Another line of argument for a catastrophic impact of climate change is in the rate of change of global temperatures and/or ocean acidification. In this post, I’m going to poke a bit at the rates of change in global temperature via ice core data. This step – from globally to particular Antarctic locations – is questionable and I’ll look closer to see if this is justified in a latter post. With that said, what do the ice cores hold ….?
The fact that the ice core records do not seem full of methane spikes due to high-latitude sources makes it seem like the real world is not as sensitive as we were able to set the model up to be. This is where my guess about a worst-case 1000 Gton from hydrates after 2000 Gton C from fossil fuels in the last paragraph comes from.
Much ado about methane (Real Climate, Archer, Jan 4, 2012)
This is a rather complex chart, but we can break it down pretty quickly.
We can use the range of potential fossil fuels CO2 emissions developed previously and plot the resulting temperature responses given the common range [2, 3, 4.5] of equilibrium climate sensitivities. Feedbacks are implicitly included in the ECS and do not need to be dealt with explicitly as long as they have been included in the models from which the ECS has been derived.
Estimating the probability distribution for equilibrium climate sensitivity with a Gamma distribution visually fitted to Meinshausen 2009 Fig 3a” (top). The gamma distribution for the 2 to 4.5C spread for equilibrium climate sensitivity has a cumulative 85% probability.
Improved estimates for the Proven and Optimistic scenarios using the BP Statistical Review of World Energy 2011 (xls) as fully as possible. The original source for the optimistic estimates remains opaque. They are both considerably lower than the ‘in-place’ estimates used in WGIII, as they should be. Recoverable reserves are only a fraction of in-place resources.