North Pacific Climate Variability and Arctic Sea Ice

Boreal winter North Pacific climate variability strongly influences North American hydroclimate and Arctic sea ice distribution in the marginal Arctic seas. Two modes of atmospheric variability explaining 53% of the variance in the Pacific Ocean sea level pressure (SLP) field are extracted and identified: the Pacific-North American (PNA) teleconnection and the North Pacific Oscillation/West Pacific (NPO/WP) teleconnection. The NPO/WP, a dipole in North Pacific SLP and geopotential heights, is affiliated with latitudinal displacements of the Asian Pacific jet and an intensification of the Pacific stormtrack. The North American hydroclimate impacts of the NPO/WP are substantial; its impact on Alaska, Pacific Northwest and Great Plains precipitation is more influential than both the PNA and the El Niño-Southern Oscillation (ENSO). The NPO/WP is also strongly associated with a contemporaneous extension of the marginal ice zone (MIZ) in the western Bering Sea and Sea of Okhotsk and MIZ retreat in the eastern Bering Sea. Wintertime climate variability also significantly impacts the distribution of Arctic sea ice during the subsequent summer months, due to the hysteretic nature of the ice cap. The North Atlantic Oscillation (NAO) is known for its effects on summer sea ice distribution; this study extends into the Pacific and finds that circulation anomalies related to Pacific sea surface temperature (SST) variability also strongly impact summer Arctic sea ice. The NAO and ENSO are related to sea ice decline in the Eastern Siberian Sea, where the linear trend since 1979 is 25% per decade. PDV affects sea ice in the eastern Arctic, a region which displays no linear trend since 1979. The low frequency of PDV variability and the persistent positive NAO during the 1980s and 1990s results in natural variability being aliased into the total linear trend in summer sea ice calculated from satellite-based sea ice concentration. Since 1979, natural variability accounts for 30% of the negative trend in the Pacific marginal sea and offsets sea ice loss forced by additional factors in the Greenland Sea. Contemporaneous atmospheric variability during the boreal summer is not related to the sea ice trend, but does influence sea ice distribution in individual summers

Disasters and Risk in Cities

The effects of climate-related disasters are often exacerbated in cities due to interactions with urban infrastructure systems, growing urban populations, cultures, and economic activities. Because the majority of the world’s population is currently living in cities –and with this share projected to increase in the coming decades– cities need to focus on improving responses to climate-related disasters such as heat waves, floods, and droughts. In a changing climate, a new decision-making framework is needed in order to manage emerging and increasing risks. This involves a paradigm shift away from attention to single climate hazards based on past events. The new paradigm requires integrated, system-based risk assessments and interventions that address current and future hazards throughout entire metropolitan regions.Fil: Gencer, Ebru. No especifíca;Fil: Folorunsho, Regina. No especifíca;Fil: Linkin, Megan. No especifíca;Fil: Wang, Xiaoming. No especifíca;Fil: Natenzon, Claudia Eleonor. No especifíca;Fil: Wajih, Shiraz. No especifíca;Fil: Mani, Nivedita. No especifíca;Fil: Esquivel, Maricarmen. No especifíca;Fil: Ali Ibrahim, Somayya. Columbia University; Estados Unidos. National Aeronautics and Space Administration; Estados UnidosFil: Tsuneki, Hori. No especifíca;Fil: Castro Diaz, Ivan Ricardo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Filosofía y Letras. Instituto de Geografía "Romualdo Ardissone"; ArgentinaFil: Leone, Mattia Federico. No especifíca;Fil: Panjwani, Dilnoor. No especifíca;Fil: Romero Lankao, Patricia. National Center for Atmospheric Research; Estados UnidosFil: Solecki, William. City University of New York; Estados Unido