The Terrestrial Carbon Sink
We review recent developments and the current state of knowledge on the terrestrial carbon sink. We start by giving an overview of the terminology used to refer to different aspects of the terrestrial carbon cycle and present the fundamental principles that characterize carbon cycling in terrestrial ecosystems. We then examine recent developments in our knowledge of how carbon cycles through different ecosystems and the tools used. Finally, we conclude with a discussion of the policy implications of a terrestrial carbon sink.
The continuation of the global carbon sink is essential in order to achieve climate mitigation targets. This review highlights key areas when more understanding is needed in order to provide policy-actionable projections of the terrestrial carbon sink under future climates. In particular, advances in infrastructure that allows a more seamless interface between models and observations are highlighted as a key priority for future research efforts.
Life on Earth comes in many forms, but all life-forms share a common element in carbon. It is the basic building block of biology, and by trapping radiation it also plays an important role in maintaining the Earth’s atmosphere at a temperature hospitable to life. Like all matter, carbon can neither be created nor destroyed, but instead is continuously exchanged between ecosystems and the environment through a complex combination of physics and biology. In recent decades, these exchanges have led to an increased accumulation of carbon on the land surface: the terrestrial carbon sink. Over the past 10 years (2007–2016) the sink has removed an estimated 3.61 Pg C year−1 from the atmosphere, which amounts to 33.7% of total anthropogenic emissions from industrial activity and land-use change. This sink constitutes a valuable ecosystem service, which has significantly slowed the rate of climate change. Here, we review current understanding of the underlying biological processes that govern the terrestrial carbon sink and their dependence on climate, atmospheric composition, and human interventions.