Friday, July 27, 2012

Rise in Temperature and Carbon Dioxide Follow One Another Closely

New research from the Niels Bohr Institute at the University of Copenhagen has shown that the rise in temperature after the last ice age into the warmer intergrlacial period was followed closely by a rise in atmospheric carbon dioxide, contrary to previously held opinion.
The research was published in the journal Climate of the Past and showed that, unlike what previous thought had shown, the increase in the amount of CO2 in the atmosphere following the end of the last ice age, approximately 19,000 years ago, followed a lot closer to the rise in temperature.
“Our analyses of ice cores from the ice sheet in Antarctica shows that the concentration of CO2 in the atmosphere follows the rise in Antarctic temperatures very closely and is staggered by a few hundred years at most,” explains Sune Olander Rasmussen, Associate Professor and centre coordinator at the Centre for Ice and Climate at the Niels Bohr Institute at the University of Copenhagen.
The research was based on measurements of ice cores taken from five boreholes through the Antarctic ice sheet.
“The ice cores show a nearly synchronous relationship between the temperature in Antarctica and the atmospheric content of CO2, and this suggests that it is the processes in the deep-sea around Antarctica that play an important role in the CO2increase,” explains Sune Olander Rasmussen.
Rasmussen explained that one of the theories is that when Antarctica warms there will be stronger winds over the Southern Ocean, which will force more water up from the deep bottom layers of the ocean where there is a much higher concentration of carbon dioxide. As this happens, a larger percentage of carbon dioxide will be released into the atmosphere, linking temperature and CO2 together.
The collapse of the last ice age is linked to the change in solar radiation caused by variations in the Earth’s orbit around the sun, the Earth’s tilt, and the orientation of the Earth’s axis. These variations are called Milankowitch cycles and take place in cycles of approximately 100,000, 42,000, and 22,000 years. These are the cycles that cause the Earth’s climate to shift between long ice ages of approximately 100,000 years and warm interglacial periods, typically 10,000 – 15,000 years.
“What we are observing in the present day is the mankind has caused the CO2content in the atmosphere to rise as much in just 150 years as it rose over 8,000 years during the transition from the last ice age to the current interglacial period and that can bring the Earth’s climate out of balance,” explains Sune Olander Rasmussen adding “That is why it is even more important that we have a good grip on which processes caused the climate of the past to change, because the same processes may operate in addition to the anthropogenic changes we see today. In this way the climate of the past helps us to understand how the various parts of the climate systems interact and what we can expect in the future.”
Source: University of Copenhagen

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Friday, July 20, 2012

What Is the Glycemic Index and How Can it Help Me Lose Weight?

The glycemic index (GI) is a measurement developed by Dr. David J. Jenkins and his associates at the University of Toronto in 1981. They were researching diabetes, and how to reliably predict the effect of certain foods on the body's blood sugar and insulin levels. The glycemic index rates carbohydrate-rich foods on a scale of 1 to 100, pure glucose being the highest (100). A food's GI rating indicates how rapidly it is digested or absorbed by the body; the higher a food is on this scale, the faster your body will use it up.
Why the glycemic index is important
This is important information – not only for diabetics but also for those interested in losing weight – because foods high on the glycemic index scale tend to give you a "sugar rush." They cause insulin to be released into your bloodstream to process the sudden rise in blood sugar. Unfortunately, once the blood sugar levels have been normalized, your body then has a tendency to crave more food to boost them again, causing a kind of "yo-yo" approach to eating. Also, insulin is considered a "fat storage hormone" because it causes sugar to enter the body's cells more quickly, so that it can be converted to energy, but at the same time causes them to store the excess sugars as glycogen or body fat.
How does the GI relate to losing weight?
So the glycemic index can be quite useful when trying to lose weight, and a useful complement to other diets. Foods with high GI ratings – white bread, cakes, white rice, baked potatoes, jams, jellies, and many processed breakfast cereals – will trigger this "yo-yo" effect, and leave you craving more food very quickly. These foods also tend to be high in calories. Foods with a GI rating lower than 55 – fruits and vegetables, milk products, high-fiber grains and cereals, beans and lentils, sweet potatoes, and pasta – have the opposite effect. They take longer to be digested, leading to an increased feeling of satiety. Because these foods are less processed, and because of their high fiber or particle size, they take up more space in your stomach and leave you feeling more satiated and full. As a result, you are less likely to "binge eat."
Paying attention to the GI ratings of foods has been proven to be a useful adjunct to many famous diet plans. Studies have shown that people on low-GI diets tend to lose more weight and keep it off than those on high-GI diets. One of the most successful commercial diet programs, Nutrisystem®, is largely based on glycemic index research. Whatever the diet program you choose, paying attention to the GI index of the foods you eat can help you make wiser choices. A diet rich in protein (which does not cause the same glycemic response in the body) and low-GI foods is going to be more likely to succeed.
Other benefits of eating low-GI foods
In addition, eating foods that have low GI ratings can be beneficial to your health in many other ways. Low-GI diets have been proven to reduce blood fat levels. They also provide more sustained energy during the day, offering a steadier release of sugar into the bloodstream, instead of a "sugar rush." This sustained release of nutrients helps to keep both your blood sugar and your energy levels more stable, which provides a healthy stability to the system, as opposed to the "yo-yo" effect. Low glycemic index diets have been proven to increase athletic performance, and have been shown in studies to improve blood cholesterol levels and reduce heart disease and metabolic syndrome. Foods with a low GI rating are also rich in phytochemicals, which have known protective and disease-preventing properties. Naturally, remembering the original inspiration for Dr. Jenkins' research on the glycemic properties of foods, diets that are rich in low-GI foods can also help to lower the risk of type 2 diabetes, a disease that is sadly becoming epidemic these days.
How do I take advantage of the glycemic index ratings?
As with any diet, however, moderation is the key. Don't rush off and look up a list of foods with low GI ratings and eat only those foods. Combine them with the recommended amounts of meat, chicken, fish, or other proteins. But becoming more aware of the glycemic index and the ratings assigned to common foods can help with almost any healthy diet, if for no other reason than that low-GI foods tend to be more natural, less processed, and thus better for you.

