Limits...
Was millennial scale climate change during the Last Glacial triggered by explosive volcanism?

Baldini JU, Brown RJ, McElwaine JN - Sci Rep (2015)

Bottom Line: Additionally, previous research reported a strong statistical correlation between the timing of Southern Hemisphere volcanism and Dansgaard-Oeschger (DO) events (>99% confidence), but did not identify a causative mechanism.Volcanic aerosol-induced asymmetrical hemispheric cooling over the last few hundred years restructured atmospheric circulation in a similar fashion as that associated with Last Glacial millennial-scale shifts (albeit on a smaller scale).This resulted in Greenland cooling, Antarctic warming, and a southward shifted ITCZ.

View Article: PubMed Central - PubMed

Affiliation: Department of Earth Sciences, University of Durham, Durham, DH1 3LE, UK.

ABSTRACT
The mechanisms responsible for millennial scale climate change within glacial time intervals are equivocal. Here we show that all eight known radiometrically-dated Tambora-sized or larger NH eruptions over the interval 30 to 80 ka BP are associated with abrupt Greenland cooling (>95% confidence). Additionally, previous research reported a strong statistical correlation between the timing of Southern Hemisphere volcanism and Dansgaard-Oeschger (DO) events (>99% confidence), but did not identify a causative mechanism. Volcanic aerosol-induced asymmetrical hemispheric cooling over the last few hundred years restructured atmospheric circulation in a similar fashion as that associated with Last Glacial millennial-scale shifts (albeit on a smaller scale). We hypothesise that following both recent and Last Glacial NH eruptions, volcanogenic sulphate injections into the stratosphere cooled the NH preferentially, inducing a hemispheric temperature asymmetry that shifted atmospheric circulation cells southward. This resulted in Greenland cooling, Antarctic warming, and a southward shifted ITCZ. However, during the Last Glacial, the initial eruption-induced climate response was prolonged by NH glacier and sea ice expansion, increased NH albedo, AMOC weakening, more NH cooling, and a consequent positive feedback. Conversely, preferential SH cooling following large SH eruptions shifted atmospheric circulation to the north, resulting in the characteristic features of DO events.

No MeSH data available.


Related in: MedlinePlus

Global volcanic eruption history over the last 80 ka, based ondata in the LaMEVE database, and ice volume conditions.(a) Number of Magnitude ≥6 (Pinatubo-sized or larger) NHand SH eruptions per two millennia from present to 80 ka BP. Thelow number of known SH volcanic eruptions prior to the last two ka reflectsa significant undercount in known eruptions. (b) Latitude and ages ofknown Magnitude ≥6 volcanic eruptions from present to80 ka BP36. (c) A histogram of abruptGreenland warming events37, the Red Sea sea levelreconstruction (interpreted as reflecting global ice volume)38 (solid black line), and 65°N insolation35(dashed blue line). Intervals characterised by high ice volume and lowinsolation hypothesised as relatively insensitive to SH eruptions arehighlighted in blue; intervals with very low ice volume lacking the positivefeedback required to sufficiently amplify volcanic eruptions are highlightedin orange.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4663491&req=5

f5: Global volcanic eruption history over the last 80 ka, based ondata in the LaMEVE database, and ice volume conditions.(a) Number of Magnitude ≥6 (Pinatubo-sized or larger) NHand SH eruptions per two millennia from present to 80 ka BP. Thelow number of known SH volcanic eruptions prior to the last two ka reflectsa significant undercount in known eruptions. (b) Latitude and ages ofknown Magnitude ≥6 volcanic eruptions from present to80 ka BP36. (c) A histogram of abruptGreenland warming events37, the Red Sea sea levelreconstruction (interpreted as reflecting global ice volume)38 (solid black line), and 65°N insolation35(dashed blue line). Intervals characterised by high ice volume and lowinsolation hypothesised as relatively insensitive to SH eruptions arehighlighted in blue; intervals with very low ice volume lacking the positivefeedback required to sufficiently amplify volcanic eruptions are highlightedin orange.

Mentions: We focus on the interval from 30 to 80 ka BP because of the high density ofmillennial-scale climate oscillations within that interval, and because the proposedmechanism would be most effective during intervals of time characterised by intermediateice volume and 65°N insolation, such as most of this interval (see Supplementary Information) (Fig. 5). Unfortunately, the volcanological catalogue of known eruptionsprior to 10 ka BP is very incomplete because: (i) erosion removesvolcanic deposits from the geologic record and increases uncertainty associated with theestimation of eruption magnitude, (ii) burial by younger deposits hides olderdeposits from study, and (iii) many volcanoes still remain understudied or evenunknown. Even over only the last one thousand years, instances exist where evidence oflarge eruptions is apparent in ice core volcanogenic sulphate records but the volcanoresponsible has only recently been identified (e.g., Rinjani, 1257 A.D.) or is stillunknown (e.g., the 1809 A.D. eruption). Prior to the Holocene, large eruptions from SHcalderas are particularly underrepresented (see Supplementary Information).


