The earth's polar regions--the Arctic and Antarctic--are essential to maintaining the planet's climate as we know it. The vast expanses of ice and snow found at high latitudes help to cool the earth by reflecting incoming solar radiation, and the temperature gradient between the equator and the poles is a major driver of ocean and atmospheric currents, the pathways by which heat is distributed around the globe.

With global warming, these dynamic processes have caused temperatures in many polar locations to rise about twice as fast as the global average during the past few decades. As a result, polar ecosystems have already undergone significant physical changes, often to the detriment of these regions' inhabitants. For example, recent media coverage has focused on climate change's negative effects on Arctic polar bear populations.

Today, March 1, marks the launch of International Polar Year (IPY), a major scientific research initiative that will comprehensively explore the earth's Arctic and Antarctic regions. During the next two years, thousands of scientists from over sixty countries will study physical, biological, and social aspects of polar ecosystems, with particular concern for the impacts of global warming. The over 200 currently planned research projects will be coupled with outreach and education activities designed to communicate scientific findings to the public.

In 2005, Americans consumed 16.2 pounds (7.3 kg) of fish and shellfish per person, according to a recent report by the National Oceanic and Atmospheric Association (NOAA). Although this figure represents a slight (two percent) decrease in average per capita consumption from the previous year, seafood consumption trends, overall, have been steadily increasing--in 2001, per capita consumption rates were 14.8 pounds (6.7 kg) per person. This trend is particularly relevant in light of a growing U.S. population and recent studies that predict global fisheries may collapse by mid-century if they are not managed more sustainably.

Annual variations in Indonesia's climate are largely determined by the El Niño/Southern Oscillation (ENSO) system. However, extreme drought can also result from the cooling of sea surface temperatures near Sumatra caused by a similar ocean-atmosphere phenomenon--the Indian Ocean Dipole (IOD). These two systems and their past and present relationship to the Asian monsoon are examined in a recent study by Abram et al., reported in Nature. The scientists' findings reveal that drought frequency and duration in Indonesia can be expected to increase with global warming.

Sometime next year, the number of urban inhabitants worldwide will exceed the rural population for the first time in human history. Although urban areas only cover 0.4 percent of the planet's surface, city policies are critical to dictating future actions toward poverty reduction and global warming. Urbanization and the challenges and opportunities confronting the world's city populations are the focus of the latest edition of the Worldwatch Institute's flagship publication, State of the World 2007: Our Urban Future.

Seventy-five percent of waste generated by passengers of U.S. airlines and airports could be recycled or composted, according to a new study by the non-profit National Resources Defense Council (NRDC). However, average recycling rates of the airline industry were found to be around 20%, even lower than the national average (31%). While most U.S. airports and airlines have yet to embrace a rigorous recycling program, those that have are receiving great benefits--saving well over US$100,000 annually.

Seventy-five percent of Europe's population currently resides in urban areas. But the amount of land used per person has more than doubled in the past 50 years, indicative of a region-wide increase in urban sprawl. A new report by the European Environment Agency (EEA) provides key data and analyses of the root causes and extent of Europe's recent urban expansion. The report also discusses how better government coordination and controls can curb sprawl and limit negative environmental and social impacts.

The sandy beaches, rocky shorelines, water, and waves of coastal areas are perhaps most readily associated with recreation and natural beauty. Coastal ecosystems, however, have an economic value beyond their aesthetic benefit, supporting human lives and livelihoods through the provision of food and materials, nutrient cycling, waste processing, and other essential goods and services.

By one estimation, the combined global value of goods and services from coastal ecosystems is over US$12 trillion annually (1997 dollars; Costanza et al., 1997)--a figure larger than the United States' Gross Domestic Product in 2004. Yet many of these services are not explicitly priced in world markets, leaving governments, businesses, and individuals with few incentives to maintain them.

National and international efforts are not keeping pace with the spread of the global AIDS epidemic. At the end of 2006, an estimated 39.5 million people have HIV/AIDS, and that number continues to grow, according to the latest UNAIDS/WHO report.

Although several countries are making progress in reducing the number of new HIV infections, recent trends in AIDS data show a resurgence of HIV/AIDS in several regions. The report states that more focused and sustained prevention programs are needed, especially those that target specific groups, such as high-risk individuals and youth.

During the past half century, the world has lost some 20 percent of its coral reefs. More than half of remaining reefs could be gone in the next few decades due to the impacts of climate change and other human-caused stresses. A recent report published by the World Conservation Union (IUCN) and The Nature Conservancy states that there is still time to avert mass mortality of reefs, if concerted efforts to reduce stresses such as coastal pollution and overfishing are initiated immediately.