On Tue, Feb 11, 2014 at 4:22 PM, LizR <lizj...@gmail.com> wrote: > On 12 February 2014 00:38, Richard Ruquist <yann...@gmail.com> wrote: > >> On Tue, Feb 11, 2014 at 3:41 AM, LizR <lizj...@gmail.com> wrote: >> >>> On 11 February 2014 19:01, Richard Ruquist <yann...@gmail.com> wrote: >>> >>>> The Vostok ice core data, from which Atm. temperature and CO2 content >>>> have been extracted, suggests that at least for the last half million years >>>> climate change has been a natural occurrence, apparently based on >>>> fluctuations on earth-incident solar radiance. That is except for the last >>>> 10,000 years, when the climate has been relatively stable. My fear is that >>>> this relative stability will come to an end and we may return to the >>>> temperature fluctuations that typified the ice ages. >>>> >>> >>> Yes, imho it was most likely the interglacial that allowed agriculture >>> to flourish, and with it civilisation. >>> >>> As far as returning to fluctuating temperatures goes, increasing >>> atmospheric CO2 by a staggering 50% since 1800 won't have helped in that >>> department... >>> >> >> That we are currently in an interglacial period >> suggests that another glacial period is coming(;<) >> > > It certainly would normally. I don't know if it does now we've bumped up > atmospheric CO2 50% in 2 centuries (and we *have *had the hottest years > on record with monotonous regularity over the last couple of decades, so, > so far the effect is a warming trend - though that could have unexpected / > counter-intuitive consequences of course - I mean above those it's already > having!) > >> >> In previous plunges into glacial periods, the CO2 atm content >> continued to increase for up to 1000 years after the temperature peaked. >> So IMO an increasing CO2 may actually be responsible for the plunge. >> > >> The mechanism is that the increased atm energy abs produced by increased >> CO2 >> results in fluctuations in the jet stream down to most of the landmass >> in North America, and northern Europe and Asia, significantly increasing >> reflection from snow (rather than absorption) of solar radiation over land >> thereby cooling the earth significantly. >> > > Hmm, that seems possible I suppose. Most of the thermal energy is stored > in the oceans, however, so we would expect them to expand (and possibly > release dissolved CO2, methane, etc) so this is rather hypothetical (and in > conflict with the opinions of 99.7% of climate scientists, if I remember > correctly). > >> >> Oceanic absorption would be relatively constant >> so climate change would be a Northern Hemisphere effect. >> > > I don't see that. Warming oceans have less capacity to absorb gas from the > atmosphere, and would eventually start to release it back again, at which > point we'll really be into runaway feedback (or our grandchildren will). > It's possible that's what happened in the relatively fast warming around > the Paleocene-Eocene Thermal Maximum. See for example > http://en.wikipedia.org/wiki/Palaeocene-Eocene_Thermal_Maximum#Methane_release >
The climate in the so-called Palaeocene-Eocene_Thermal_Maximum<http://en.wikipedia.org/wiki/Palaeocene-Eocene_Thermal_Maximum#Methane_release> lasted for 20 million years. Compared to the recent ice ages for only 1/2 million years, it was a very stable climate. That may be where we are headed. But I fear that we will return to more glaciation. http://www.google.com/imgres?imgurl=http://www.meltonengineering.com/Zachos%25202001%2520PETM%252072%2520dpi.jpg&imgrefurl=http://blog.concord.org/what-caused-the-paleocene-eocene-thermal-maximum&h=285&w=177&sz=1&tbnid=6QMv8FTf8uJhzM:&tbnh=186&tbnw=115&zoom=1&usg=__wTlZHQ6Tyy42yi8HlCVB2eoB-ck=&docid=LavOcNHQ3o3thM&itg=1&sa=X&ei=mJf6Ur6sKMuQ0QH_q4HgBw&ved=0CKUBEPwdMAo > > -- > You received this message because you are subscribed to the Google Groups > "Everything List" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to everything-list+unsubscr...@googlegroups.com. > To post to this group, send email to everything-list@googlegroups.com. > Visit this group at http://groups.google.com/group/everything-list. > For more options, visit https://groups.google.com/groups/opt_out. > -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/groups/opt_out.