Was millennial scale climate change during the Last Glacial triggered by explosive volcanism?

Baldini JU, Brown RJ, McElwaine JN - Sci Rep (2015)

Global volcanic eruption history over the last 80 ka, based ondata in the LaMEVE database, and ice volume conditions.(a) Number of Magnitude ≥6 (Pinatubo-sized or larger) NHand SH eruptions per two millennia from present to 80 ka BP. Thelow number of known SH volcanic eruptions prior to the last two ka reflectsa significant undercount in known eruptions. (b) Latitude and ages ofknown Magnitude ≥6 volcanic eruptions from present to80 ka BP36. (c) A histogram of abruptGreenland warming events37, the Red Sea sea levelreconstruction (interpreted as reflecting global ice volume)38 (solid black line), and 65°N insolation35(dashed blue line). Intervals characterised by high ice volume and lowinsolation hypothesised as relatively insensitive to SH eruptions arehighlighted in blue; intervals with very low ice volume lacking the positivefeedback required to sufficiently amplify volcanic eruptions are highlightedin orange.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4663491&req=5

f5: Global volcanic eruption history over the last 80 ka, based ondata in the LaMEVE database, and ice volume conditions.(a) Number of Magnitude ≥6 (Pinatubo-sized or larger) NHand SH eruptions per two millennia from present to 80 ka BP. Thelow number of known SH volcanic eruptions prior to the last two ka reflectsa significant undercount in known eruptions. (b) Latitude and ages ofknown Magnitude ≥6 volcanic eruptions from present to80 ka BP36. (c) A histogram of abruptGreenland warming events37, the Red Sea sea levelreconstruction (interpreted as reflecting global ice volume)38 (solid black line), and 65°N insolation35(dashed blue line). Intervals characterised by high ice volume and lowinsolation hypothesised as relatively insensitive to SH eruptions arehighlighted in blue; intervals with very low ice volume lacking the positivefeedback required to sufficiently amplify volcanic eruptions are highlightedin orange.
Mentions: We focus on the interval from 30 to 80 ka BP because of the high density ofmillennial-scale climate oscillations within that interval, and because the proposedmechanism would be most effective during intervals of time characterised by intermediateice volume and 65°N insolation, such as most of this interval (see Supplementary Information) (Fig. 5). Unfortunately, the volcanological catalogue of known eruptionsprior to 10 ka BP is very incomplete because: (i) erosion removesvolcanic deposits from the geologic record and increases uncertainty associated with theestimation of eruption magnitude, (ii) burial by younger deposits hides olderdeposits from study, and (iii) many volcanoes still remain understudied or evenunknown. Even over only the last one thousand years, instances exist where evidence oflarge eruptions is apparent in ice core volcanogenic sulphate records but the volcanoresponsible has only recently been identified (e.g., Rinjani, 1257 A.D.) or is stillunknown (e.g., the 1809 A.D. eruption). Prior to the Holocene, large eruptions from SHcalderas are particularly underrepresented (see Supplementary Information).

Bottom Line: Additionally, previous research reported a strong statistical correlation between the timing of Southern Hemisphere volcanism and Dansgaard-Oeschger (DO) events (>99% confidence), but did not identify a causative mechanism.Volcanic aerosol-induced asymmetrical hemispheric cooling over the last few hundred years restructured atmospheric circulation in a similar fashion as that associated with Last Glacial millennial-scale shifts (albeit on a smaller scale).This resulted in Greenland cooling, Antarctic warming, and a southward shifted ITCZ.

View Article: PubMed Central - PubMed

Affiliation: Department of Earth Sciences, University of Durham, Durham, DH1 3LE, UK.

ABSTRACT
The mechanisms responsible for millennial scale climate change within glacial time intervals are equivocal. Here we show that all eight known radiometrically-dated Tambora-sized or larger NH eruptions over the interval 30 to 80 ka BP are associated with abrupt Greenland cooling (>95% confidence). Additionally, previous research reported a strong statistical correlation between the timing of Southern Hemisphere volcanism and Dansgaard-Oeschger (DO) events (>99% confidence), but did not identify a causative mechanism. Volcanic aerosol-induced asymmetrical hemispheric cooling over the last few hundred years restructured atmospheric circulation in a similar fashion as that associated with Last Glacial millennial-scale shifts (albeit on a smaller scale). We hypothesise that following both recent and Last Glacial NH eruptions, volcanogenic sulphate injections into the stratosphere cooled the NH preferentially, inducing a hemispheric temperature asymmetry that shifted atmospheric circulation cells southward. This resulted in Greenland cooling, Antarctic warming, and a southward shifted ITCZ. However, during the Last Glacial, the initial eruption-induced climate response was prolonged by NH glacier and sea ice expansion, increased NH albedo, AMOC weakening, more NH cooling, and a consequent positive feedback. Conversely, preferential SH cooling following large SH eruptions shifted atmospheric circulation to the north, resulting in the characteristic features of DO events.

No MeSH data available.


Related in: MedlinePlus