Bruce C. Cohen

An econometric time-series analysis of global CO2 concentrations and emissions

This paper extends previous work on the econometric modelling of CO2 concentrations and emissions. The importance of such work rests in the fact that models of the Cohen-Labys variety represent the only alternative to scientific or physical models of CO2 accumulations whose parameters are inferred rather than estimated. The stimulation for this study derives from the recent discovery of oscillations and cycles in the net biospheric flux of CO2. A variety of time series tests is thus used to search for the presence of normality, stationarity, cyclicality and stochastic processes in global CO2 emissions and concentrations series. Given the evidence for cyclicality of a short-run nature in the spectra of these series, both structural time series and error correction models are applied to confirm the frequency and amplitude of these cycles. Our results suggest new possibilities for determining equilibrium levels of CO2 concentrations and subsequently revising stabilisation policies.

Note: carbon-cycle estimation: a plea for measurement of ocean carbon dioxide concentrations

Unless an effort is made to measure the carbon dioxide content of the oceans, the ability of researchers to distinguish between absorption by oceanic and by biotic sinks related to carbon emissions will remain imperfect. This uncertainty presently limits the ability of policy-makers to set a carbon emissions target fully consistent with that for carbon dioxide concentrations.

Note: the Kyoto instruments: are they adequate for achieving the stabilisation of carbon dioxide concentrations?

It is argued that reaching stabilisation of carbon dioxide concentrations will require new policy instruments. The Kyoto instruments, while they serve to begin the process of emissions reductions, are only a first step in a process that will span many decades at a minimum. The new instruments should be directly aimed at R&D for developing the new non-carbon sources of energy.