, a paper published in Nature highlighted the complexity of using trees as a defense against climate change. Simply put, in some contexts tree coverage only contributes to overall planetary heating, so we can’t rely solely on the idea of natural carbon sinks to address our accelerating climate crisis.
But before we explore those findings, let’s take a beat to think about the feel-good nature of stories predicated on the promise of reforestation in general. We’ve been hoodwinked by plenty of them before, but our inner seven-year-old still loves the simple elegance of the idea that we can “just” patch up the problems of global warming by creating a few more carbon sinks. It’s an all-natural solution, too—and clearly value-neutral. What political group could possibly be against trees? Surely even countries that hate each other will come together around the value of foliage, no?
One of the strongest examples of this wishful thinking is the Great Green Wall, a Pan-Africa project we tend to adore because it invokes ideals of world peace and common purpose that we want to believe our climate crisis could finally inspire in us. Often misrepresented as involving a literal wall of forest across Africa, the project goes far beyond localized carbon sequestration and anti-desertification goals. The initiative more uniformly strives to improve the quality of degraded landscapes across participating countries, and to cultivate better agroforestry practices that can in turn enrich the socioeconomic and nutritional outcomes in each region.
But in that promise also lies the reason that the Great Green Wall is struggling in places: resource and related territorial warfare. In some participating countries, armed conflict drives citizens out before they can heal the land in full. Others aren’t as interested in an enriched landscape that might conflict with lucrative mining goals.
And of course, it doesn’t help that, for all the world’s grand promises of investment in this complex initiative, the actual funding situation for the Great Green Wall is inconsistent at best. As a report in Nature last April outlined:
A United Nations representative told Nature that donors have committed $15 billion to a pipeline of 150 projects. But a UN report published in February acknowledges that it’s not clear how much of this is grants, how much is loans and how much is existing funding relabelled as Great Green Wall money. Moreover, coordination between Great Green Wall countries and donors is weak.
The report suggests that trust between the African Union and international donors is in short supply. Donor nations seem to be picking and choosing which countries to invest in, with a preference for those in relatively stable regions. So Ethiopia, Eritrea, Niger and Senegal are among the most active participants (see ‘Off-target’). The less-involved countries — Chad, Mali, Burkina Faso and Sudan, for example — also happen to be the ones that are ruled by their armed forces, with instability, insurgencies and high rates of internal displacement, lost livelihoods and poverty as people flee fighting. The situation in Sudan has become particularly precarious, because military and paramilitary forces are now in open conflict. Conservation and economic-development projects are challenging to achieve in such conditions. The tragedy is that international donors seem to be pulling away (or moving only slowly) just when the people of these countries need their help the most.
Suffice it to say, some of the immediate impacts of climate change, especially in relation to resource wars, are significantly undermining our capacity to implement the long-term projects we need to launch now, if we’re to have any chance at all of easing even worse systemic pressures down the line.
It’s a race not just against time, but also against our desire to forfeit the race entirely.
Meanwhile, for years, we’ve been dealing with the false promise of carbon offsets as a magical fix for emissions from manufacturing, distribution, and travel. Last year, analysis of the world’s largest certifier found that 90% of rainforest carbon offsets are worthless: stemming from vague or unverifiable claims to protect land from deforestation in lieu of actually compensating for rising greenhouse gases. By the end of the year, more carbon offset projects had been brought to light as oversold in their efficacy, or outright scams. This February, US analysts further found that carbon removal was being exaggerated 2.6 times over the real impact of forestation initiatives.
We humans aren’t very good at processing this sort of complexity, though. A good analogy comes from diet culture, where some people are enamoured by the pleasing symmetry of “calories in, calories out” as a slogan—even though our bodies are not at all passive participants in this exchange: our metabolic rates are shaped by hormonal arrangements in routine flux, such that different environmental conditions impact how our bodies consume energy. As such, even though it’s technically true that weight management is all about how much you take in and how much you burn, the actual calculus of “burning calories” is more complex than simple numbers on a box let on.
