The 2k Network

Research on the last 1 to 2 ka has resulted in several multi-proxy reconstructions of global or hemispheric temperature (e.g., Rutherford et al., 2005; Mann et al., 2007; 2008). In addition, first attempts have been made to reconstruct other climatic parameters, at a high spatial and temporal resolution (e.g., Luterbacher et al., 2004).

Despite significant progress over the last few decades, we still do not sufficiently understand the precise sequence of changes related to regional climate forcings, internal variability, system feedbacks, and the responses of surface climate, land-cover, and bio- and hydro-sphere. Furthermore, at the decadal-to-centennial timescale we do not understand how sensitive the climate is to changes in solar activity, frequency of volcanic eruptions, greenhouse gas and aerosol concentration, and land cover.

It is understood that, at the continental- to regional-scale, climate is strongly modulated by internal variability, e.g., the NAO and Atlantic Multidecadal Oscillation (AMO) in the Atlantic area; and the El Niño Southern Oscillation (ENSO) and the Pacific Decadal Oscillations (PDO) in the Pacific area. However, the interactions of key processes at different temporal and spatial scales are not fully understood (Bengtsson et al., 2006).

Further, many parts of the globe lack adequate paleorecords for comparison with model simulations, and high-resolution (spatially and temporally) instrumental datasets are sparse. This is particularly true for the southern hemisphere and the tropics.

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Key questions

1. What did the main patterns and modes of climate variability on sub-decadal to orbital timescales look and operate like?

2. How do climate variability and extreme events relate to the important primary forcing factors, namely orbital, solar and volcanic?

3. What feedbacks operated to modulate the climate response?

 

2k Network Coordinators

Chris Turney
Darrell Kaufman
Hugues Goosse
Michael Evans
Lucien von Gunten (PAGES IPO)


For a more comprehensive list of 2k Network members, please visit the respective 2k Regional Working Group webpages.

 

2k Network meetings

Below is a list of trans-regional synthesis products by the 2k Network. Products of the various regional 2k groups can be found on the relevant group page.

Group: 2k

Journal articles

1.
Kaufman D, McKay N, Kiefer T & von Gunten L,
(2013),
A regional view of global climate change,
Global Change - IGBP,
Vol. 81,
18-23.

2.
PAGES 2k consortium,
(2013),
Continental-scale Temperature Variability During the Past Two Millennia,
Nature Geoscience,
Vol. 6,
339-346.

Videos

1.
PalMA UCM,
(2013),
Science and society facing climate change, do we understand each other?.

2.
Nature video,
(2013),
The Climate 2k Journal Club online hangout (9 May 2013).

 

All of the data used for the continental-scale temperature reconstructions are available for download through the NOAA Paleoclimatology website: http://www.ncdc.noaa.gov/data-access/paleoclimatology-data/products

Download the guidelines for 2k data collection here.

Regional working groups

The 2k Network is made up of 9 regional working groups. Each regional group collects and processes the best time series and spatial reconstructions of important state variables of the climate system (e.g., surface and 500 hPa geopotential, temperature and precipitation). The reconstructed maps and timeseries will be analyzed in combination with the best ensemble runs of existing ESMs.

 

2k_groups_v2

The 2k Network of regional Working Groups

 

> Africa2k (African climate of the last 2 millennia)
> Antarctica2k (Antarctic climate of the last 2 millennia)
> Arctic2k (Arctic climate of the last 2 millennia)
> Asia2k (Asian climate of the last 2 millennia)
> Aus2k (Australasian climate of the last 2 millennia)
> Euro-Med2k (European and Mediterranean climate of the last 2 millennia)
> LOTRED-SA (Long-Term Climate Reconstruction and Dynamics of South America)
> NAmerica2k (North American climate of the last 2 millennia)
> Ocean2k (Marine climate of the last 2 millennia)

Get involved

If you would like to be involved in one or more of the 2k Regional Working Groups, please contact the working group leaders for that region.

References

Bengtsson, L., Hodges, K. I. and Roeckner, E. 2006: Storm tracks and climate change, Journal of Climate, 19: 3518-3543.
Luterbacher, J., Dietrich, D., Xoplaki, E., Grosjean, M. and Wanner, H., 2004: European seasonal and annual temperature variability, trends, and extremes since 1500, Science, 303: 1499-1503.
Mann, M.E., Zhang, Z., Hughes, M.K., Bradley, R.S., Miller, S.K., Rutherford, S. and Ni, F., 2008: Proxy-based reconstructions of hemispheric and global surface temperature variations over the past two millennia, Proceedings of the National Academy of Sciences, 105: 13252–13257.
Mann, M.E., Rutherford, S., Wahl, E. and Ammann, C., 2007: Robustness of proxy-based climate field reconstruction methods, Journal Geophysical Research, 112: doi: 10.1029/2006JD008272.
Rutherford, S., Mann, M.E., Osborn, T.J., Bradley, R.S., Briffa, K.R., Hughes, M.K. and Jones, P.D., 2005: Proxy-based Northern Hemisphere surface temperature reconstructions: Sensitivity to methodology, predictor network, target season and target domain, Journal of Climate, 18: 2308-2329.