Global warming and carbon dioxide through sciences

Increased atmospheric CO(2)-concentration is widely being considered as the main driving factor that causes the phenomenon of global warming. This paper attempts to shed more light on the role of atmospheric CO(2) in relation to temperature-increase and, more generally, in relation to Earth's life through the geological aeons, based on a review-assessment of existing related studies. It is pointed out that there has been a debate on the accuracy of temperature reconstructions as well as on the exact impact that CO(2) has on global warming. Moreover, using three independent sets of data (collected from ice-cores and chemistry) we perform a specific regression analysis which concludes that forecasts about the correlation between CO(2)-concentration and temperature rely heavily on the choice of data used, and one cannot be positive that indeed such a correlation exists (for chemistry data) or even, if existing (for ice-cores data), whether it leads to a "severe" or a "gentle" global warming. A very recent development on the greenhouse phenomenon is a validated adiabatic model, based on laws of physics, forecasting a maximum temperature-increase of 0.01-0.03 degrees C for a value doubling the present concentration of atmospheric CO(2). Through a further review of related studies and facts from disciplines like biology and geology, where CO(2)-change is viewed from a different perspective, it is suggested that CO(2)-change is not necessarily always a negative factor for the environment. In fact it is shown that CO(2)-increase has stimulated the growth of plants, while the CO(2)-change history has altered the physiology of plants. Moreover, data from palaeoclimatology show that the CO(2)-content in the atmosphere is at a minimum in this geological aeon. Finally it is stressed that the understanding of the functioning of Earth's complex climate system (especially for water, solar radiation and so forth) is still poor and, hence, scientific knowledge is not at a level to give definite and precise answers for the causes of global warming.     

Interspecies and interregional comparisons of the chemistry of PAHs and trace elements in mosses Hylocomium splendens (Hedw.) B.S.G. and Pleurozium schreberi (Brid.) Mitt. from Poland and Alaska

Comparative biogeochemical studies performed on the same plant species in remote areas enable pinpointing interspecies and interregional differences of chemical composition. This report presents baseline concentrations of PAHs and trace elements in moss species Hylocomium splendens and Pleurozium schreberi from the Holy Cross Mountains (south-central Poland) (HCM) and Wrangell–Saint Elias National Park and Preserve (Alaska) and Denali National Park and Preserve (Alaska). Total PAH concentrations in the mosses of HCM were in the range of 473–2970 μg kg^?1 (dry weight basis; DW), whereas those in the same species of Alaska were 80–3390 μg kg^?1 DW. Nearly all the moss samples displayed the similar ring sequence: 3 > 4 > 5 > 6 for the PAHs. The 3 + 4 ring/total PAH ratios show statistically significant differences between HCM (0.73) and Alaska (0.91). The elevated concentrations of PAHs observed in some sampling locations of the Alaskan parks were linked to local combustion of wood, with a component of vehicle particle- and vapor-phase emissions. In HCM, the principal source of PAH emissions has been linked to residential and industrial combustion of coal and vehicle traffic. In contrast to HCM, the Alaskan mosses were distinctly elevated in most of the trace elements, bearing a signature of the underlying geology. H. splendens and P. schreberi showed diverse bioaccumulative capabilities of PAHs in all three study areas.     

Exposure of PM2.5 and EC from diesel and gasoline vehicles in communities near the Ports of Los Angeles and Long Beach,California

The Ports of Los Angeles and Long Beach are the entry point for almost half of all cargo containers entering the United States. The use of diesel trucks to move Port-related goods has raised significant public health concerns associated with black carbon and other air pollutants. It is difficult to reliably estimate people's exposure to vehicle-related pollutants due to the narrow impact zone of traffic, usually within 200–300 m downwind of major roadways. Previous studies suffer from the lack of traffic count data on surface streets and the lack of neighborhood-level population data. We examined seasonal and annual average exposures of particulate matter less than 2.5 μm (PM_2.5) and elemental carbon (EC) at a neighborhood scale for communities heavily impacted by diesel trucks near these ports. We assembled a traffic-activity database that distinguishes gasoline and diesel vehicles on both freeways and surface streets, by consolidating information from several sources, including our own field measurements. The CALINE4 model was used to estimate residential exposure of the study population to PM_2.5 and EC. Parcel property data were used to allocate Census block group (BG) population to increase spatial resolution. The annual average PM_2.5 and EC exposure due to local traffic was 3.8 and 0.4 μg m^?3, respectively. On average, surface streets contributed a little more than freeways (55% vs. 45% for EC and 57% and 43% for PM_2.5). Light-duty vehicles contributed significantly more than heavy-duty trucks for PM_2.5 (61% vs. 39%), but slightly less than heavy-duty trucks for EC (49% vs. 51%). Community mean population exposure was similar using parcel, census block, and BG population data, but extreme values and standard deviations varied significantly at different spatial resolutions. The intake fraction for the study population was in the range of 1.0–2.2 × 10^?5 by vehicle type, roadway type, and season.     

