And then there is the issue of anthropogenic deforestation to create more agricultural land, which also generates further CO2 emissions. This has been the primary focus to date. “Up to now, attention has been focused on deforestation – the transformation of forests into agricultural land. But researchers found that the total area affected by forest degradation is much larger. Here, the forest as such remains, but its structure is altered, owing for example to increased fire frequency or the selective logging of specific types of trees. “Degradation probably leads to even greater loss of CO2 than wholesale deforestation does,” is Julia Pongratz’s comment on this hitherto underestimated process. Furthermore, degradation is also occurring in the temperate and boreal woods of Europe, not only in the carbon-rich rainforests of America, Asia and Africa. These practices have a negative impact on the ability of forests to store carbon. “We must pay much more attention to the permanence of natural carbon sinks. We only have to look at what is happening to the forests on our doorsteps, which have been battered by droughts in three of the last 10 years. We can no longer take their capacity as carbon sinks for granted.”
Indeed, according to a recent report, even the Amazonian rainforest is showing signs of losing its function as a carbon sink, and some parts of it are already emitting more CO2 than they absorb. “In the year 2020, the rate of deforestation in the Amazon Basin reached its highest level in the last 10 years,” Pongratz says, and the trend in South Asia is similar. “In both regions, exports of food and fiber cause an expansion of agricultural land, and unfortunately that affects rainforests, which are particularly rich in carbon,” she adds.
The role of exports also reveals a peculiarity in the political attribution of CO2 emissions. At the moment, the CO2 emitted as a result of the consumption in Europe of foodstuffs grown elsewhere – soybeans in Brazil, for example – appears on the producing country’s balance sheet. The working group around Julia Pongratz was instrumental in producing an article recently published in Science magazine demonstrating that, because of global trade, 27 percent of emissions from land use and forestry alone – not counting emissions from fossil fuels – are not attributed to those countries in which the products are consumed. “Some 40% of the emissions that are directly linked to consumption in Germany actually originate in other countries,” Pongratz says. If these emissions were accredited to the factor ‘consumption’ instead of ‘production’, the contribution to global warming attributable to Germany would increase. The same conclusion can be drawn when looking back in history: “The regions that bear most of the responsibility for climate change are the US and Europe – owing to their long history of industrialization – because the driving force behind global warming is the cumulative amount of carbon emissions.”