The new focus in Science Magazine Vol. 311 gives insight on the startling amounts of ice slipping into the sea, which has taken glaciologists by surprise. They now fear that this century's greenhouse emissions could be committing the world to a catastrophic sea-level rise.
Over the past century, atmospheric methane (CH4) rose dramatically before leveling off in the late 1990s. The processes controlling this trend are poorly understood, limiting confidence in projections of future CH4. The MOZART-2 global tropospheric chemistry model qualitatively captures the observed CH4 trend (increasing in the early 1990s and then leveling off) with constant emissions. From 1991–1995 to 2000–2004, the CH4 lifetime versus tropospheric OH decreases by 1.6%, reflecting increases in OH and temperature. The rise in OH stems from an increase in lightning NOx as parameterized in the model. A simulation including annually varying anthropogenic and wetland CH4 emissions, as well as the changes in meteorology, best reproduces the observed CH4 distribution, trend, and seasonal cycles. Projections of future CH4 abundances should consider climate-driven changes in CH4 sources and sinks.
Understanding the North American carbon budget, both sources and sinks, is critical to the U.S. Climate Change Science Program goal of providing the best possible scientific information to support public discussion, as well as government and private sector decision making, on key climate-related issues. In response, the First State of the Carbon Cycle Report (SOCCR) was prepared and provides a synthesis, integration and assessment of the current knowledge of the North American carbon budget and its context within the global carbon cycle. The Report is organized as a response to questions about the North American carbon budget relevant to carbon management policy options and a broad range of stakeholder groups interested in knowledge of carbon cycling in North America and of how such knowledge might be used to influence or make decisions. The questions were identified through early and continuing dialogue with these stakeholder groups, including scientists, decision makers in the public sector (Federal, State, and local governments), the private sector (carbon-related industry, including energy, transportation, agriculture, and forestry sectors; and climate policy and carbon management interest groups), the international community, and the general public. The draft version of the SOCCR report is now available. The North American Carbon Budget and Implications for the Global Carbon Cycle report addresses carbon emissions; natural reservoirs and sequestration; rates of transfer; the consequences of changes in carbon cycling on land and the ocean; effects of purposeful carbon management; effects of agriculture, forestry, and natural resource management on the carbon cycle; and the socio-economic drivers and consequences of changes in the carbon cycle.
section1=Climate section2=Publications Recent Study Suggests Decreased Cloud Cover Over China Dale P. Kaiser and Yun Qian. 2006.
Work performed by Yun Qian, CDIAC’s Dale Kaiser, and others which appeared in a recent issue of Geophysical Research Letters suggests China has experienced significant decreases in cloud cover over the past fifty years. The work was made possible by newly available data from an extended weather station network in China. Over the past half of the Twentieth century, the total cloud cover and low cloud cover have decreased 0.88% and 0.33% each decade, respectively. Meanwhile, both solar radiation and pan evaporation have decreased in China. By combining these results, there is speculation that increased air pollution may have produced a fog-like haze that reflected or absorbed radiation from the sun resulting in less solar radiation reaching the surface. The increasing amount of air pollution is a result of China’s increasing population. Emissions from the consumption of fossil fuels has increased about 9-fold in China since the 1950s and such a dramatic increase in the emissions of pollutants can result in a significant increase in anthropogenic aerosol loading in the atmosphere and affect the climate and hydrological cycle. Researchers have found that the aerosols are forcing more radiation into the atmosphere, which can result in dimming and cause a variety of problems. These problems include cooling of the surface, stabilizing the atmosphere, and reducing evaporation, which may lead to changes in the regional climate and hydrological cycle.
section1=Emissions section2=Publications The annual cycle of fossil-fuel carbon dioxide emissions in the United States Dr. T. J. Blasing et al. 2005.
Time-series of estimated monthly carbon dioxide emissions from consumption of coal, petroleum and natural gas in the United States from 1981 to 2002 have been derived from energy consumption data. This paper explains how these monthly carbon emission estimates should be helpful in gaining a better understanding of the carbon cycle.