Abstract
<title>Abstract</title> <p>Carbon management and the assessment of Carbon Dioxide Removal (CDR) strategies in the circular economy require dynamic material flow analysis (dMFA) tools capable of tracking and forecasting the complex and circular system behavior of heterogeneous carbon flows, stocks, and process dynamics over time. To fill a gap in capable and accessible tools, we present bioDYM, a flexible and open source dMFA software. On the basis of the ODYM framework, bioDYM enables low-code system modeling through the combination of stocks, flows and processes calculated with a modular system solver. Originally focused on biogenic carbon systems, bioDYM has evolved into a fully functional general-purpose dMFA software. Custom-built process logics allow the modeling of specific carbon transformation pathways such as multipool first-order decay processes and dynamic stock modeling with Weibull lifetime distributions. A Monte Carlo engine propagates parametric uncertainty. A scenario engine enables scenario comparisons within a single simulation. Results are accessible through an interactive dashboard. We demonstrate bioDYM via a wheat straw carbon management case study (1,000 km², Germany, 2025–2125) and compare three application pathways: direct incorporation (DI), pyrolysis and incorporation (P&I) and use of construction material (CM). By 2125, the system removes 8,817 Gg C from the atmosphere, retained as stable biochar (P&I = 4,721 Gg C), long-lived construction products (CM = 3,687 Gg C) and decomposing soil organic carbon (DI = 409 Gg C). Monte Carlo analysis (n = 5,000) and scenario analysis prove the dominant influence of carbon stability and product lifetime on long-term CDR performance.</p>