On Tue, Feb 11, 2014 at 4:22 PM, LizR <[email protected]> wrote: > On 12 February 2014 00:38, Richard Ruquist <[email protected]> wrote: > >> On Tue, Feb 11, 2014 at 3:41 AM, LizR <[email protected]> wrote: >> >>> On 11 February 2014 19:01, Richard Ruquist <[email protected]> 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 [email protected]. > To post to this group, send email to [email protected]. > 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 [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/groups/opt_out.
