A former professor of ecology, Guy McPherson has attained some fame and respect among back-to-the-land “permaculture” types. I have no idea what he may or may not know about ecology, but he doesn’t know much about climate. This hasn’t prevented him from using his professorial credentials in the “permie” subculture, and what he tells the permies is that we are absolutely, irrevocably doomed.
Specifically, he believes that there are unstoppable feedbacks built into the climate system that have now triggered the system into instability. He thinks the climate will go bonkers in the way Jimi Hendrix’s guitar would howl when he held it up to the amp speaker. And he thinks it will go so thoroughly out of kilter as to kill every human alive by 2030.
It’s hard to tell why, but some people love him for it. It seems to me he is doing a lot of damage with this schtick nonetheless.
And what do you think of him yourself, Biff?
One bit (of several...) he talks about that I don't understand is how CO2 takes 40 years to have its effects on global warming. Is it true? Can you explain how in simple terms?
It's not true. CO2 starts affecting the climate straight away. I am guessing that what he's talking about is the length of time it takes for CO2 to disappear, compared to methane. Additional CO2 hangs around for 80-100 years, so the 40 year figure may be half of 80 years. It's the centre of the period that CO2 affects the climate, so perhaps he's talking about how long it takes to have its full effect...sort of.
I experience pleasure and pains, and pursue goals in service of them, so I cannot reasonably deny the right of other sentient agents to do the same - Steven Pinker
No that's not right. CO2 hangs around for centuries, but it takes thirty years for the earths temperature to rise into equilibrium with the current concentration in the atmosphere. CO2 starts trapping HEAT as soon as it is released, but the thermal capacity of the oceans in particular is huge.
emordnilap wrote:
One bit (of several...) he talks about that I don't understand is how CO2 takes 40 years to have its effects on global warming. Is it true? Can you explain how in simple terms?
Nope, I can't explain that. CO2 has a roughly linear effect on warming so any increase will have an immediate effect. I haven't read much of his stuff as I tend to stop at the first nonsensical sentence. There's enough good writing on the internet so don't bother with junk.
Thanks for the confusion guys. Ralph, that sounds plausible too.
I experience pleasure and pains, and pursue goals in service of them, so I cannot reasonably deny the right of other sentient agents to do the same - Steven Pinker
So, Ralph, would you go along with the assertion that it's only now we're experiencing the effects of emissions from the 70s/80s? That "we ain't seen nuttin' yet"?
I experience pleasure and pains, and pursue goals in service of them, so I cannot reasonably deny the right of other sentient agents to do the same - Steven Pinker
emordnilap wrote:So, Ralph, would you go along with the assertion that it's only now we're experiencing the effects of emissions from the 70s/80s? That "we ain't seen nuttin' yet"?
It's not quite that simple, as Ralph said. Theoretically today's carbon emissions have an effect tonight, warming things up but equilibrium is not reached for a long time so we are still catching up with the 70s/80s emissions. CO2 leaves the atmosphere by dissolving in sea water up to the point where equilibrium is re-established. Thereafter the CO2 hangs about in the atmosphere for more or less ever. Very slowly it combines with the calcium in silicate rocks as mountains are weathered but we're talking a time-scale of a million years here.
So CO2 is modelled as a 'stock' pollutant. If you emit it, you have to live with it forever. Compare and contrast with black carbon, which is a powerful component of climate forcing right now, but if we were to stop burning stuff it would mostly wash out in the next shower of rain.
emordnilap wrote:So, Ralph, would you go along with the assertion that it's only now we're experiencing the effects of emissions from the 70s/80s? That "we ain't seen nuttin' yet"?
It's not quite that simple, as Ralph said. Theoretically today's carbon emissions have an effect tonight, warming things up but equilibrium is not reached for a long time so we are still catching up with the 70s/80s emissions. CO2 leaves the atmosphere by dissolving in sea water up to the point where equilibrium is re-established. Thereafter the CO2 hangs about in the atmosphere for more or less ever. Very slowly it combines with the calcium in silicate rocks as mountains are weathered but we're talking a time-scale of a million years here.
That is not the only mechanism for removal of atmospheric CO2. The other is that plants take it up, and then some of that plant material ends up washed into the ocean, where it gets buried. This is the source of the oceanic methane hydrate that is going to burp.
Yeah, plants have a role; that's why the Keeling curve wobbles with the seasons, but it is not clear how vegetation will affect the grand scheme of things. It depends a bit on what we do to the vegetation. In the long term it's the lesser factor.
For those interested in getting a little closer to the truth of the complexity I'd suggest watching these two sections from a lecture on greenhouse gasses:
Circle 2, is one of the steps forwards: last week's Conference on European Climate Change Adaptation in Lisbon is now available to watch. (Good for those who like conferences but don't want to travel) Yo for the EU. http://adaptationfrontiers.eu/?id=presentations
Nice infographic (sorry but I can't think of a better word) to celebrate the 20th birthday (tomorrow) of the United Nations Framework on Climate Change (UNFCCC): http://unfccc.int/timeline/
