The Intergovernmental Panel on Climate Change (IPCC) conducts policyrelevant but not policy-prescriptive assessments of climate science. In this review, we engage with some of the key design features, achievements, and challenges that situate and characterize the IPCC as an intergovernmental organization that is tasked with producing global environmental assessments (GEAs). These include the pr...

Projected changes in emissions and climate will impact future air quality and related human and environmental health. In this work, an advanced online-coupled meteorology and chemistry model, the Weather Research and Forecasting Model with Chemistry (WRF/Chem), has been applied to the continental U.S. for current (2001–2010) and future (2046–2055) decades under four emission/ climate scenarios ...

The early Eocene “equable climate problem”, i.e. warm extratropical annual mean and above-freezing winter temperatures evidenced by proxy records, has remained as one of the great unsolved problems in paleoclimate. Recent progress in modeling and in paleoclimate proxy development provides an opportunity to revisit this problem to ascertain if the current generation of models can reproduce the p...

The uncompromising stance currently taken by the US in the international climate change regime is well known. While remaining a party to the United Nations Framework Convention on Climate Change (UNFCCC), and still taking the issue of climate change ‘very seriously’, the administration of George W. Bush has decided not to ratify the 1997 Kyoto Protocol. Since announcing its repudiation of the P...

This paper provides an overview of climatic changes that have been observed during the past century at certain high-elevation sites, and changes in a more distant past documented by a variety of climate-sensitive environmental indicators, such as tree-rings and alpine glaciers, that serve as a measure of the natural variability of climate in mountains over longer time scales. Detailed studies s...

Climate change has substantial impacts on public health and safety, disease risks and the provision of health care, with the poor being particularly disadvantaged. Management of the associated health risks and changing health service requirements requires adequate responses at local levels. Health-care providers are central to these responses. While climate change raises ethical questions about...

The paper is not intended for game theorists – unless they are interested in learning how their theories, and the theory of environmental games as developed in a forthcoming book, are being used for studying the current problem of climate change. Similarly for economists. In general, the presentation is addressed to those who have an interest in seeing how theory can shape policy in the area of...

Information theory provides a concise systematic framework for measuring climate consistency and sensitivity for imperfect models. A suite of increasingly complex physically relevant linear Gaussian models with time periodic features mimicking seasonal cycle are utilized to elucidate central issues that arise in contemporary climate science. These include the role of model error, the memory of ...

T he Earth’s climate is dominated by diverse and changeable natural processes over a wide range of time and space scales (e.g., Folland et al. 2001). This includes changes related to transient synoptic weather systems and to phenomena on much longer time scales, such as the quasibiennial oscillation (QBO) and El Niño–Southern Oscillation (ENSO) with time scales up to several years. Especially i...

Earth system climate sensitivity (ESS) is the long-term (>10³ year) response of global surface temperature to doubled CO₂ that integrates fast and slow climate feedbacks. ESS has energy policy implications because global temperatures are not expected to decline appreciably for at least 10³ year, even if anthropogenic greenhouse gas emissions drop to zero. We report provisional ESS estimates of ...