Reconstructions 2003–2006 Hockey stick graph

ten of hemispheric temperature reconstructions published december 2005, 4 omitted because had been superseded later reconstructions or due data plotting issues.

using various high-resolution proxies including tree rings, ice cores , sediments, mann , jones published reconstructions in august 2003 indicated late 20th century warmth unprecedented @ least past 2 millennia northern hemisphere. conclusions southern hemisphere , global mean temperature limited sparseness of available proxy data in southern hemisphere @ present. concluded extent ‘medieval’ interval of moderately warmer conditions can defined ad 800 – 1400, hemispheric warmth during interval dwarfed in magnitude late 20th century warmth.

borehole climate reconstructions in paper pollack , smerdon, published in june 2004, supported estimates of surface warming of around 1 °c (1.8 °f) on period 1500 2000.

in study published in november 2004 edward r. cook, jan esper , rosanne d arrigo re-examined 2002 paper, , supported mbh. concluded annual temperatures ad 2000 on extra-tropical nh land areas have exceeded 0.3 °c warmest previous interval on past 1162 years .

a study anders moberg et al. published on 10 february 2005 used wavelet transform technique reconstruct northern hemisphere temperatures on last 2,000 years, combining low-resolution proxy data such lake , ocean sediments century-scale or longer changes, tree ring proxies used annual decadal resolution. found there had been peak of temperatures around ad 1000 1100 similar reached in years before 1990, , supported basic conclusion of mbh99 stating find no evidence earlier periods in last 2 millennia warmer conditions post-1990 period .

at end of april 2005 science published reconstruction j. oerlemans based on glacier length records different parts of world, , found consistent independent evidence period 1600 1990 supporting other reconstructions regarding magnitude , timing of global warming.

on 28 february 2006 wahl & ammann 2006 accepted publication, , in press copy made available on internet. 2 more reconstructions published, using different methodologies , supporting main conclusions of mbh. rosanne d arrigo, rob wilson , gordon jacoby suggested medieval temperatures had been 0.7 °c cooler late 20th century less homogenous, osborn , briffa found spatial extent of recent warmth more significant during medieval warm period. followed in april third reconstruction led gabriele c. hegerl.