River Plate 1999

[Haziel Barbour]

Thereis ample evidence of climate variability at a wide range of time scalesall over Latin America, from intraseasonal to long term. In many subregionsof Latin America, this variability in climate normally is associated with phenomenathat already produce impacts with important socioeconomic and environmentalconsequences that could be exacerbated by global warming and associated climatechange. Signals that can be related to variability and/or change in climateconditions for Latin America have been identified in some of the analyses performedby researchers in the region, particularly for streamflow, precipitation, temperature,glacier oscillations, general circulation, and extreme events. Estimations ofpotential future climate conditions are based on climate change scenarios studiesdeveloped for some subregions of Latin America.

Glaciers in Latin America have receded dramatically in the past decades, andmany of them have disappeared completely (Williams and Ferrigno, 1998). In 18glaciers in the Peruvian Andes, mass balances since 1968 and satellite imagesshow a reduction of more than 20% of the glacial surface, corresponding to 11,300million m3 of ice (Morales-Arnao, 1969a,b; INAGGA-CONAM, 1999). Significantreductions also have occurred in southern Chile and Argentina (e.g., glacierSarmiento) (Basso, 1997). Deglaciation may have contributed to observed negativetrends in streamflows in that region (Morales-Arnao, 1999). For rivers in aridlands in northwest Peru and northeast and southeastern Brazil, significant negativetrends also have been detected, but these variations seem to be related to humanwater management for irrigation purposes and increases in agricultural areas,rather than climate-induced changes (INRENA, 1994; Marengo, 1995; Marengo etal., 1998).

Between 20S and 40S, precipitation around the Andes occurs mainlyduring the winter. Snow accumulates in the high parts of the cordillera andmelts during the summer, becoming the main source of water for rivers in theregion. Agricultural activities in central Chile and the Argentinean centralwestern plains are maintained through irrigation. Therefore, it may be saidwith high confidence that fluctuations in winter precipitation have a strongsocioeconomic impact in the region.

In northwestern Mexico, there is a tendency for more winter precipitation,which has resulted in positive trends in river water levels. However, alongwith more intense winter precipitation, interannual climate variability hasincreased (Magaa and Conde, 2000). On the other hand, some parts ofsouthern Mexico and Central America exhibit positive or negative rainfall trends,depending on the orientation of the catchment (Aparicio, 1993; IPCC, 1996; Juregui,1997; TAR WGI Chapter 3).

For Nicaragua, rainfall analysis for 1961-1995 showed negative trendsin the north and northwest parts of the country. A systematic increment wasdetected on the Caribbean coast, and almost no variation was found along thecentral and the Pacific coastal regions (MARENA, 2000).

In Colombia, weak rainfall trends have been observed for the period 1955-1995,with no preferred sign at a regional level. For central Colombia, rainy seasonshave been occurring earlier in recent years than 25 years ago (Mesa et al.,1997). Trends in Colombian river streamflow are mixed, but the main river catchmentssuch as the Cauca and Magdalena Rivers exhibit decreasing trends. Deforestationcould account for such decreasing trends in river discharges (Poveda and Mesa,1997).

For the Amazon region, Marengo et al. (2000) have identified multidecadalvariations in rainfall in northern and southern portions of the basin, withopposite tendencies. Perhaps the most important finding is the presence of periodswith relatively wetter or drier conditions that are more relevant than any unidirectionaltrends themselves. For instance, the period 1950-1976 was regionally wetin northern Amazonia, but since 1977 the region has been drier. This drynessdoes not seem to be related to regional deforestation (see Marengo et al.,1998; Marengo and Nobre, 2000; TAR WGI Chapter3). Similarly, streamflow series in Amazonian rivers also exhibit multidecadalvariations; they do not display significant unidirectional trends (Richey etal., 1989; Marengo, 1995).

In northeast Brazil, multidecadal variations in atmospheric circulation overthe tropical Atlantic have been linked to similar time-scale variations in rainfallover the region (Hastenrath and Greischar, 1993; Nobre and Shukla, 1996; Wagner,1996). On longer time scales, rainfall in northern northeast Brazil exhibitsweak positive trends that are consistent with changes in decadal changes incirculation described in Wagner (1996).

