Changes of shallow layer ground temperature can indicate the changes in active layer thickness. The soil thermal regime of the active layer was analyzed using the ground temperature data from 1977 to 2006 collected at 74 weather stations on the Qinghai-Tibet Plateau (QTP) and its adjacent areas. The results indicate that in the last 30 years the negative accumulated temperature at 5 cm depth below surface showed an increasing trend, but had different increment magnitudes in different regions. For the entire study area, the negative accumulated temperature increased 35℃ per decade. The freezing thickness of active layer showed a decreasing trend in the past 30 years in the regions. During the freezing period (cold season) the magnitude change of negative accumulated temperature was greater in the hinterland of QTP than in its peripheral areas, but it was more stably in a complete freeze-thaw cycle in the hinterland than in the peripheral areas. In the past 30 years, the values of freeze-thaw intensity (FTI) exhibited an increasing trend, which indicates that the stability of frozen ground has changed to some extent in the permafrost regions. In the QTP, latitude and altitude had a great impact on FTI. While altitude is below 4000 m, the decreasing rate of FTI with increase in altitude was different between the regions south and north of 33°N. The value in the south region was 2.5 times of that in the north region. While the altitude is above 4000 m, its impact on FTI values reduced relatively.

Detecting the growing season variability of terrestrial vegetation is crucial for identifying responses of ecosystems to recent climate change. Based on the normalized difference vegetation index (NDVI) and the air temperature and precipitation data, we have extracted the commencement of growing season (CGS) and the commencement of dekadly average temperature (CDAT) of 0 and 5℃ at typical weather stations on Tibetan Plateau from 1982-2009, and analyzed their spatiotemporal changes and the relationships between the CGS of vegetation and the air temperature and precipitation of winter and spring. The results show: the CDAT of 0 and 5℃ on the whole showed an advanced tendency, and the tendency of 5℃was more significant than that of 0℃; the multiple years average of CGS near typical weather stations gradually delayed from south to north and from east to west, and from 1982 to 2009, the CGS displayed an advanced tendency at all typical weather stations; and the CGS had a negative relation with the air temperature and precipitation of winter and spring, furthermore, the correlation of CGS with temperature was stronger than with precipitation. Different seasonal temperatures had different effects on CGS and the winter temperature affected CGS more than spring temperature.

Impact of climate warming on the growth and yields of spring wheat at high and low altitudes in the Qinghai Plateau was studied by using the observation data obtained at Minhe and Nuomuhong agricultural meteorological stations from 1980 to 2007. The results show that during the past 28 years the air temperature had an increase trend both at high and low altitudes, and the warming amplitude of annual air temperature was larger at high altitude than at low altitude. Responses of spring wheat at low altitude were an advanced sowing time, an unchanged mature stage, an extended growth period, and a declined yield, and at high altitude the responses were a postponed sowing time, an advanced mature stage, a shortened growth period, and an unstable yield with a larger fluctuation. The growth period of spring wheat was shortened by 11.7 d at high altitude and no significant change at low altitude when daily average temperature increased 1℃ in the growth period of spring wheat. Tillering stage was the turning point of growing period changes of spring wheat between the two places and also a “buffer” of the environment and crop population.

Methods of SVD and EOF were used to construct an integrated climate factor with dekad mean temperature, dekad total sunshine and precipitation from April to September; then an economy-climate model was built in combination with economic data to assess the grain yield condition of Jilin Province. The results show that the effect of integrated climate factor on grain yield was positive, and good evaluation was received in the simulation of grain yields and the assessment of annual harvest patterns using the economy-climate model.

Heilongjiang Province is one of major maize production bases for China. The maize yield fluctuation is closely linked with the country food security. Therefore, it is of significance to study the influence of climate warming on maize yields in this region under the background of climate warming. Based on the daily meteorological data of 22 weather stations and the maize yields of the main counties in 1961-2008 in Heilongjiang Province, the influence of climate warming on maize yield was carried out. The reference period was selected and the temperature influence coefficient was built. The results indicate: in the recent 50 years, the climate warming was favourable to the increasing tendency of maize yield. If 1961-1969 is used as the reference period, the contribution of climate warming to the maize yield in the 1970s, 1980s, 1990s and 2001-2008 is respectively 16.8%, 16.0%, 20.9% and 23.9%, relative to that of the 1960s. If 1970-1983 is used as the reference period, then the contribution of climate warming to the maize yield in the 1980s, 1990s and 2001-2008 is respectively 3.6%, 8.2% and 11.2% , relative to that of the1970s.