Retrieval of Carbon monoxide profiles over Indian region using MOPITT data

Vertical profiles of carbon monoxide (CO) over the Indian region have scarcely been monitored. Satellite sensor, Measurement Of Pollution In The Troposphere (MOPITT) provides profiles of CO using a global retrieval scheme, which converts measured radiances to CO mixing ratios. In this study we have developed a regional retrieval scheme, valid over the Indian region, which employs Line-By-Line (LBL) calculations over a tropical model atmosphere to generate a Look-Up-Table (LUT) forward model function and uses a regional a priori dataset of CO along with seasonally variable emissivity to invert the MOPITT radiances to CO profiles. This baseline study provides an approach to optimizing retrievals for specific regional applications. A case study was carried out over a forest fire prone region in Northern India from February to April 2005 to validate the retrieval algorithm. The results are in agreement with the fire maps generated from MODerate resolution Imaging Spectro-radiometer (MODIS). The shape of the CO profiles over the region matches quite well with the vertical structure of CO during the INDOEX campaign, especially during the polluted month of April. Inter-comparisons with the MOPITT data product indicate some discrepancies in the lower troposphere, especially during the forest fire season. Future studies with in-situ measurements may be able to diagnose these disparities.     

Achieving Conservation Goals in Managed Forests of the Southeastern Coastal Plain

Managed forests are a primary land use within the Coastal Plain of the southern United States. These forests are generally managed under standards, guidelines, or regulations to conserve ecosystem functions and services. Economic value of commercial forests provides incentives for landowners to maintain forests rather than convert them to other uses that have substantially reduced environmental benefits. In this review, we describe the historical context of commercial forest management in the southern United States Coastal Plain, describe how working forests are managed today, and examine relationships between commercial forest management and maintenance of functional aquatic and wetland systems and conservation of biological diversity. Significant challenges for the region include increasing human population and urbanization and concomitant changes in forest area and structure, invasive species, and increased interest in forest biomass as an energy feedstock. Research needs include better information about management of rare species and communities and quantification of relationships between ecosystem attributes and forest management, including biomass production and harvest. Incentives and better information may help commercial forest managers in the Coastal Plain more efficiently contribute to landscape-scale conservation goals.     

Potential Mortality Effects of Off-Highway Vehicles on the Flat-Tailed Horned Lizard (<Emphasis Type="Italic">Phrynosoma mcallii</Emphasis>): A Manipulative Experiment

Southern California desert public lands receive especially high levels of off-highway recreation due to large population centers nearby and popular riding environments such as sand dunes. Controversy has developed over the flat-tailed horned lizard (Phrynosoma mcallii), previously a candidate for listing under the Endangered Species Act. Some evidence suggests lower lizard abundance in areas of higher recreational use than in areas with low or no use. We designed a manipulative experiment to ensure maximum inference in evaluating the direct impact of recreational riding of off-highway vehicles on lizards. Thirty-six lizards, in situ, were treated with an off-highway vehicle treatment during hibernation season in three treatment groups: high impact, low impact, and control. Treatments consisted of timed riding by off-highway vehicles. In all treatment groups survival was 100%, despite hibernation of lizards at very shallow depths. Consequently, indirect effects of off-highway vehicles deserve increased attention. The relative importance of direct versus indirect (i.e., degradation of lizard habitat) impacts caused by off-highway vehicles remains unknown. These indirect effects may include the altering of vegetation, substrate, and prey. We recommend that a manipulative approach be adopted to investigate these possibilities.     