In subtropical Argentina, Paraguay, and Brazil, precipitation exhibits a long-termchange, with a sharp increase in the period 1956-1990 after a dry periodalong 1921-1955 (Castaeda and Barros, 1996). In the Pampa region,there is a positive trend in precipitation during the period 1890-1984.This increase in annual rainfalls was accompanied by a relative increase inprecipitation during the spring and summer (Penalba and Vargas, 1996; Hoffmanet al., 1997; Krepper and Sequeira, 1998). At high elevations in northwestArgentina, paleoclimatic records suggest an increase in precipitation in thepast 200 years (Villalba et al., 1997). In the same region, as well asin Bolivia and southeast Peru, records show that the 17th-century climate waswetter and less variable (fewer floods and droughts ), whereas the 18th centurywas highly unstable, with a large amplitude in the annual cycle and recurrentwet and dry periods (Prieto and Herrera, 1992).

Variations in precipitation in Latin America have a strong effect on runoffand streamflow, which also are affected by melting of glaciers and snow. Basedon available information, there is evidence that these variations and theirsign depend on the geographical subregion under consideration.

A Press report from Atlanta, dated 17 January, states: Three former officialsof LCP Chemicals-Georgia Inc. have been convicted in what federal authoritieshave called one of the worst cases of corporate pollution in the USA. A USDistrict Court jury found the three guilty of illegally releasing and storinghazardous materials and endangering workers at LCP's plant in Brunswick, GA,which was closed in 1994. The jury deliberated for just over four hours on thenight of Friday, 15 January, before finding Christian A. Hansen Jr guilty on all41 counts and his son Randall W. Hansen guilty on 34 counts. The elder Hansen,who is from New Jersey, was chief executive officer of the Hanlin Group Inc.,the parent company of now bankrupt LCP, and his son, a Virginia resident, waschief operating officer. The jury found Alfred R. Taylor of Brunswick, a formermanager of the plant, guilty on 20 counts. After receiving the verdicts, USMagistrate James E. Graham released all three defendants and gave them a week topost a $50,000 secured bond. No sentencing date was set. The charge of recklessendangerment in exposing plant employees to improperly stored hazardousmaterials carries a maximum 15-year term. Authorities said the plant dischargedpollutants including mercury, chlorine and caustic soda into the environment atthe 550-acre site in the marshes near Brunswick. They said the officials storedhazardous wastes without a permit, endangered employees and others with theunlawful storage of hazardous chemicals, and conspired to violate federalanti-pollution laws. The LCP plant has been declared a Superfund site by the USEnvironmental Protection Agency, which has been conducting a clean-up.

Emergency workers contained more than 300 gallons of fuel which spilled intoNew Bedford harbour after fvs Alyssa & Zuchay (78gt, built 1975) andCalifornia (58gt, built 1953), both 61ft in length, sank yesterdayevening. According to Coast Guard spokesman Lt Paul King, the vessels sank offTwin Pier, spilling fuel and waste oil into the water. Officials learned of thespill around 22.30 hrs, King said. A clean-up crew had contained the spilltoday, and about 5,000 gallons of diesel fuel still on board the vessels hadapparently not spilled, King said. Workers will try to retrieve the vesselstoday, overseen by the Coast Guard Marine Safety Office of Providence. It wasnot immediately known what caused the vessels to sink, or the extent of damagecaused by the spill, King said.A salvage meeting took place regarding whataction to take regarding salving the vessels. Pollution cleanup is due to becompleted by 5 January.8 January 1999 - Press release from CoastGuard, Boston, states: Providence, RI: fvs Alyssa & Zachary and Californiasank together at the Twin Pier in New Bedford, MA, on the evening of Sunday 5January, releasing approximately 400 gallons of diesel fuel and waste oil intoNew Bedford harbour. Both vessels are boomed off and their fuel vents wereplugged by divers yesterday. The cause of the sinkings is under investigation bythe Coast Guard. The owners of the vessels have been identified and will bepaying for the clean-up and salvage. The response is being co-ordinated by theCoast Guard Marine Safety Office in Providence, the Massachusetts Department ofEnvironmental Protection, and representatives from both vessels. Plans forsalving the vessels were discussed at a meeting this morning. Two cranes will bebrought to the Twin Pier from Fairhaven today and will set up to raise bothvessels tomorrow.

Following received from Fairplay, dated today: Mv Pallas is sinkinginto the sands off the German North Sea island of Amrum. The main deck andforecastle of the buckled hull are already under water. A German salvage expertwarned that further efforts to remove the ship would cause more damage to theenvironment than leaving it in its current position. Dutch salvors have pumpedthe oil from the wreck, leaving a minimum amount in the tanks, but a finaldecision as to removal or otherwise will not be taken by German authoritiesuntil the winter has passed. Salvage operations were severely impaired by winterstorms, and salvors initially focused their efforts on removing oil from thevessel. It has now been suggested that the vessel has been aground for so longthat it will no longer be possible to salvage her.

3a8082e126