Tuesday, October 21, 2014

Earth’s magnetic field ‘could flip in the space of 100 years’, scientists warn

[Metro] Scientists predict that the Earth’s magnetic field can flip far faster than previously thought – unleashing a force which Mayan apocalypse believers thought might destroy our planet in 2012.
Berkeley scientists say that the Earth’s magnetic field can weaken and dip within just 100 years, before flipping so that compasses point south – an event they admit could wreck the entire world’s power grid and expose the world to deadly cosmic rays.
Earth’s magnetic field is weakening 10 times faster than normal at present, leading geophysicists to predict a flip within a few thousand years – but Discovery news says that could understimate the speed of the change.
Authors such as Robert Felix claim that previous reversals have been associated with mass disruptions such as the extinction of Neanderthal man, and with supervolcano eruptions and other apocalyptic events.
The ‘flip’ occurs regularly, but there has not been a documented instance for 800,000 years.
The Berkeley researchers say that apocalyptic events such as supervolcano eruptions are not likely – but that the flip could leave Earth exposed to cosmic rays which our magnetic field normally shields us from, leading to mutations and cancer in human beings.
Study co-author Paul Renne said, ‘We should be thinking more about what the biologic effects would be.’ Read More

Monday, October 20, 2014

The Next Green Revolution

". . . breakdown of food systems is the biggest threat of Climate Change."

[National Geographic] Something is killing Ramadhani Juma’s cassava crop. “Maybe it’s too much water,” he says, fingering clusters of withered yellow leaves on a six-foot-high plant. “Or too much sun.” Juma works a small plot, barely more than an acre, near the town of Bagamoyo, on the Indian Ocean about 40 miles north of Dar es Salaam, Tanzania. On a rainy March morning, trailed by two of his four young sons, he’s talking with a technician from the big city, 28-year-old Deogratius Mark of the Mikocheni Agricultural Research Institute. Mark tells Juma his problem is neither sun nor rain. The real cassava killers, far too small to see, are viruses.
Mark breaks off some wet leaves; a few whiteflies dart away. The pinhead-size flies, he explains, transmit two viruses. One ravages cassava leaves, and a second, called brown streak virus, destroys the starchy, edible root—a catastrophe that usually isn’t discovered until harvest time. Juma is typical of the farmers Mark meets—most have never heard of the viral diseases. “Can you imagine how he’ll feel if I tell him he has to uproot all these plants?” Mark says quietly.
Juma is wearing torn blue shorts and a faded green T-shirt with “Would you like to buy a vowel?” printed on the front. He listens carefully to Mark’s diagnosis. Then he unshoulders his heavy hoe and starts digging. His oldest son, who is ten, nibbles a cassava leaf. Uncovering a cassava root, Juma splits it open with one swing of his hoe. He sighs—the creamy white flesh is streaked with brown, rotting starch.
To save enough of the crop to sell and to feed his family, Juma will have to harvest a month early. I ask how important cassava is to him.
“Mihogo ni kila kitu,” he replies in Swahili. “Cassava is everything.”
Most Tanzanians are subsistence farmers. In Africa small family farms grow more than 90 percent of all crops, and cassava is a staple for more than 250 million people. It grows even in marginal soils, and it tolerates heat waves and droughts. It would be the perfect crop for 21st-century Africa—were it not for the whitefly, whose range is expanding as the climate warms. The same viruses that have invaded Juma’s field have already spread throughout East Africa.
Before leaving Bagamoyo, we meet one of Juma’s neighbors, Shija Kagembe. His cassava fields have fared no better. He listens silently as Mark tells him what the viruses have done. “How can you help us?” he asks.

Answering that question will be one of the greatest challenges of this century. Climate change and population growth will make life increasingly precarious for Juma, Kagembe, and other small farmers in the developing world—and for the people they feed. For most of the 20th century humanity managed to stay ahead in the Malthusian race between population growth and food supply. Will we be able to maintain that lead in the 21st century, or will a global catastrophe beset us?
The United Nations forecasts that by 2050 the world’s population will grow by more than two billion people. Half will be born in sub-Saharan Africa, and another 30 percent in South and Southeast Asia. Those regions are also where the effects of climate change—drought, heat waves, extreme weather generally—are expected to hit hardest. Last March the Intergovernmental Panel on Climate Change warned that the world’s food supply is already jeopardized. “In the last 20 years, particularly for rice, wheat, and corn, there has been a slowdown in the growth rate of crop yields,” says Michael Oppenheimer, a climate scientist at Princeton and one of the authors of the IPCC report. “In some areas yields have stopped growing entirely. My personal view is that the breakdown of food systems is the biggest threat of climate change.” Read More

Is California's drought worse than the Dust Bowl?

The atmospheric conditions that led to the so-called Dirty Thirties eight decades ago are present today, say researchers.

[CS Monitor] The catastrophic 1934 drought is one of the worst North America droughts on record, and was caused, in part, by an atmospheric condition that may have led to the current drought in California, a new study finds.
The 1934 drought affected about seven times more land area than other large droughts that hit North America between the years 1000 and 2005, and was almost 30 percent worse than the 1580 drought, the second most severe drought to hit the continent in the past 1,005 years.
"We noticed that 1934 really stuck out as not only the worst drought, but far outside the normal range of what we see in the record," lead researcher Ben Cook said in a statement. Cook is a climate scientist at NASA's Goddard Institute for Space Studies in New York City and holds a joint appointment at Columbia University's Lamont-Doherty Earth Observatory.
The same atmospheric phenomenon that emerged during the winter of 1933 to 1934 is also present today. This high-pressure ridge over the West Coast deflects storms holding much-needed rain, and may be causing the current drought crippling California, the researchers said.
"When you have a high-pressure system there, it steers storms much farther north than they would normally be," Cook told Live Science. "With this high pressure sitting there in the winter of 1933 to 1934, it blocked a lot of the rainfall and storms that you would expect to come into California."
It's unclear what causes the atmospheric ridge, however. "There's some evidence that maybe it could be forced by changes in ocean temperatures in parts of the Pacific, but by all accounts, it appears to be just a natural mode of variability in the atmosphere," Cook said.
This ridging pattern has been in place during some of the worst droughts to hit the West Coast, including the 1976 California drought, one of the worst dry spells in the state's history. California's current three-year drought is projected to cost the state $2.2 billion in 2014, and is predicted to continue in 2015, according to a July report from the University of California, Davis. Read More