The challenge of identifying greenhouse gas-induced climatic change

Meeting the challenge of identifying greenhouse gas-induced climatic change involves three steps. First, observations of critical variables must be assembled, evaluated, and analyzed to determine that there has been a statistically significant change. Second, reliable theoretical (model) calculations must be conducted to provide a definitive set of changes for which to search. Third, a quantitative and statistically significant association must be made between the projected and observed changes to exclude the possibility that the changes are due to natural variability or other factors. This paper provides a qualitative overview of scientific progress in successfully fulfilling these three steps

Gulf Coast assessment overview/charge to the workshop

There are several reasons that the U. S. Global Change Research Program (USGCRP) has initiated the U.S. National Assessment: The Potential Consequences of Climate Variability and Change. The reasons all revolve around answering questions posed in Washington by members of Congress on behalf of their constituents as to why climate change concerns them. This workshop is part of the process for getting better answers to these questions. This paper briefly reviews the science of climate change and the human influence on climate change, discusses future climate change, and considers national and international perspectives on global change. It discusses the potential for mitigation of climate change and the need to cope with climate change. The author explains the U.S. National Assessment

The Environmental Effects of Nuclear War

Substantial environmental disruption will significantly add to the disastrous consequences caused by the direct thermal, blast, and radiological effects brought on by a major nuclear war. Local fallout could cover several percent of the Northern Hemisphere with potentially lethal doses. Smoke from post-nuclear fires could darken the skies and induce temperature decreases of tens of degrees in continental interiors. Stratospheric ozone could be significantly reduced due to nitric oxide injections and smoke-induced circulation changes. The environmental effects spread the consequences of a nuclear war to the world population, adding to the potentially large disruptive effects a further reason to avoid such a catastrophe. 27 refs., 4 figs

Climate Change: The Evidence Mounts Up

This article was published in Nature and summarized the presentations of a six-day symposium held 3-8 July 1995 on Climate Variability and Forcing over the past mellennium. Our present climate is unusually warm, and the pattern of warming over the past century strongly suggests an anthropogenic influence from greenhouse gas and sulphate aerosols. That was the message emerging from a week-long symposium examining climate variability over the past 1,000 years, which brought together results from a growing array of observational techniques, analyses of natural records and model results

National assessment of the consequences of climate change for the United States

The US Global Change Research Program (USGCRP) is initiating a national assessment of the consequences of climate change and climate variability for the United States and the significance of these consequences for its people

National Assessment of the Potential Consequences of Climate Variability and Change for the United States

The first U.S. National Assessment of the PotentialConsequences of Climate Variability and Change for theUnited States is being conducted under the auspices of theU.S. Global Change Research Program (USGCRP). TheUSGCRP was established through the Global ChangeResearch Act of 1990 (P.L. 101-606) and mandatedthrough the statute with the responsibility to undertakeperiodic scientific assessments of the potentialconsequences of global change for the United States. Thegoal of the National Assessment is to analyze andevaluate what is known about the potential consequencesof climate variability and change for the nation in thecontext of other pressures on the public, the environment,and the nation\u27s resources. The conduct of the nationalassessment process will involve a broad spectrum ofstakeholders from state, local, tribal, and Federalgovernments; business; labor; academia; non-profitorganizations; and the general public. The assessmentwill link research by scientists to specific needs of thestakeholders, and will provide planners, managers,organizations, and the public with the information neededto increase resilience to climate variability and cope withclimate change. The national assessment will becomprised of three components: (1) National synthesis,(2) Sectoral analyses (agriculture, forestry, waterresources, human health, and the coastal zone), and(3) Regional analyses. To facilitate comparison,integration, and synthesis of each of the assessmentcomponents, all regional, sectoral, and synthesis analyseswill use a common set of scenarios for climate change and changes in socio-economic conditions. Specific responsibilities have been defined for oversight of the components of the national assessment and forcoordination activities. A National Assessment SynthesisTeam (NAST) will provide overall intellectual oversightof the national assessment process and has responsibilityfor the development of the Synthesis Report. A NationalAssessment Working Group under the auspices of theUSGCRP has lead responsibility for organizing andsponsoring the sectoral analyses and oversight andcoordination responsibilities for regional analyses. ANational Assessment Coordination Office has beenestablished to facilitate coordination of the entire nationalassessment process. The National Assessment SynthesisReport is targeted for completion by January 1, 2000, andis intended to satisfy the mandate for an assessmentdefined in P.L. 101-606 and serve as part of the U.S.contribution to the IPCC Third Assessment Report

