As the effects of global warming become more apparent, the growing consensus is that our remaining window to address this crisis is short. Perhaps as short as eleven years to significantly reduce our emissions and avoid the worst, according to the Global Carbon Budget. Or even as few as eight years, which the Intergovernmental Panel on Climate Change projects to be the time we have to cut global emissions by 43% to keep warming below 1.5C.
How methane is different from CO2
We must act fast, and that means we must measure the impact of our methane emissions mitigation efforts along similarly short timescales. But how short? It turns out that this can be a bit complicated when it comes to methane because its greenhouse effect changes over its lifetime in the atmosphere. When first emitted, methane is very potent: measured over 20 years one methane molecule drives the same amount of warming as 85 carbon dioxide molecules! But over the decades it breaks down, so when measured over 100 years one methane molecule has 30 times the global warming impact as one carbon dioxide molecule.
Why 20-year timeline makes sense
Stated clearly, we don’t have 100 years to address this crisis. So to measure the global warming impact of methane emissions reductions resulting from our surveys, Kairos is moving to use a 20-year time horizon. This also provides a more physically realistic model because the constant global emission of methane maintains high potency in the atmosphere. We use this same time frame to calculate the equivalent number of cars or coal-fired power plants that would need to be eliminated to have the same climate impact as our methane emissions reductions. We believe that we can reach our climate goals. But as the science shows, we simply have to do it within the next 20 years or sooner!
 Friedlingstein, P., et al., 2021. Global Carbon Budget 2021 (preprint). Energy and Emissions. https://doi.org/10.5194/essd-2021-386
 IPCC, 2022: Climate Change 2022: Mitigation of Climate Change. Contribution of Working Group III to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [P.R. Shukla, J. Skea, R. Slade, A. Al Khourdajie, R. van Diemen, D. McCollum, M. Pathak, S. Some, P. Vyas, R. Fradera, M. Belkacemi, A. Hasija, G. Lisboa, S. Luz, J. Malley, (eds.)]. Cambridge University Press, Cambridge, UK and New York, NY, USA. doi: 10.1017/9781009157926
 IPCC AR5. 2013 Anthropogenic and Natural Radiative Forcing. In Climate Change 2013: ThePhysical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (eds TF Stockeret al.). Cambridge, UK andNew York, NY: Cambridge University Press
 Kleinberg, R.L.; The Global Warming Potential Misrepresents the Physics of Global Warming Thereby Misleading Policy Makers; http://eartharxiv.org/repository/view/1686/