Using a long-term observation dataset of typical debris flows in Jiangjiagou ravine in Xiaojiang River basin, northern Yunnan Province, this paper analyzes the relationship between debris flows and rainfall as well as that between ENSO and JJA (June, July, August) precipitation of Zhanyi and Huize regular meteorological stations in the vicinity of Jiangjiagou ravine. The results show that the number of the debris-flow occurrences in Jiangjiagou Ravine are positively related to the JJA rainfall, which is significantly negatively related to the January SST in Nino3 region. Moreover, the annual number of debris flows strongly depends on the date of the first occurrence in that year, while the precipitation of May and June which triggers the first occurrence is negatively related to the Nino3 SST in winter and spring. The debris flow in Jiangjiagou is sensitive to the heavy rainfall (>25 mm) that responds well to the Nino3 SST. This suggests that the Nino3 SST in winter and spring has a powerful influence on the occurrences of debris flows in the Xiaojiang River basin. It is found that the number of debris flows in Jiangjiagou Ravine is negatively correlated with January SST in the Nino3 region: it is smaller in E1 Ni?o phase years and larger in La Ni?a phase years. Because the Nino3 SST signal is at least 4 months ahead of debris flows, so it might provide an indicator for forecasting debris flows in the northern Yunnan. Particularly, it is possible to use the winter information of ENSO to predict debris flows in the subsequent summer in Xiaojiang River basin and its vicinity.

Using the REOF (Rotated Empirical Orthogonal Function) method to analyze the climate factors (temperature and relative humidity) in the Haihe River basin, we divided the research area into different parts (sub-catchments). Haihe River basin can be divided into four temperature sub-catchments: northwest mountain sub-catchment, southern sub-catchment, west sub-catchment and central plains sub-catchment, and three moisture sub-catchments: central and western low value sub-catchment, southern high value sub-catchment, and northeast high value sub-catchment. The sub-catchment temperature and relative humidity distribution goes well with the water resources distribution.

Based on the observational precipitation and streamflow data in the Yanhe River basin during 1952-2008, the Mann-Kendall test was applied to investigate the trends of precipitation and streamflow. The effects of precipitation change and human activities on streamflow were quantified during the period of 1995-2008. The results indicate that the normal precipitation year accounted for 80.7 %, and most years were charactered by lower and low flow. Annual precipitation and streamflow both exhibited decreasing trends, and their abrupt changes occurred in 1995 and 2005, respectively. Compared with the baseline period of 1952-1994, the reduction of precipitation and streamflow in the period 1995-2008 was 11.1% and 27.3%, respectively; precipitation change contributed 46.2% to streamflow reduction, while human activities resulted in 53.8% of streamflow reduction.

This paper discusses the theories and methods of climate change risk study for carrying out basis for the research expansion in China. Climate change risks consist of three basic components including sensitivity, exposure and possibility. Uncertainty, future events, damaging and relativity are the major features of climate change risk. Climate change risk research includes two key steps including risk assessment and risk management, the former is the process, and the latter is the ultimate goal which is the basis for actions to address climate change. We also gave out the main framework and methods for climate change risk research. A case study of China誷 floods risk was taken to give an example of climate change risk study. Finally, we pointed out some main aspects of climate change risk research including ensemble-based probabilistic projection, quantitative risk assessment, risk zoning and mapping, risk management and so on.

Based on the updated 1990-2009 national greenhouse gas (GHG) inventories including Kyoto Protocol (KP) LULUCF-relevant data submitted by Annex I parties in 2011, GHG removals/emissions in LULUCF sector and LULUCF activities in the first two years (2008-2009) of the first commitment period of the KP were analyzed, and the cap for forest management activities in Decision 16/CMP.1 was retrospected. LULUCF sector of Annex I parties represents a net GHG removal on the whole, which increased by 65.9% from 1990 to 2009, with a significant inter-annual fluctuation. The net GHG removals of LULUCF sector in Annex I parties accounts for 7.41% of the total GHG emissions without LULUCF in 1990 and 13.68% in 2009. In 2008-2009, KP parties can claim a credit of 238 million ton CO2 equivalent per year from eligible KP LULUCF activities mainly from forest management (FM). The total net GHG removal of those KP parties accounts for 1.91% of the total GHG emissions in the base year without LULUCF. This means that about 45% of emission reduction committed by these parties can be offset by the net GHG removals of LULUCF activities. Analysis also indicates that the FM cap as contained in Decision 16/CMO.1 was overestimated by 59%, which allows some parties able to excessively use FM for their KP compliance, such as Russia, Italy and Japan. This may provide a caution to on-going negotiation of accounting rule for FM in the second commitment period.