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…)

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…)

The product gas can be burned in boilers to generate heat and raise steam, in internal combustion engines to generate electricity and heat at small to medium scale (from a few kilowatts to a few megawatts), and in gas turbines to generate electricity (Brayton cycle) and heat at small to large scale. In large-scale systems using gas turbines, the exhaust gas from the gas turbine can be used to raise steam in a heat recovery steam generator to generate additional electricity using a steam turbine (Rankine cycle), resulting in combined cycle operation. (more…)

Options for dealing with the threats of climate change include both adaptation to inevitable changes and mitigation, or lessening, of those changes that we can still affect. One possible adaptation would be to adjust our agricultural practices to the changing regional patterns of temperature and rainfall. Another would be to build coastal defenses against the inundation from sea-level rise. Only mitigation, however, can prevent the most threatening changes. (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.

Transport applications tend to demand rapid start-up and instant dynamic response from fuel cell systems, so a high-temperature fuel cell is unlikely to be competitive as the main engine in applications such as cars and buses. The prime candidate for these vehicle propulsion systems is the Polymer Electrolyte Fuel Cells, which exhibits both of the above characteristics while also having very high power density. This is important as it must also occupy a similar amount of space to an internal combustion engine. Of recent interest has been the development of auxiliary power units for vehicles, in which the fuel cell meets the onboard electric load of the vehicle. Both Polymer Electrolyte Fuel Cells and ITSOFCs are under development for this application. (more…)

Nuclear energy has some distinct advantages in strengthening the external dimension of energy supply security. These include:

• Nuclear power plants produce electricity domestically. Their capital and labor inputs are also provided domestically. With more than 90% of its inputs in terms of value sourced domestically, it can be considered a largely domestic source of energy and electricity.

• Of course, a majority of OECD countries import part or all of their requirements of uranium plutonium. (more…)

Energy is consumed by various segments of the economy, including households, commercial establishments, manufacturing enterprises, and electric power generators. Only a portion of total energy demand is sensitive to temperature changes. (more…)

Although the focus of many policy studies of climate change is on establishing the causal links between anthropogenic systems, emissions of greenhouse gases climate change, the line of causation also runs the other way. Short-term fluctuations in climate conditions, particularly in the temperate zones on the planet, affect energy consumption. If the popular expectation that the climate will become warmer becomes a reality, we can expect winters and summers that are warmer than those of the past. (more…)

Establishing the impact of climate change on energy demand requires a measure of heating and cooling requirements. In the United States, this measure is a degree day, which is defined in terms of an absolute difference between average daily temperature and 651F, which is an arbitrary benchmark for household comfort. Commercial heating degree days are incurred when outside temperatures are below 651F, generally during the winter heating season from October through March. (more…)