Why Is the Climate Forcing of Sulfate Aerosols So Uncertain?

l. IntroductionAlthough the aerosol has been recognized as an important factor which has innuence onthe past, present and future climate for a long time, it still has much uncertainty in assessingits climate forcing. The direct radiative forcing of sulfate aerosols has been estimated rangingfrom --0.3 W/ m2 to --0.9 W/ m2 in recent publications (Charlson et al., l992, Kiehl andBriegleb l993; Taylor and Penner 1994, Boucher and Anderson l995, Kieh1 and Rodhe l995;Chuang et al., l997, Penne…     

Uncertain climate: An investigation into public scepticism about anthropogenic climate change

This study presents a detailed investigation of public scepticism about climate change in Britain using the trend, attribution, and impact scepticism framework of Rahmstorf (2004). The study found that climate scepticism is currently not widespread in Britain. Although uncertainty and scepticism about the potential impacts of climate change were fairly common, both trend and attribution scepticism were far less prevalent. It further showed that the different types of scepticism are strongly interrelated. Although this may suggest that the general public does not clearly distinguish between the different aspects of the climate debate, there is a clear gradation in prevalence along the Rahmstorf typology. Climate scepticism appeared particularly common among older individuals from lower socio-economic backgrounds who are politically conservative and hold traditional values; while it is less common among younger individuals from higher socio-economic backgrounds who hold self-transcendence and environmental values. The finding that climate scepticism is rooted in people's core values and worldviews may imply a coherent and encompassing sceptical outlook on climate change. However, attitudinal certainty appeared mainly concentrated in non-sceptical groups, suggesting that climate sceptical views are not held very firmly. Implications of the findings for climate change communication and engagement are discussed.     

多模式对四川一次强降水过程不确定性预报分析

本文就2008年“5.12”四川大地震后,5月25~26日四川盆地出现的一次强降水过程,比较分析成都区域中心运行的3个区域(GRAPES、AREM和MM5)模式降水预报情况以及各模式预报的物理量场和大气状况的演变,得到:模式就不同起报时间,对同一时间段的降水预报效果是不一样的,初始场获取的大气信息对预报有着重要作用;模式预报的降水落区与物理量的垂直时间演变密切相关;各模式大气初始场差异及随时间演变决定了各模式降水预报差异。      

The Uncertain Value of Perfect ENSO Phase Forecasts: Stochastic Agricultural Prices and Intra-Phase Climatic Variations

Climate and crop yield variability associated with El Niño—Southern Oscillation (ENSO) are now predictable within limits. This predictability suggests a potential to tailor agricultural management to mitigate impacts of adverse conditions and to take advantage of favorable conditions. However, improved climate predictions may benefit society only with parallel advances in our ability to use this knowledge. We show that the value that will accrue to any given actor from an ENSO phase forecast should be viewed not as a known number but instead as a random draw from a distribution, even when the forecast is always correct. Forecast value depends on the highly variable contexts in which forecasts are used. Randomness in forecast value has significant implications for choices made by forecasters, forecast users and policy makers. To show randomness, we estimate potential economic values of ENSO forecasts for agricultural producers based on two realistic assumptions: the crop prices farmers receive are uncertain; and within an ENSO phase, the actual climate is variable in ways that affect profits. The use of synthetic weather and crop price series, with crop simulation models, helps show the range and likelihood of climate forecast value.     

Bridging Political Expectations and Scientific Limitations in Climate Risk Management – On the Uncertain Effects of International Carbon Sink Policies*

Despite great advances in carbon cycle research during the past decade the climatic impact of terrestrial ecosystems is still highly uncertain. Although contemporary studies suggest that the terrestrial biosphere has acted as a net sink to atmospheric carbon during the past two decades, the future role of terrestrial carbon pools is most difficult to foresee. When land use change and forestry activities were included into the Kyoto Protocol in 1997, the requirements for scientific precision increased significantly. At the same time the political expectations of carbon sequestration as climate mitigation strategy added uncertainties of a social kind to the study of land-atmosphere carbon exchange that have been difficult to address by conventional scientific methods. In this paper I explore how the failure to take into account the effects of direct human activity in scientific projections of future terrestrial carbon storage has resulted in a simplified appreciation of the risks embedded in a global carbon sequestration scheme. I argue that the social limits to scientific analysis must be addressed in order to accommodate these risks in future climate governance and to enable continued scientific authority in the international climate regime.