In the last two years, our scientific understanding of business-as-usual projections for global warming has changed dramatically (see “M.I.T. doubles its projection of global warming by 2100 to 5.1°C” and “Hadley Center projects 5-7°C warming by 2100“). Yet, much of the U.S. public — especially conservatives — remain in the dark about just how dire the situation is (see “Gallup poll shows catastrophic failure of media, conservatives still easily duped by deniers“).
Why? Because the U.S. media is largely ignoring the story. Case in point: Where was the coverage of the Copenhagen Climate Science Congress, attended by 2000 scientists, which concluded with this Key Message #1:
Recent observations confirm that, given high rates of observed emissions, the worst-case IPCC scenario trajectories (or even worse) are being realized. For many key parameters, the climate system is already moving beyond the patterns of natural variability within which our society and economy have developed and thrived. These parameters include global mean surface temperature, sea-level rise, ocean and ice sheet dynamics, ocean acidification, and extreme climatic events. There is a significant risk that many of the trends will accelerate, leading to an increasing risk of abrupt or irreversible climatic shifts.
What is the worst-case IPCC scenario trajectory? That would be A1F1 (the red dotted line in the figure below from figure SPM-3 of the 2001 Intergovernmental Panel on Climate Change, Synthesis Report):
The A1F1 scenario takes us to atmospheric concentrations of carbon dioxide of 1000 ppm in 2100 — otherwise known as the end of human civilization as we have known it. Actually it’s worse than that. The 2001 IPCC report largely failed to model amplifying carbon cycle feedbacks. The 2007 IPCC report, which began to consider such feedbacks, warns that even averaging 11 GtC (billion metric tons of carbon) a year this century could take us to 1000 ppm (see “Nature publishes my climate analysis and solution“). The A1F1 scenario averages well above 15 GtC a year through 2100 as you can see from the figure on the left.
Energy Daily (subs. req’d) notes of the U.S. media non-coverage of Copenhagen: