Forests, Vegetation, Biomass: More Effects Of Agriculture On Climate
Though we often talk about environmental degradation in terms of deforestation, vegetation in general is important to consider. Vegetation contains a significant amount of the planet’s carbon stocks, and shifts in these levels play a key role in the global climate. When deforestation occurs, to use a common example, large concentrations of carbon dioxide are released into the atmosphere, contributing to climate change and other negative effects.
Deforestation has been acknowledged by the Land Sector report of the United Nations Framework Convention on Climate Change as a significant variable in the worldwide commitment to limiting global warming to below 1.5 degrees Celsius. Land-managed vegetation, on the other hand, doesn’t receive the same recognition, yet it potentially represents 42% to 47% of the carbon stored in vegetation biomass.
The carbon stocks of global vegetation have, up to this point, been poorly measured. Aboveground biomass stocks may be straightforward to measure, but estimating vegetation biomass carbon stocks on a global scale would be time-consuming, costly, and unreliable. New, state-of-the-art datasets have allowed scientists to theorize that vegetation currently stores about 450 petagrams of carbon.
Without any land use by humans, this number would hypothetically jump up to 916 petagrams of carbon stocks for vegetation. In other words, the data shows that over half of the global carbon stocks in vegetation have already been released into the atmosphere with land-cover changes. Deforestation accounts for the bulk — but not all — of this change. The rest is caused by land management effects on vegetation, which were previously underestimated in literature. This suggests that land management of current vegetation is far more important than once believed.
Worldwide, the biggest difference in biomass between potential and actual carbon stocks comes from agriculture. In other words, the majority of our potential vegetation biomass is wasted on producing animal products. Tropical rainforests and subtropical vegetation have the largest stores of carbon, while temperate and boreal forests hold about half the amount. This puts extra pressure on certain regions around the world, such as Brazil and South America more broadly, to severely reduce their levels of deforestation for agriculture.
In a hypothetical scenario, if we managed vegetation to reach its highest potential in carbon absorption by eliminating all agriculture-related human land use, we would be able to store the next 50 years of emissions in our forests, assuming carbon emissions continue at the same rate. While it’s a nice thought experiment, it’s probably unfeasible.
Other attempts to minimize agricultural land use, such as through a vegan diet, would allow us to (theoretically) restore vegetation that allows us to store more carbon. Other ideas include enacting severe reductions in wood harvests and restoring current wood harvest vegetation to 90% of its biomass. This would allow complete absorption of fossil fuel emissions for the next 7 to 12 years.
The authors of the study noted that a significant threat to biomass-stock conservation comes from Africa, where forests and savannahs have been identified as potential land for human agriculture to meet the global demand for meat and animal products. This shows that the problem is a worldwide one and requires a global balance between political and economic responses to address it.
The authors note that future research should delve more deeply into land management of existing carbon stocks, which are often not properly quantified in global studies. For animal advocates, the study shows that environmentalism and animal advocacy are more intertwined than we may realize. The data from this study, and from so many others, shows that animal agriculture has devastating effects on the climate, and that steering our food choices in another direction may be a key part of addressing the problem.