Science of Emissions

Scientific evidence that fossil fuel emissions need to be almost zero

"Stabilization of the climate system requires carbon dioxide emissions to be eventually eliminated."

--Andrew Weaver, IPCC Team Member, from Keeping Our Cool, p. 264 (2008)

"Only in the case of essentially complete elimination of emissions can the atmospheric concentration of CO2 ultimately be stabilized at a constant level.  All other cases of moderate CO2 emission reductions show increasing concentrations because of the characteristic exchange process associated with the cycling of carbon in the climate system."

--International Panel on Climate Change, IPCC (2007)


This quotation is excerpted from page 824 of the IPCC's fourth assessment report, Frequently Asked Question 10.3:   If Emissions of Greenhouse Gases are Reduced, How Quickly do Their Concentrations in the Atmosphere Decrease? 

Meehl, G.A., T.F. Stocker, W.D. Collins, P. Friedlingstein, A.T. Gaye, J.M. Gregory, A. Kitoh, R. Knutti, J.M. Murphy, A. Noda, S.C.B. Raper, I.G. Watterson, A.J. Weaver and Z.-C. Zhao, 2007: Global Climate Projections. In: Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change

D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M. Tignor and H.L. Miller (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.

"All (UVic climate modelling) simulations that have less than a 60% reduction in global emissions by 2050 eventually break the 2C warming this century  Particularly disturbing from a policy perspective is that even if emissions are eventually stabilized at 90% less than 2006 levels globally (1.1 billion tonnes of carbon emitted per year), the 2C threshold warming limit is eventually broken well before the year 2500."

--Andrew Weaver, IPCC Team Member, from Keeping Our Cool, p. 243 (2008)


Link Between Emissions and Atmospheric CO2

PNAS | Contributions to accelerating CO2 growth by economic activitiy, carbon intensity and the efficiency of natural sinks (Josep Canadell et al, 2007)

National Research Council  |  Climate Stabilization Targets  |  Fall 2010

Emissions, Concentrations, and Impacts over Decades and Millennia