Geographer and environmental scientist Eric Lambin sat down with Stanford Woods Institute for the Environment Director Chris Field to talk about his work in land use science. Lambin researches land use challenges and impacts, globalization, and sustainability. He splits his time between Stanford, where he is the George and Setsuko Ishiyama Provostial Professor and a senior fellow at Woods, and Université catholique de Louvain. He was chair of the international scientific project Land Use and Land Cover Change (LUCC) from 1999 to 2005 and is a foreign associate at the U.S. National Academy of Sciences.
Edited excerpts and video of the Feb. 19, 2020 conversation are below.
I think we are really on two tracks. Globally, of course, we are really damaging the system’s full capacity, and we develop a lot of local solutions: surface greening, campuses like this one, greening cities, trying to reconnect people with nature at very local places. It’s hard to operate at a much larger scale, hard to upscale all these small solutions that we’ve been testing and piloting in many ways. Reforestation is one solution. It’s become very popular over the last couple of years. It started as developing nature-climate solutions, so ways to mitigate that change not through technology but by using nature and trees to absorb some carbon from the atmosphere, soil to sequester some amount of carbon. But of course when you do the math, even just back-of-the-envelope calculations, if you evaluate the amount of reforestation that we require to have a significant impact on the climate then suddenly you enter into massive tradeoffs with food production or other ways of using land. That’s one of key goals of land use science is just trying to quantify how to fit all these land uses on the limited surface we have and provide all these services.
A: We started systematically studying each of these reforestation economies and we found that all of them, with no exception, as they were protecting their forests, they were also increasing their import of either food or timber, in different ways. And overall, that was more or less equivalent to 50% of the reforestation, so it’s really a glass half-full and half-empty. Half-empty because while they are protecting their territories it’s just being offshored abroad, and half-full because actually half of the forests are not being offshored and this results in more efficiency of land use.
A: Well that’s where it gets interesting actually, because not always. Initially my assumption was that this offshoring was a bad thing, you just push your deforestation elsewhere, and that’s sort of the case with Cambodia and Laos. But as we get studying that, we studied Bhutan, this small interlying kingdom with a very very crude economy, and even there they’re offshoring their land use elsewhere. But they were importing most of their timber from India and that timber was coming from tree plantations that are very well managed, while in Bhutan you have these very rich biodiverse forests. So we see timber coming from India rather than from the forest in Bhutan, so in that case, from an ecological view point, it’s a good thing. And that’s of course what ecology does and what we’re trying to do. But often this calculation misses the social and the ecological impacts of some of this offshoring.
A: I think it’s great to have these ambitious targets. They help to focus attention and focus efforts. Of course, if you do plan for a trillion trees, the question is which species in which locations. How are they going to compete? Will they survive? Do they compete against other land uses? What will be their impact on biodiversity? Are they mostly exotic species? Again, with these kind of approaches, I’d be wary of small solutions. When you try to upscale them, that’s when you have to think very deeply about what they mean at the global scale.
A: Yes, well, when writing about land use, it’s a very vast field, and a lot of literature is quite specialized. Someone worked on forests, another one on feed plantations, someone else on tropical fires, on cropland, on biofuels, but there are very few attempts to bring all these attentions together. But in the end they all have to fit on the amount of land we have on our planet. And so at one point we did an exercise through a workshop and we just brought all the specialists around the table to try to estimate what are the most likely figures of how much land is in these different land uses and what are the projections. And as we did that, some people realized, you know actually, we don’t have that much surface land. We don’t have so much spare land that we can assume can be used. And of course if you just look at biofuels, yes there will be plenty of land. But if you look at biofuels plus more tree planting, plus more cropland because the population is expanding, that’s how you realize that they’re all trying to use this productive land. And that’s when you realize that there will be a crunch time at some point and we’ll have to be much more efficient in the way we use our land. That’s when you realize that this concept of nature planet solution can at best help imagine the goal. Really 95-98% of the solution is going to have to come from less emissions from urbanization, industry, and transportation. And of course tree plantation, better land management, better soil management to save some carbon can help save some time and remove the emissions, but frankly there is no prospect that most of the problem will be resolved through tree plantation or other means. We plant trees, it’s better for the landscape, it’s good for the climate, it helps biodiversity. It’s great that we still get enthusiastic about solutions, but at some point we need some reality checks and we need to make sure that people don’t lose sight of what the real challenge is with emissions.