The northernmost conifers in the world are located well above the Arctic Circle in the Taymir region of northern Siberia and have been recording the thermal environment for centuries to millennia. The trees respond to temperatures beyond the narrow season of actual cambial cell division by means of root growth, photosynthesis, lignification of cell walls, and other biochemical processes. Data from annual tree-ring widths are used to reconstruct May–September mean temperatures for the past four centuries. These warm-season temperatures correlate with annual temperatures and indicate unusual warming in the 20th century. However, there is a loss of thermal response in ring widths since about 1970. Previously the warmer temperatures induced wider rings. Most major warming and cooling trends are in agreement with other high-latitude temperature reconstructions based on tree-ring analyses with some regional differences in timing of cooling in the late 18th century and of warming in the late 19th century.

На основе 7000-летних древесно-кольцевых хронологий по сосне остистой (Pinus aristata) с верхней границы леса Белых гор и Большого Бассейна Северной Америки (шкала Фергюсона), и ли- ственницы сибирской (Larix sibirica) с полярной границы леса на полуострове Ямал (Северная Евразия, шкала Хантемирова) реконструирован отрезок голоцена от его климатического оптимума до современ- ности. Выявлен математически точный ритм климата, трижды повторяющийся на графиках дендрохро- нологических шкал с частотой в 2600 лет. Определена связь стволового прироста с колебаниями уровня Мирового океана, Каспия и ледовитостью Арктики, а также развитием глобальных засух. Закономерности изменений климата, синхронно записанные в сверхдлинных дендрошкалах двух ма- териков Северного полушария астрономически точным ритмом в 2600 лет, наиболее достоверно отража- ют климат Земли в последних тысячелетиях и дают единственный ключ к его прогнозу на будущее Based on 7,000-year tree-ring chronologies for the Pinus aristata from the tree line of White Mountains and Great Basin of North America (Ferguson’s scale), and Larix sibirica from the polar forest edge on Yamal Peninsula (Northern Eurasia, Khantemirov’s scale) reconstructed the Holocene section from its climatic optimum to the present day. Mathematically precise global rhythm, which repeat three times on charts of dendrochronological scales with a frequency in 2,600 years, are revealed. The relationship of the stem growth with fluctuations in level of the World Ocean, Caspian Sea and Arctic sea ice, as well as the development of global droughts, has been determined. Regularities of the climate change, synchronously recorded in ultra-long dendroscales of two continents of the Northern Hemisphere by astronomically accurate rhythm in 2,600 years, most reliably reflect the Earth’s climate in recent millennia and provide the only key to its prediction in future.