Seems to me like if we take these conclusions at face value, it should set us in motion defending our cities, and planning for living on a warmer planet.
I’m somewhat skeptical of some of the science. I’m the only person I know who’s read IPCC AR5 cover to cover. While I’m not explicitly a climate scientist, I do have a master’s degree in environmental fluid mechanics, have graduate schooling in physical meteorology, and I’m a practicing professional hydrologist and civil engineer. I think the entire dialog about climate science in the public sphere is flawed, because it’s been funneled into binary thinking by punditry.
There’s a long argument chain, and each link in the chain needs to be looked at. The chain goes like this:
The globe is warming >
The warming is primarily due to CO2 >
The warming is entirely due to CO2 >
The CO2 is anthropogenic >
No other anthropogenic factors are significantly warming the globe >
We can arrest global warming by adjusting anthropogenic carbon >
This adjustment of anthropogenic carbon is achievable >
(Policy X) will arrest global warming.
Some of these things I find to be obviously true, and some of them I find to be obviously false, but pointing out the obviously false things gets me labeled a “climate denier” or such, because of the binary thinking in the body politic.
I think that the effects of global land use change are very poorly studied, compared to the CO2 effects. I think the urban heat island phenomena is only one aspect of a larger albedo issue that’s not being studied properly. When AR5 indicates that deforesting half the world’s old growth forests in the last 100 years provided a net cooling effect, I find that to be very suspicious. When they admit they have very poor models of how increased cloud cover due to global warming (more heat = more convection = more clouds) will impact the albedo terms, I think that dampening effect may be very important to understand better before we jump off a cliff.
I also think it’s frustrating that IPCC AR5 set the mean climate sensitivity due to anthropogenic carbon (the most important number in the entire document) to somewhere between 1d C per doubling and 7d C per doubling. That’s an incredibly wide range. It’s like your doctor saying “you are currently in cardiac arrest, or possibly ate some bad cheese.” I’d want a second opinion. And in each IPCC report their estimates of this number get wider instead of smaller. You’d think with more science we’d be zooming in to the correct number, not becoming less certain of it.
I’m not anti-science at all, but I think the science needs to get a lot better, a lot faster.
My intuition tells me that anthropogenic global warming may only be perhaps 2/3rds due to carbon, and is likely 1/3rd due to other stuff related to land development and mechanized agriculture. My intuition further tells me that we could probably make a lot more hay with a massive reforestation campaign than we could building CO2 internment factories. When you run the numbers on conservation, you find that literally buying rainforests and preserving them is far more cost effective than any other end-of-pipe carbon reduction strategy. That’s the lowest hanging fruit, and we’re not even picking it.
And when the “12 years to doomsday” estimates come out, the simple truth is that that’s stating we’ve already fallen off the cliff. The only way to make substantive changes to CO2 emissions inside a 12 year window is a global deadly disease outbreak or thermonuclear war. That’s not a cost-benefit analysis I’m willing to engage in.
I think the solutions we’re being steered towards are flawed, because the public dialog is flawed. I think the media flaws it on purpose to push clicks.
Just some thoughts.