IAMAS: a century of international cooperation in atmospheric sciences

The International Association of Meteorology and Atmospheric Sciences (IAMAS) was founded in 1919 as the Section of Meteorology of the International Union of Geodesy and Geophysics (IUGG). Significant advances over human history, particularly during the 19th century, in the gathering, communication, assembly and analysis of observations of the changing weather and in theoretical understanding of the fundamental physical relationships and processes governing atmospheric circulation had been driven by the need for improved weather and climate forecasts to support the expansion of global trade, better public warnings of extreme weather, and safer and more effective military operations. Since its foundation, in parallel and cooperation with intergovernmental development under the auspices of what is now the World Meteorological Organization (WMO), IAMAS and its 10 international commissions have provided the international organizational framework for the convening of the general and scientific assemblies and other meetings that bring together expert scientists from around the world to further advance scientific understanding and prediction of the behaviour of the atmosphere and its connections to and effects on other components of the Earth's intercoupled geophysical system.</p

Mitigation of short-lived greenhouse gases as the foundation for a fair and effective climate compromise between China and the West

Short-lived greenhouse gases that also contribute to air pollution are playing a major role in global warming. Black carbon alone is likely the second or third most important climate forcing agent. The short atmospheric lifetime of these pollutants means that, unlike CO2, reducing emissions produces a decrease in atmospheric concentration and a reduction of the radiative forcing that drives climate change. Black carbon and tropospheric ozone also have large negative effects at the regional and local level contributing substantially to indoor and urban air pollution and the formation of Atmospheric Brown Clouds that disrupt regional climate. Moreover, technologies to reduce emissions are available, cost-effective, and have already been widely deployed in developed countries. Reducing these short-lived greenhouse gases is therefore a mitigation pathway for industrializing countries that is both appropriate to their level of development and highly climatically effective. It is also consistent with both responsibility and capability fairness principles, both of which play important roles in the international climate regime. As such, it offers a way out of the current deadlock between developed and developing countries in which each group asks for more substantial emissions reduction commitments from the other before taking action. China, as the world’s largest black carbon emitter, should push for substantial CO2 mitigation commitments from the developed countries in return for aggressive action to reduce its own soot emissions. This action is consistent with China’s own development strategy and would contribute substantially to the mitigation of climate change

Sampling fossil floras for the study of insect herbivory: how many leaves is enough?

Despite the great importance of plant–insect interactions to the functioning of terrestrial ecosystems, many temporal gaps exist in our knowledge of insect herbivory in deep time. Subsampling of fossil leaves, and subsequent extrapolation of results to the entire flora from which they came, is practiced inconsistently and according to inconsistent, often arbitrary criteria. Here we compare herbivory data from three exhaustively sampled fossil floras to establish guidelines for subsampling in future studies. The impact of various subsampling routines is evaluated for three of the most common metrics of insect herbivory: damage type diversity, nonmetric multidimensional scaling, and the herbivory index. The findings presented here suggest that a minimum fragment size threshold of 1&thinsp;cm2 always yields accurate results and that a higher threshold of 2&thinsp;cm2 should yield accurate results for plant hosts that are not polyphyletic form taxa. Due to the structural variability of the plant hosts examined here, no other a priori subsampling strategy yields consistently accurate results. The best approach may be a sequential sampling routine in which sampling continues until the 100 most recently sampled leaves have caused no change to the mean value or confidence interval for damage type diversity and have caused minimal or no change to the herbivory index. For nonmetric multidimensional scaling, at least 1000&thinsp;cm2 of leaf surface area should be examined and prediction intervals should be generated to verify the relative positions of all points. Future studies should evaluate the impact of subsampling routines on floras that are collected based on different criteria, such as angiosperm floras for which the only specimens collected are those that are at least 50&thinsp;% complete.</p