Hydropower, also known as hydroelectric power, is the use of water to produce power. Harnessing water to perform work has been going on for thousands of years. The Greeks used waterwheels for grinding wheat into flour more than 2000 years ago. Besides grinding flour, the power of the water was used to saw wood and to power textile mills and manufacturing plants. This article looks briefly at how hydropower plant began, why it is considered renewable energy technology, the parts of a hydropower plant, types of turbines and when they are used, and what research and development is occurring. (more…)

Earth’s climate is a complex system of interacting natural components. These components include the atmosphere, the ocean, and the continental ice sheets. Living things on earth—or, the biosphere—also constitute an important component of the climate trends system.

Numerous factors influence Earth’s climate system, some of them natural. For example, the slow drift of continents that takes place over millions of years, a process known as plate tectonics, influences the composition of the atmosphere through its impact on volcanic activity and surface erosion. (more…)

Scientists study Earth’s climate not just from observation but also from a theoretical perspective. Modern-day climate models successfully reproduce the key features of Earth’s climate, including the variations in wind patterns around the globe, the major ocean current systems such as the Gulf Stream, and the seasonal changes in temperature and rainfall associated with Earth’s annual revolution around the sun. The models also reproduce some of the more complex natural oscillations of the climate system. Just as the atmosphere displays random day-to-day variability that we term “weather,” the climate system produces its own random variations, on timescales of years. (more…)

Addressing global warming, however, is a highly complex and daunting endeavor. Many climate experts have urged the world to stabilize greenhouse gas concentrations in the atmosphere around 450 to 550 parts per million (ppm)—that is, no more than 450 to 550 units of greenhouse gases for every million units of air in the earth’s atmosphere. This approach, experts say, could keep average global temperatures at no more than 3.6° Fahrenheit (2° Celsius) above preindustrial levels, which could avoid some of the worst, irreversible consequences of climate change. (more…)

Nuclear engineers work in conjunction with health physicists to assure that all activities involving radiation exposure to nuclear power plant workers or to the public are kept well below the U.S. requirements stated in Title 10, Part 20 of the Code of Federal Regulations (10 CFR 20). In fact, the current industry practice is to apply the ALARA (‘‘as low as reasonably achievable’’) principle to every exposure-related activity. To this end, nuclear engineers have been widely successful in designing nuclear plants that limit the dose to the public. (more…)

Still hotly debated by some, human-induced global warming is now accepted in the scientific community. Earth’s average yearly temperature is getting steadily warmer; sea levels are rising due to melting ice caps; and the resulting impact on ocean life, wildlife, and human life is already evident. The human-induced buildup of greenhouse gases in the atmosphere poses serious and diverse threats to life on earth. As scientists work to develop accurate models to predict the future impact of global earth warming, researchers, policy makers, and industry leaders are coming to terms with what can be done today to halt and reverse the human contributions to global climate change impact.

In the “business as usual” emissions scenario, climate change will have an array of substantial impacts on our society and the environment by the end of this century. Patterns of rainfall and drought are projected to shift in such a way that some regions currently stressed for water resources, such as the desert southwest of the United States and the Middle East, are likely to become drier. More intense rainfall events in other regions, such as Europe and the mid-western United States, could lead to increased flooding. Heat waves like the one in Europe in summer 2003, which killed more than thirty thousand people, are projected to become far more common. Atlantic hurricanes are likely to reach greater intensities, potentially doing far more damage to coastal infrastructure.

Furthermore, regions such as the Arctic are expected to warm faster than the rest of the globe. Disappearing Arctic sea ice already threatens wildlife, including polar bears and walruses. Given another 2°C warming (3.6°F), a substantial portion of the Greenland ice sheet is likely to melt. This event, combined with other factors, could lead to more than 1 meter (about 3 feet) of sea-level rise by the end of the century. Such a rise in sea level would threaten many American East Coast and Gulf Coast cities, as well as low-lying coastal regions and islands around the world. Food production in tropical regions, already insufficient to meet the needs of some populations, will probably decrease with future greenhouse global warming. Thee incidence of infectious disease is expected to increase in higher elevations and in latitudes with long term warming temperatures. In short, the impacts of future climate change are likely to have a devastating impact on society and our environment in the absence of intervention.