An integrated approach to assess broad-scale condition of coastal wetlands—the Gulf of Mexico Coastal Wetlands pilot survey

The Environmental Protection Agency (EPA) and U.S. Geological Survey (USGS) initiated a two-year regional pilot survey in 2007 to develop, test, and validate tools and approaches to assess the condition of northern Gulf of Mexico (GOM) coastal wetlands. Sampling sites were selected from estuarine and palustrine wetland areas with herbaceous, forested, and shrub/scrub habitats delineated by the US Fish and Wildlife Service National Wetlands Inventory Status and Trends (NWI S&T) program and contained within northern GOM coastal watersheds. A multi-level, stepwise, iterative survey approach is being applied to multiple wetland classes at 100 probabilistically-selected coastal wetlands sites. Tier 1 provides information at the landscape scale about habitat inventory, land use, and environmental stressors associated with the watershed in which each wetland site is located. Tier 2, a rapid assessment conducted through a combination of office and field work, is based on best professional judgment and on-site evidence. Tier 3, an intensive site assessment, involves on-site collection of vegetation, water, and sediment samples to establish an integrated understanding of current wetland condition and validate methods and findings from Tiers 1 and 2. The results from this survey, along with other similar regional pilots from the Mid-Atlantic, West Coast, and Great Lakes Regions will contribute to a design and implementation approach for the National Wetlands Condition Assessment to be conducted by EPA’s Office of Water in 2011.     

Simulated fate and transport of metolachlor in the unsaturated zone, Maryland, USA

An unsaturated-zone transport model was used to examine the transport and fate of metolachlor applied to an agricultural site in Maryland, USA. The study site was instrumented to collect data on soil-water content, soil-water potential, ground water levels, major ions, pesticides, and nutrients from the unsaturated zone during 2002-2004. The data set was enhanced with site-specific information describing weather, soils, and agricultural practices. The Root Zone Water Quality Model was used to simulate physical, chemical, and biological processes occurring in the unsaturated zone. Model calibration to bromide tracer concentrations indicated flow occurred through the soil matrix. Simulated recharge rates were within the measured range of values. The pesticide transport model was calibrated to the intensive data collection period (2002-2004), and the calibrated model was then used to simulate the period 1984 through 2004 to examine the impact of sustained agricultural management practices on the concentrations of metolachlor and its degradates at the study site. Simulation results indicated that metolachlor degrades rapidly in the root zone but that the degradates are transported to depth in measurable quantities. Simulations indicated that degradate transport is strongly related to the duration of sustained use of metolachlor and the extent of biodegradation.     

Options for management of municipal solid waste in New York City: a preliminary comparison of health risks and policy implications

Landfill disposal and waste-to-energy (WTE) incineration remain the two principal options for managing municipal solid waste (MSW). One critical determinant of the acceptability of these options is the different health risks associated with each. In this analysis relying on published data and exposure modeling, we have performed health risk assessments for landfill disposal versus WTE treatment options for the management of New York City's MSW. These are based on the realistic scenario of using a waste transfer station (WTS) in Brooklyn and then transporting the untreated MSW by truck to a landfill in Pennsylvania or using a WTE facility in Brooklyn and then transporting the resultant ash by truck to a landfill in Pennsylvania. The overall results indicate that the individual cancer risks for both options would be considered generally acceptable, although the risk from landfilling is approximately 5 times greater than from WTE treatment; the individual non-cancer health risks for both options would be considered generally unacceptable, although once again the risk from landfilling is approximately 5 times greater than from WTE treatment. If one considers only the population in Brooklyn that would be directly affected by the siting of either a WTS or a WTE facility in their immediate neighborhood, individual cancer and non-cancer health risks for both options would be considered generally acceptable, but risks for the former remain considerably higher than for the latter. These results should be considered preliminary due to several limitations of this study such as: consideration of risks only from inhalation exposures; assumption that only volume and not composition of the waste stream is altered by WTE treatment; reliance on data from the literature rather than actual measurements of the sites considered, assuming comparability of the sites. However, the results of studies such as this, in conjunction with ecological, socioeconomic and equity considerations, should prove useful to environmental managers, regulators, policy makers, community representatives and other stakeholders in making sound and acceptable decisions regarding the optimal handling of MSW.