This is highly disturbing. Keeping temperatures from increasing by more than 2°C requires the deep and rapid reduction of global emissions, so as to achieve stabilization at a relatively low concentration of greenhouse gasses. Using IPCC models, it can be estimated that the chances of avoiding a rise of over 2°C if atmospheric concentrations stabilize at 550 ppm are 15%. Even with stabilization at 450 ppm, the chances are only 50%. Stabilizing at 450 ppm would require that global emissions peak by 2010 and fall by 7% per year thereafter, falling to 70% below 2005 values by 2050. Stabilization scenarios with a lower probability of exceeding the 2°C require even more rapid cuts. The climatic effect of emissions reductions is the product of both their depth and their duration; delaying the timing of emissions reductions significantly increases the depth they must have, in order to produce the same climatic outcome.

a sibilant intake of breath