Despite a steady increase in atmospheric greenhouse gases (GHGs), global-mean surface temperature (T) has shown no discernible warming since about 2000, in sharp contrast to model simulations, which on average project strong warming 1-3 . The recent slowdown in observed surface warming has been attributed to decadal cooling in the tropical Pacific 1,4,5 , intensifying trade winds 5 , changes in El Niño activity 6,7 , increasing volcanic activity 8-10 and decreasing solar irradiance 7 . Earlier periods of arrested warming have been observed but received much less attention than the recent period, and their causes are poorly understood. Here we analyse observed and model-simulated global T fields to quantify the contributions of internal climate variability (ICV) to decadal changes in global-mean T since 1920. We show that the Interdecadal Pacific Oscillation (IPO) has been associated with large T anomalies over both ocean and land. Combined with another leading mode of ICV, the IPO explains most of the di erence between observed and model-simulated rates of decadal change in global-mean T since 1920, and particularly over the so-called 'hiatus' period since about 2000. We conclude that ICV, mainly through the IPO, was largely responsible for the recent slowdown, as well as for earlier slowdowns and accelerations in global-mean T since 1920, with preferred spatial patterns di erent from those associated with GHG-induced warming or aerosol-induced cooling. Recent history suggests that the IPO could reverse course and lead to accelerated global warming in the coming decades.The Pacific Decadal Oscillation (PDO; refs 11,12), or more generally the IPO (refs 13,14), switched from a warm phase to a cold phase around 1999 15 . This switch has been associated with a cooling trend since the early 1990s over the Equatorial Central and Eastern Pacific (ECEP; 15 • S-15 • N, 180 • -80 • W) that has contributed to the recent hiatus in global-mean T (refs 4,5). Modelling studies 1,16,17 have also shown that the IPO can modulate the rate of global warming through changes in ocean heat uptake. Given the welldocumented extra-tropical response to tropical forcings 18,19 , it is not surprising that IPO-associated sea surface temperature (SST) variations in the ECEP have had a large impact on global-mean T (ref. 1). The recent cooling of the ECEP has been accompanied by strengthening trade winds 5 and increasing ocean heat uptake 4,16,17,20 , typical of a La Niña event 21 but over decadal timescales. Although these studies all point to a major contribution of the ECEP to the recent global warming slowdown, it is unclear how much of the observed SST change in the ECEP is associated with ICV, particularly the IPO, and how much is due to external forcing change, such as stratospheric aerosols [7][8][9][10] . Previous analyses 22,23 a b Global-mean temperature anomaly difference (°C) r = 0.80, 0.94 OBS − model OBS EOF1 .2 0.1 0.0 −0.1 −0.2 −0.3 0.8 OBS (GISTEMP) Model (CMIP5) Model + 2 OBS EOFs Global-mean temperature anomaly (°C) 0.5 0..1...

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Previous studies have examined the projected climate types in China by 2100. This study identified the emergence time of climate shifts at a 1 • scale over China from 1990 to 2100 and investigated the temporal evolution of Köppen-Geiger climate classifications computed from CMIP5 multi-model outputs. Climate shifts were detected in transition regions (7%-8% of China's land area) by 2010, including rapid replacement of mixed forest (Dwb) by deciduous forest (Dwa) over Northeast China, strong shrinkage of alpine climate type (ET) on the Tibetan Plateau, weak northward expansion of subtropical winterdry climate (Cwa) over Southeast China, and contraction of oceanic climate (Cwb) in Southwest China. Under all future RCP (Representative Concentration Pathway) scenarios, the reduction of Dwb in Northeast China and ET on the Tibetan Plateau was projected to accelerate substantially during 2010-30, and half of the total area occupied by ET in 1990 was projected to be redistributed by 2040. Under the most severe scenario (RCP8.5), sub-polar continental winter dry climate over Northeast China would disappear by 2040-50, ET on the Tibetan Plateau would disappear by 2070, and the climate types in 35.9% and 50.8% of China's land area would change by 2050 and 2100, respectively. The results presented in this paper indicate imperative impacts of anthropogenic climate change on China's ecoregions in future decades.

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We introduce a new pragmatic procedure called the 'climate learning ladder' to structure policy analysis, support refl ection and identify critical decisions to support climate adaptation. This tool is the result of the refl exive learning process that occurred while developing innovative appraisal methods in the Alxa League of Inner Mongolia, China, and in the Guadiana river basin in the European Union. Building capacities to cope with climate change requires going beyond simply providing 'more knowledge' on climate impacts to policy makers. Instead, climate adaptation can be understood as a multi-step social process in which individuals and organizations need to learn how to (1) manage different framings of the issues at stake while raising awareness of climate risks and opportunities, (2) understand different motives for, and generate adequate incentives or sanctions to ensure, action, (3) develop feasible options and resources for individual and collective transformation and collaboration and (4) institutionalize new rights, responsibilities and feedback learning processes for climate adaptation in the long term.

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In this paper, we report on the results of an investigation into inter-decadal changes in moisture transport and divergence in East Asia for the two periods 1980–2001 and 1958–1979. The aim is to explore the mechanism of summer rainfall change in the region after abrupt changes. The relevant changes are calculated using ERA-40 daily reanalysis datasets. The results show that both stationary and transient eddy moisture transports to the Chinese mainland have declined since the abrupt change in atmospheric general circulation in the late 1970s, leading to more rainfall in South China and less in the North. The anomalous rainfall pattern coincides well with anomalous large-scale moisture divergence in the troposphere, of which stationary-wave or monsoon transport is dominant, in comparison with the contribution of the transient eddies. Furthermore, their divergences are found to be in opposite phases. In addition, meridional divergence is more important than its zonal counterpart, with an opposite phase in East Asia. Abnormal zonal moisture convergences appear in northwestern and northeastern parts of China, and are related to the excess rainfalls in these regions.An increase in transient eddy activity is one of the major mechanisms for excess rainfall in northern Xinjiang. Consequently, the anomalous rainfall pattern in East Asia results from a decline of the East Asian monsoon after the abrupt change, while the rainfall increase in northwestern China involves anomalies of both stationary waves and transient eddies on boreal westerly over the mid- and high latitudes.