On 31 March 2014, Climate Change 2014: Impacts, Adaptation, and Vulnerability, the Working Group II contribution to the IPCC Fifth Assessment Report (WGII AR5) was released. This report concluded that climate change had caused an extensive and far-reaching influence on global natural and human systems, including 11 sectors and 9 regions (i.e. all continents, polar regions and small islands). Eight kinds of key risks that span sectors and regions are investigated to threaten the natural and human systems. The human systems have obvious vulnerability and exposure to climate risks, in particularly to the climatic extremes. The climatic resilience of natural system and human society should be enhanced through disaster risk management with core of iterative processes and synergies. Combined with mitigation, and transformations in economy, society, technology, and political decisions and actions, a sustainable social and economic development can enable climate-resilient pathways by effective adaptation.

Through analysis of the evolvement of major conclusions and methods for impacts and adaptation on climate change in the IPCC WGII five assessment reports, the causes and their impacts on international adaptation negotiations and domestic adaptation policies were studied. It points out that because of the rapid increase of literature, sophistication of methods and tools for evaluation and adaptation, increasing concerns and more emphasis on adaptation, IPCC further confirms that climate change has had and will have extensive and profound impacts on natural and human systems; future social-economic pathways, adaptation and mitigation, and risk governance at different levels will affect climate-related risks. IPCC assessment reports promote the formation and implementation of adaptation policies both at the international and national levels. Although China has merged adaptation into related domestic policies, still there are problems in cognition, capacity, mechanisms and institutions. More efforts are needed to enhance national and local adaption efforts.

The Working Group II (WGII) contribution to the IPCC AR5, Climate Change 2014: Impact, Adaptation, and Vulnerability, comprehensively assessed the needs, options, opportunities, constraints, and limits of adaptation with a new focus on the climate-related risks in a systematic manner. As a main information source for the negotiations on the 2015 Agreement under the UNFCCC, the key findings of the WGII reports will have significant influences on many important issues including global long term goal, adaptation, loss and damage, etc. The reports contain the most up-to-date and comprehensive scientific knowledge on climate change, thus to achieve a better understanding of the conclusions, which could further facilitate the domestic work and international negotiation.

Working Group II contribution to IPCC Fifth Assessment Report was issued recently, it concluded that many biota and ecosystems have been affected significantly due to climate change, and these changes will be continued in the future. Climate change and human activities are projected to be powerful stressors on terrestrial and freshwater ecosystems in the 21st century, the extinction risk of many species will increase, and some ecosystems will change irreversibly. The inherent capacity of ecosystems will be insufficient to cope with projected climate change in the future, adaptation strategies and actions can increase the adaptive capacity of species and ecosystems to climate change. Coastal systems and low-lying areas are affected strongly by climate change and human activities, the consequences of impact vary from place to place. The global mean sea level rise is projected to be 0.28 -0.98 m by 2100, relative sea level rise is different with regional variations. Hundreds of millions of people will be affected by coastal flooding by 2100. The relative costs of adaptation vary strongly between and within regions and countries for the 21st century. The benefits of protecting against increased coastal flooding and land loss are larger than the social and economic costs of inaction at the global scale. The adaptive capacity of coastal areas has progressed much more significantly in developed countries than in developing countries, and so does the climate resilience of sustainable development.

The key conclusions on the effects of climate change and the adaptability evaluation from the chapter 30 (The Ocean) in the Fifth Assessment Report by Working Group II of the Intergovernmental Panel on Climate Change (IPCC WGII AR5) were briefly presented in this article. The world’s non-polar ocean as a whole region was considered for the first time in this report, and it was separated into seven major sub-regions based on marine ecosystem structure and functioning as well as key oceanographic features. Assessment results indicated that, the global average sea surface temperatures have increased since the beginning of the 20th century, and uptake of CO₂ has decreased ocean pH in all ocean sub-regions, particularly at high latitudes, fundamentally changing the ocean physical and chemical properties, marine ecological systems in the past 60 years and posing a number of key risks to ocean and coastal issues from climate change, such as, distributional shift in marine species, changes to fisheries capture potential with region variations, reduced biodiversity and fisheries abundance and coastal protection by coral reef, etc. Meanwhile, the related adaptive issues and prospects were put forward. In addition, the deficiencies and difficulties in the assessment report were also discussed, as well as outlined, the related research work needed to be further explored in China.

Working Group II contribution to the IPCC Fifth Assessment Report (AR5) presents new findings of cross-regional impacts of climate change. In Africa, climate change will amplify existing stress on water availability and on agricultural systems particularly in semi-arid environments. In Europe, climate change will increase the likelihood of systemic failures across European countries caused by extreme climate events affecting multiple sectors. In Asia, climate change will cause declines in agricultural productivity in many subregions of Asia, for crops such as rice. In Australasia, without adaptation, further changes in climate, atmospheric CO₂ and ocean acidity are projected to have substantial impacts on water resources, coastal ecosystems, infrastructure, health, agriculture and biodiversity. In North America, many climate-related hazards which carry risk, particularly related to severe heat, heavy precipitation, and declining snowpack, will increase in frequency and/or severity in the next decades. In Central and South America, despite improvements, high and persistent levels of poverty in most countries result in high vulnerability to climate variability and change. In the Arctic, climate change and often-interconnected non-climate-related drivers, including environmental changes, demography, culture, and economic development, interact to determine physical, biological and socioeconomic risks, with rates of change that may be faster than social systems can adapt. Small islands have high vulnerability to climatic and non-climatic stressors. Warming will increase risks to ocean ecosystems.

