Why carbon might tell us less than we think

From the gases emitted through a car’s tailpipe to the tree biomass stored in the Amazon, carbon is no doubt the leading indicator of climate change today. But does a ton of carbon emitted by an aircraft 10 kilometers above the North Atlantic really equate to a ton of carbon stored in a mangrove forest in Indonesia – and, more importantly, can one really be ‘offset’ by another?

These were the loaded questions that the Global Landscapes Forum put to three experts on climate change solutions in a digital panel discussion on 5 June, sparking a lively debate on the merits and drawbacks of measuring ecological costs and benefits purely in terms of carbon.

One major point of contention was the arbitrary nature of carbon as a unit of measurement – and, most controversially, as a medium of exchange through international carbon markets, where carbon emissions in one part of the world can be compensated for elsewhere. “It’s very important to remember that carbon is a global abstraction,” stressed Camila Moreno, a researcher at the Federal Rural University of Rio de Janeiro. “We rely on digital infrastructure to commodify and to measure something that is intangible: a carbon unit.”

These carbon units, while useful for reducing net emissions at a global scale, can also create imbalances between different parts of the world, Moreno argued. “Regions of the world have different mitigation potentials because photosynthesis happens very differently in the Amazon and in Siberia. So some areas of this planet are going to be more cost-effective to decarbonize than others. But you cannot compensate in Papua New Guinea for a problem in the Amazon.”

While arbitrary, carbon units still serve as a valuable ‘common currency’ for making comparisons, according to Jürgen Bauhus, head of the Department of Silviculture at the University of Freiburg. Instead, he takes issue with a “single-minded focus on carbon” in the forestry sphere that he believes has caused other functions, such as biodiversity and hydrological cycles, to be overlooked. “By simply focusing on one goal, we will never optimize the delivery of the wide spectrum of ecosystem services that we want to obtain,” he emphasized.

Bauhus also pointed out an inherent trade-off between planting trees to mitigate climate change and allowing forests to adapt to a warming world. In Germany, for instance, afforestation efforts have been so focused on maximizing carbon sequestration that other tree species – particularly light-demanding species that are better adapted to the warmer climate of the future – have been crowded out. “If we continue to increase our carbon stocks, we will have large problems adapting the forests to future conditions and providing a variety of ecosystem services,” he said.

Echoing Bauhus’ thoughts was Nathalie Seddon, director of the Nature-based Solutions Initiative, who highlighted the importance of ensuring forests are resilient through species diversity. “We really have to avoid scaling up afforestation with single species and with non-native species,” she opined. “These are very low in resilience, and they risk compromising local land rights.”

Seddon also warned against being overly fixated on forests and neglecting other valuable ecosystems, such as mangroves, peatlands and grasslands. “In some parts of the world, these ecosystems may be more resilient than forests,” she noted, adding that they also play an important role in preserving biodiversity. Most crucially, she made clear that carbon storage cannot replace the need to reduce society’s reliance on fossil fuels. “Natural climate solutions are not an alternative; they’re a complement.”

Both research and policy, Seddon believes, should focus on designing targets and indicators that can maximize ecosystem resilience. “We need to think about diversity, connectivity, heterogeneity in landscapes,” she said. “The only thing we can be certain about in the future is increasing uncertainty, and in that context, it just makes a great deal of sense to invest in careful, locally-implemented ecosystem stewardship.”

While all three panelists expressed misgivings with a potentially excessive focus on carbon in the policy realm, the question of how to integrate it into a holistic strategy to combat climate change also proved controversial. Bauhus believes there is no shortage of well-designed policies that simply need to be brought together: “In Germany, we’re in the process of revising a national forest strategy, which includes the climate protection plan, the biodiversity strategy and the bioeconomy strategy and asks: how can we reconcile them?”

Moreno, however, pointed out that current policies rely heavily on technologies with availability largely limited to industrialized countries due to their costs. “If the climate crisis were such a crisis, there would be no patents,” she argued. “Technological packages would be immediately distributed for free. But that’s not what we see. We see more debt, more laws and more dependency being imposed in the Global South to acquire a technological package.”

Instead of using sophisticated mechanisms to store and exchange carbon, she suggested that there can be no alternative to simply cutting emissions by reducing consumption. “We keep promoting low-carbon agriculture and solutions coming out of BASF and Syngenta,” she said.

“But we never question slowing down trade to massively reverse the level of consumption that is being spread all over the world as a universal right.”