Carbon dioxide removal is an important part of net-zero scenarios, and is used to neutralize residual emissions of CO2. However, it only completely counterbalances the climate effects of CO2 emissions if it happens at the same time as emissions and keeps carbon out of the atmosphere as long as emissions would remain in the atmosphere. Today a number of carbon dioxide removal approaches take awhile to fully remove carbon from the atmosphere, and in some cases may even move emissions forward in time. Accounting for these lags in carbon removal is key to make credible claims, and we propose a framework for carbon markets to use to address these issues in the future.