Through the Paris Agreement, countries have set the goal of achieving a balance of greenhouse gas emissions and sinks, which would likely involve reducing CO₂ emissions to zero and then net negative within a rapid timeframe. Historically, biospheric carbon sinks have mitigated climate change by taking up a large fraction of anthropogenic carbon emissions but anthropogenic CO₂ emissions decrease through mitigation, the strength of biospheric carbon sinks is expected to decrease as well. The timing of these sink responses to emissions reductions is a key component in the overall climate response to emissions reductions, and partially governs the timing of climate stabilization relative to net zero emissions. Here we explore ecosystem carbon flux dynamics in response to the mitigation of anthropogenic CO₂ emissions, by looking at the lags between emissions and biospheric fluxes, using Earth system models across a range of scenarios that transition to net zero and net negative emissions.