Think of the Sahara and you will conjure images of a vast desert landscape, with nothing but sand as far as the eye can see. But for a period of about 10,000 years, the Sahara was characterized by lush, green vegetation and a network of lakes, rivers and deltas. (more…)
Climate engineering won’t sufficiently stem global warming
orget about positioning giant mirrors in space to reduce the amount of sunlight being trapped in the earth’s atmosphere or seeding clouds to reduce the amount of light entering earth’s atmosphere. Those approaches to climate engineering aren’t likely to be effective or practical in slowing global warming. (more…)
If we had a second Earth, we could experiment with its atmosphere to see how increased levels of greenhouse gases would change it, without the risks that come with performing such an experiment. Since we don’t, scientists use global climate models.
In the virtual Earths of the models, interlocking mathematical equations take the place of our planet’s atmosphere, water, land and ice. Supercomputers do the math that keeps these virtual worlds turning — as many as 100 billion calculations for one modeled year in a typical experiment. Groups that project the future of our planet use input from about 30 such climate models, run by governments and organizations worldwide. (more…)
World’s mangroves, salt marshes hold potential for reducing carbon emissions
Mangroves, the dense forests found along tropical and subtropical coastlines, have some specialized trees that can take in air through their roots at low tide and excrete salt right out of their leaves. The unusual ecosystems can also absorb large amounts of carbon dioxide, making them a natural solution for controlling greenhouse gases.
Disrupt them, however, and they’ll put that carbon right back into the atmosphere. (more…)
ANN ARBOR — Mammal body size decreased significantly during at least two ancient global warming events. A new finding that suggests a similar outcome is possible in response to human-caused climate change, according to a University of Michigan paleontologist and his colleagues.
Researchers have known for years that mammals such as primates and the groups that include horses and deer became much smaller during a period of warming, called the Paleocene-Eocene Thermal Maximum (PETM), about 55 million years ago. (more…)
Temperatures in central China are 10 to 14 degrees Fahrenheit hotter today than they were 20,000 years ago, during the last ice age, UCLA researchers report — an increase two to four times greater than many scientists previously thought.
The findings, published on May 14, 2013, in the early online edition of the journal Proceedings of the National Academy of Sciences, could help researchers develop more accurate models of past climate change and better predict such changes in the future. (more…)
A new NASA and university analysis of ocean data collected more than 135 years ago by the crew of the HMS Challenger oceanographic expedition provides further confirmation that human activities have warmed our planet over the past century.
Researchers from the University of Tasmania, Sandy Bay, Australia; and NASA’s Jet Propulsion Laboratory, Pasadena, Calif., combined the ship’s measurements of ocean temperatures with modern observations from the international Argo array of ocean profiling floats. They used both as inputs to state-of-the-art climate models, to get a picture of how the world’s oceans have changed since the Challenger’s voyage. (more…)
Point Source Power’s cheap, rugged fuel cells can provide electricity where none exists.
In some parts of the developing world, people may live in homes without electricity or toilets or running water but yet they own cell phones. To charge those phones, they may have to walk for miles to reach a town charging station—and possibly even have to leave their phones overnight. Now a startup company spun off technology developed at Lawrence Berkeley National Laboratory (Berkeley Lab) has created a simple, inexpensive way to provide electricity to the 2.5 billion people in the world who don’t get it reliably.
Point Source Power’s innovative device is based on a solid oxide fuel cell that is powered by burning charcoal, wood or other types of biomass—even cow dung—the types of fuel that many in the developing world use for cooking. The fuel cell sits in the fire and is attached to circuitry in a handle that is charged as the fuel cell heats up to temperatures of 700 to 800 degrees Celsius. The handle, which contains an LED bulb, can then be detached and used for lighting or to charge a phone. (more…)
