Verifying Greenhouse Gas Emissions

Trust in an international agreement to limit future greenhouse gas emissions will depend on the ability of each nation to make accurate estimates of its own emissions, monitor their changes over time, and verify one another’s estimates with independent information. A recent National Research Council committee assessed current capabilities for estimating and verifying emissions from greenhouse gases that result from human activities, have long lifetimes in the atmosphere, and are likely to be included in an international agreements. These include CO2, CH4, N2O, HFCs, PFCs, SF6, and CFCs. The analysis shows that countries have the capability to estimate their CO2 emissions from fossil-fuel use with sufficient accuracy to support monitoring of an international treaty, but accurate methods are not universally applied and the estimates cannot be checked against independent data. Deployment of existing methods and technologies could, within 5 years, yield a capability to both estimate and verify CO2 emissions from fossil-fuel use and deforestation, which comprise approximately three-quarters of greenhouse emissions likely covered by a treaty. Estimates of emissions of other greenhouse gases will remain uncertain in the near term.