IPCC launched Climate Change 2014: Impacts, Adaptation, and Vulnerability and pointed out that since AR4 the framing of adaptation has moved further from a focus on biophysical vulnerability to the wider social and economic drivers of vulnerability and people’s ability to respond. It expounded the relationships between climate risk and social development, pointed out how adaptation play an important role in climate-related risk management and that strategies and approaches to climate change adaptation include efforts to decrease vulnerability or exposure and/or increase resilience or adaptive capacity. It presented the concept of adaptation limits and expounded its meaning to climate change adaptation. It put forward climate resilient pathways for sustainable development, significant co-benefits and synergies exist between mitigation and adaptation and between alternative adaptation responses, transformation is a necessary option to cope with climate change. The report considered climate change, impacts, adaptation and social-economics processes are not simple linear relationship and need to be recognized and understood in a compound system.

New and longer-term observations, and more extensive analyses on existing data reveal that impacts of recent changes in climate on natural systems, human and managed systems occur on all continents and across the oceans. This paper summarizes the recent findings from Working Group II contribution to the IPCC Fifth Assessment Report on the detection and attribution of observed changes, including assessment of the different types of impacted systems and progress of detection and attribution methods. And research and knowledge gap requiring more concerns are also presented in this paper.

Based on the daily mean temperature and sunshine duration data of 824 stations in China from 1959 to 2005 and the NCEP/NCAR daily total cloud cover data, China is devided into four and six sub-regions for winter and summer mean temperature respectively with REOF method. The four sub-regions for winter are the east of Tibetan Plateau, Northeast China and eastern Inner Mongolia, most of Tibetan Plateau, and Xinjiang Province. The six sub-regions for summer are east of the Northwest and North China, the reaches of the Yangtze and Yellow Rivers, southern Southwest China and South China, Northeast China and eastern Inner Mongolia, the central and north of Xinjiang, west of southern Xinjiang. Average temperature of all regions except summer region II (the reaches of the Yangtze and Yellow Rivers) has an upward tendency in both winter and summer, besides, the tendency in winter is more significant. Except winter region II (Northeast China and eastern Inner Mongolia), there is a positive correlation between temperature and sunshine in all regions without consideration of the impact of total cloud, and the positive correlation of summer is more significant than that of winter. Taking no account of sunshine, the negative correlation between temperature and total cloud is significant in summer region I (east of the Northwest and most of North China) , as well as in summer region VI (west of southern Xinjiang) and winter region II (Northeast China and eastern Inner Mongolia).

The capabilities of the latest global climate models in simulating the precipitation in China from 1980 to 2005 have been assessed from the results of multiple precipitation observations and outputs from 43 models that participate in the fifth phase of the Coupled Model Intercomparison Project (CMIP5). As shown from the results, most of the CMIP5 models can reproduce the basic spatial pattern that the precipitation increases from the northwest to the southeast in China. Most CMIP5 models simulate less precipitation in South China and more in the western part of the Tibet Plateau than the observations, which is similar to the results in models that participate in the third phase of the Coupled Model Intercomparison Project (CMIP3). The seasonal variation of wet summer and dry winter can be well captured, but the magnitude of precipitation is overestimated by the models. From the results of EOF analyses, most CMIP5 models have the ability to simulate the spatial-temporal characteristics of the annual mean precipitation in China, and the CMIP5 multi-model mean shows better performance than CMIP3. The multi-model ensemble mean shows better performance on various time scales than a single model. The capabilities of the 6 Chinese models are comparable to those of the foreign models, and FGOALS-g2 and BCC-CSM1-1-m have relatively better performances among them.

Using MODIS dataset during 2001-2012, impacts of water body at daytime and nighttime on land surface temperatures due to the Three Gorges Project were analyzed both in winter and summer. To fully consider the impacts of topography, it is found that high land surface temperature mainly located in the eastern part of Sichuan basin at daytime, and in the Yangtze River at nighttime. Diurnal temperature ranges in the Yangtze River and high altitude area are small, also diurnal temperature ranges in the water body in summer are less than those in winter. After removing impacts of climate background by subtracting the average land surface temperatures over the buffer zone XI from the water body and buffer zones I-X, temporal trends in winter daytime climb up in water body and buffer zones I-VI, land surface temperatures at winter night in the same range also have significant rise. Removing the impacts of climate background and then separating the topographical effects through subtracting the variables after impounding (2003-2012) from ones before impounding (2001-2002), it is shown that, relative to the period before impounding, winter land surface temperatures after impounding obviously increase, and the intensity and range at nighttime are stronger than at daytime. Summer land surface temperatures decrease, the intensity at nighttime is weaker than at daytime, respectively, and the corresponding diurnal temperature ranges in both winter and summer decrease. With increment in distance from the water body, additionally, the climatic effects of reservoir become weaker. The potential spatial zones of influences induced by the Three Gorges Project are limited to the distances of 0-8 km from the water body.