James Shulmeister Assoc. Prof. James Shulmeister Department of Geological Sciences University of Canterbury New Zealand If you would like to interview this scientist, please contact Leah Christen. > biographical information > abstract > paper

Biographical Information:

I research terrestrial paleoclimates focusing on the Pacific Basin, especially New Zealand, Australia and Antarctica. I undertake geologically- and eologically-based investigations of glacial and coastal systems and I study lake records. I am PAGES national representative for New Zealand, a member of the PAGES-PEPII scientific steering committee, a member of the INQUA paleoclimate commission and the co-leader of an INQUA paleoclimate project. A physical geographer by training, I graduated from Trinity College Dublin in 1984. I gained my MSc from Queen’s University in Canada and my PhD at the Australian National University in 1991. I was a Post-Doctoral Fellow at the University of Canterbury in New Zealand, a visiting Assistant Professor at the University of Southern California, and a lecturer at Victoria University of Wellington, before returning to the University of Canterbury, where I am currently an Associate Professor in Quaternary Geology

Abstract:

The PANASH program has significantly advanced our understanding of past climate change on a global basis and helped to integrate paleoscience across regions and between disciplinary specialists. PANASH science allows us to constrain predictions for future climate change and to contribute to the management and mitigation of such changes. We identify three broad areas where PANASH science makes key contributions:

1. Insights into global climate drivers through the recognition of patterns and timing of global changes. The global synchronicity or otherwise of glacial advances during the last glaciation is critical to understanding inter-hemispheric links in climate. Work in PEP I demonstrated that the tropical Andes in South America was deglaciated earlier than the Northern Hemisphere (NH) and that an extended warming occurred from c. 21,000 cal years BP. The general pattern is consistent with Antarctica and has now been replicated from studies in Southern Hemisphere (SH) regions of the PEP II transect. That significant deglaciation of SH alpine systems and Antarctica led deglaciation of NH ice sheets may reflect either i) faster response times in the former, ii) regional moisture patterns that influenced glacier mass balance, or iii) a SH temperature forcing that led changes in the NH.

2. The recognition and definition of longer-term changes in modes of operation of climate phenomena. Work across all the PEP transects has led to the recognition that the El Niño Southern Oscillations (ENSO) phenomenon has changed markedly through time. It now appears certain that ENSO either did not operate, or operated in a greatly reduced mode during the last glacial termination and during the early Holocene. In the modern ENSO phenomenon both inter-annual and seven-year periodicities are present, with the inter-annual signal dominant. Paleo-data demonstrate that the relative importance of the two periodicities changes through time, with seven-year periodicities dominant in the early Holocene.

3. The recognition of climate modulation of oscillatory systems by abrupt climate events. We will describe interactions between ENSO and the tropical oceans during the early Holocene. We also examine the role of ENSO and other oscillatory climate systems in controlling the manifestation of an abrupt SH climate event, the Antarctic cold reversal (ACR), in the New Zealand region.

PANASH (paleoclimates of the Northern and Southern Hemisphere)

PEP (Pole-Equator-Pole transects in the PANASH program; PEP I – Americas; PEP II – East Asia-Australasia; PEP III – Europe-Africa)

Paper:

This talk highlights some of the contributions of the Paleoclimates of the Northern and Southern Hemisphere (PANASH) project to understanding and ultimately managing climate change. The project is very large incorporating hundreds of scientists from around the world so instead of trying to cover all results we are focusing on a few important findings, largely from the southern hemisphere, as an example of this work.

We identify three main areas where PANASH science helps contribute to understanding global change:

1.   Insights into global climate engines through the recognition of patterns and timing of global changes. Changes in global climate systems of a similar magnitude to the forecast changes under global warming predictions last happened during the ice ages. In particular, the global climate warmed up very rapidly at the end of the last ice age. By examining how and where the warming occurred during the end of the last ice age we can evaluate how future warming might impact us. Our work shows that the tropical Andes in South America was ice free earlier than the northern hemisphere (NH) and that an extended warming occurred from c. 21,000 years ago. The general pattern is consistent with Antarctica and has now been replicated from studies in southern hemisphere (SH) regions. That significant deglaciation of SH mountain areas and Antarctica led the retreat of NH ice sheets may reflect either i) faster response times in the south, ii) regional snowfall patterns are actually more significant, or iii) a that a southern hemisphere warming led changes in the north.

2.   The recognition and definition of longer-term changes in modes of operation of climate systems. Our work shows that El Niño behaved differently during the recent geological past. This means that under future climate change scenarios the El Niño may change the way it operates, with significant impacts for world climate. It now appears certain that El Niño either did not operate, or operated in a greatly reduced form at the end of the last ice age and during the early part of the modern warm phase. Our data demonstrate that the relative importance of a seven-year El Niño cycle rather than the 1-2 year cycle that now dominates.

3.   The recognition of abrupt climate change events and how they impact the climate system. We will describe interactions between El Niño and the tropical oceans during the early part of the modern warm phase. We also examine the role and response of El Niño and other climate systems during abrupt climate change events. The example we will use is a SH event known as the Antarctic Cold Reversal and we will show how this event interacts with modern climate systems.

In all of the above cases, you could never determine these changes by looking at the modern climate or by climate modeling. Historical and geological investigations of climate change are critical to save us from future climate shocks and work under the PANASH program is a major contributor to this science.



Figure 1. ENSO
Comparison between proxy climate records from Equador, New Zealand and South Africa for the last 10,000 years (The Holocene). These records show that El Niños were weaker during the first half of the Holocene than during the last 5,000 years. They also show very good coherence between tropical South America and Australasia (in this case New Zealand), but a much weaker relationship with South Africa. The inset picture from Pepper et al., 2004 (bottom right) shows the apparent absence of El Niño from New Zealand in the very early Holocene, again in good agreement with South American data.



Figure 2. Deglaciation
This figure shows a variety of climate proxy signals (ice cores, pollen records, rock flour from glaciers) from sites extending from the Antarctic (top) to the Arctic (bottom) but concentrating in the SH. They cover the period from 21,000 to 10,000 years ago which is the end of the last ice age, a period of rapid warming often used as an analogue for modern human induced global warming. It shows that at the end of the ice ages deglaciation (ice retreat and warming) seems to occur early in the tropics and then spread into the SH, before finally moving to the NH. Three early climate shifts are highlighted in pink, while the more well-known climate events in the late deglaciation, the Younger Dryas and Antarctic Cold Reversal, are shown in gray.