So too, in the realm of climate studies, is the symmetry of “carbon emitted, carbon captured” deeply misleading. Technically it’s true, but we still have to look at the not-at-all-passive environment in which carbon capture is said to be taking place. Is it taking place where people say it is? Based on what models and measurements? Or is our world’s “metabolic rate” also a lot tetchier than many carbon reports let on?
The downside to tree coverage
Which brings us to the latest reminder that our inner seven-year-old doesn’t have all the answers; that our gut feeling about “natural” solutions isn’t always right; and that trees aren’t automatically a net positive in our struggle to mitigate the climate crisis.
Now, granted, the paper published this March in Nature isn’t our first exposure to the complexity of arboreal fixes. In 2019, another paper modelled the possible negative impact of nitrogen-fixing trees. In it, the authors suggested that the more such trees serve their primary function by enriching surrounding soil systems, the more they also undermine carbon sequestration benefits. A balance would thus need to be struck in future reforestation projects, to serve the nutritional and socioeconomic needs of local communities without exacerbating climate change pressures in the process.
But the problem presented in “Accounting for albedo change to identify climate-positive tree cover restoration” is also a doozy. Albedo is a measure of the amount of sunlight reflected back into the atmosphere by the surface of our planet. Although tree coverage provides a form of carbon sequestration through the natural respiratory processes of any floral ecosystem (i.e., carbon dioxide in, oxygen out), forests are also darker than plains and deserts, by pure coloration. And that darkness means that they will absorb more sunlight than other landscapes.
Which brings us to the core findings of this paper:
Previous efforts to quantify the global climate mitigation benefit of restoring tree cover have not accounted robustly for albedo given a lack of spatially explicit data. Here we produce maps that show that carbon-only estimates may be up to 81% too high. While dryland and boreal settings have especially severe albedo offsets, it is possible to find places that provide net-positive climate mitigation benefits in all biomes. We further find that on-the-ground projects are concentrated in these more climate-positive locations, but that the majority still face at least a 20% albedo offset.
You can see in the above writing that the authors framed their findings as positively as possible, but the inclusion of albedo into discussions on the role of afforestation as a means of combating climate change still presents a significant challenge.
Not that it’s better to stay in the dark, mind you!
But this latest analysis also highlights how much of our recent knowledge (as lay-persons especially) has been shaped around insufficient modelling. Specifically:
Although previous work has emphasized the importance of accounting for albedo change, albedo is either omitted from—or only coarsely modeled in—most assessments of the mitigation potential of restoring tree cover. Prior efforts have used latitudes or biome boundaries to eliminate potentially disadvantageous areas, or have applied uniform and arbitrary deductions to carbon accumulation in places where large albedo changes are expected. Some recent studies, using more sophisticated spatial methods, find that albedo change substantially offsets the climate benefit of restoring tree cover in Canada and of afforestation in global drylands. Albedo offsets are generally expected to be highest in locations with lots of sunlight, with consistent snow cover or other highly reflective land surfaces, as well as in places where trees have slow rates of carbon accumulation. However, changes in surface albedo with land cover change and subsequent climate effects, can vary substantially at local scales. Thus, spatially refined maps of these effects are needed to more fully characterize the climate implications of restoring tree cover across the landscape.
Is it frustrating to be reminded how little we “adults” ever know, and how poorly we’ve been designing our climate mitigation policies within these knowledge gaps?
Would life be a whole lot simpler if we could still confidently (ignorantly) declare that we just need to do X to fix the climate problems in our hurting world?
Absolutely, on both accounts.
But unlike the seven-year-old still striving to be heard at all, we adults—knowing full well how limited adult knowledge is—have no excuse not to learn to live in greater tension with a challenging array of new data as it arises.
The fact is, some of the most prominent ways of addressing climate change—like “just” planting trees—are currently undermined by an array of political and financial complications we haven’t the foggiest idea how to counteract; or else based on deceptive industry hype and incomplete representations of the full scientific picture.
And yet, we still have to keep trying to make them work—one muddled amendment of a data set at a time.
What other choice do we have?
Be well, be kind, and seek justice where you can.
ML