Tuesday, July 17, 2012

Businesses clearly have a major role to play in any strategy for saving the planet. They are the engines of the developed economies that devour a disproportionate share of the world’s nonrenewable resources and produce a disproportionate share of its emissions. They also generate innovations that reduce resource use and lessen pollution. As both a cause of and a solution to environmental degradation, they are inevitably at the center of sustainability debates.
But how, exactly, can businesses contribute? According to one line of reasoning, rescuing the environment involves restraint and responsibility: Consumers and companies must do more with the resources they consume, recycle and process their waste more efficiently, and curb their appetite for consumption. In short, resources are finite and need to be carefully husbanded—an argument that appeals directly to the traditional virtue of moderation. This worldview achieved perhaps its clearest expression in the works of the 19th-century economist Thomas Malthus, who feared that at prevailing population growth rates the planet would eventually be unable to feed itself.
Although the Malthusian view exercises a powerful influence on voters and politicians alike, it is by no means uncontested. Another line of reasoning, which flows from the work of the 20th-century economist and Nobel Prize winner Robert Solow, is that environmental and other problems can always be resolved through the exercise of human ingenuity. This view appeals to our natural optimism and underlies much advocacy for deregulation and the promotion of growth.
It’s not hard to see why these two philosophies make uneasy bedfellows. Yet if we are to achieve real progress in solving the world’s environmental problems, we will have to apply both of them.
The World According to Malthus In the original Malthusian argument, if the world’s population grows faster than the planet’s ability to produce food and other necessities, the cost of those necessities will rise while wages fall because more people will be available to work. At a certain point we will no longer be able to afford children and as a result will stop having them, leading to a sudden population collapse.
When he laid out this apocalyptic theory 200 years ago, Malthus was the center of intellectual attention. His dire view provoked strong arguments in support and in opposition. Among other things, it helped shape the Corn Laws, British tariffs designed to limit the availability of cheap foreign imports. Malthus was known to be one of Charles Darwin’s many sources of inspiration.
But Malthus wrote at a time before agricultural mechanization, when 90% of Americans, for example, worked on farms. The linear growth in agricultural production that was central to his thesis turned dramatically geometric as the Americas, New Zealand, and Australia opened up to farming and then mechanized. Staggering productivity growth in manufacturing as well as agriculture followed. Malthus seemed to have entirely missed the mark, while Alfred Marshall, the dominant British economist of his time, explained to the world that productivity growth was now a centrally important feature of economic performance, spurring generations of economists to study it.
Malthus’s ideas reentered the mainstream for a brief period 40 years ago, when Paul Erlich (The Population Bomb, 1968), the Club of Rome (The Limits to Growth, 1972), and William D. Nordhaus and James Tobin (Is Growth Obsolete?, 1972) all warned in vivid and uncompromising terms that conventional economic growth was on the verge of ruining the world. Once again events suggested that the warnings were misplaced: Energy and commodity prices fell, deregulation delivered the benefits of more-intense competition, and the technology revolution boosted opportunities and productivity. Today, however, as apprehension about environmental degradation mounts, Malthus’s notion that we are headed inexorably toward our own destruction is back at the center of the public discourse, heating up the debate about the role of corporations in finding solutions to urgent global problems.
Modern Malthusianism generalizes the argument beyond food: The better we get at making things, the cheaper it is to consume and the faster we reproduce and use up the planet’s resources. The fear is that economic growth comes at the expense of the world’s natural resources, including oil, fish, clean air, clean water, carbon-absorbing forests, and so on. Our economic activity not only eats up nonrenewable resources but degrades the ecosystem while fueling faster and faster population growth. In other words, we are steadily approaching a metaphorical wall that lurks out there in the distance. Each year we get closer and closer; eventually we will smack into the wall, with devastating consequences that include natural disaster, plague, famine, and death. The only possible recourse is to slow our progress.