GLOBAL WARMING

Cannibalism amongst polar bears is rising

G. S. Mudur

In a sea-ice region of the Arctic Ocean, scientists have observed polar bears stalking, killing and eating other polar bears. Many species of plants across the middle and higher latitudes of the northern hemisphere are now flowering earlier than a few years ago. Migratory birds in Europe, Asia and Australia are arriving early. And the population of Emperor Penguins in parts of Antarctica has dropped by half over the past 50 years.
   The signs of climate change are burgeoning. Now, research by an international team of scientists has shown that 90 per cent of a large set of myriad changes in plants, animals, and other terrestrial systems believed to be linked to climate change are very close to predictions of human-induced global warming. The study has shown that the changes over the past 30 years are unlikely to have been caused by natural variations in climate.
   "We're now seeing the fingerprints of human-induced climate change on all the continents and in most of the oceans,' says Annette Menzel, head of the ecoclimatology division at the Technical University of Munich, Germany, a member of the team. "The patterns of change we see closely match simulations of the impacts of global warming."
   Recently published in Nature, Menzel and her colleagues from the National Aeronautics and Space Administration and other institutions analysed a number of changes observed since the 1970s on plants, animals and ecosystems. The study's significance lies in the use of statistical analysis to separate the impacts of human-induced warming from natural variations.
   "That was the real challenge' says David Karoly, of University of Melbourne. Weather data shows that the average surface temperature on Earth has risen by 0.7 degrees over the past century. The UN panel on climate change had asserted last year that this warming was "very likely" due to an increase in green-house gases mainly through fossil fuel burning. But there are some disbelievers - some diehard sceptics, but a few scientists, too.
   Richard Lindzen, a Harvard-trained atmospheric physicist at the Massachusetts Institute of Technology is among researchers who have argued that a significant part of the changes in surface temperatures observed worldwide over the past few decades may also reflect some natural variability.
   The new study led by Cynthia Rosenzweig at the NASA Goddard Institute for Space Studies, New York, might help demolish any such arguments. The new analysis shows that global warming is the top factor driving such changes - not deforestation or air pollution. "The data displaying patterns of change is strongest in North America, Asia and Europe mainly because far more studies have been done there:' says Rosenzweig.
   Biology appears to be bearing the brunt of the impacts. The researchers analysed data on about 800 terrestrial physical systems, but more than 28,000 plant and animal systems in which changes have been documented over the past three decades. The signs and impacts are seen around the world. In some parts of Canada, spring blooms now occur 26 days earlier and there is a decline in the body mass of Israeli passerine birds. The most ominous finding, of course, is evidence of rising mercury levels. Tree rings - which are peepholes into past climates - in Mongolia have shown that the temperatures are the warmest in the past 1,000 years. And it's only getting warmer, much faster than you'd imagine.
   Courtesy: Businessworld

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US residents consume five times more energy than world average

P. Hari in San Francisco

Suppose you are a staunch environmentalist. You live an austere, almost ascetic life, doing little that could harm the environment. You rarely travel, eat a vegetarian diet, and generate your own electricity from the sun. You think that your contribution of carbon emissions to the environment would be next to nothing. That is not true, say scientists at the Massachusetts Institute of Technology (MIT) in the US. Your contribution of emissions depends on where you live. No one has done this audit for Indian residents, but the results seem grim for those who live in the US. Even if you do nothing, you would still contribute twice as much as the world average.
   When MIT professor Timothy Gutowski and his students tried to calculate the carbon footprint of US lifestyles, their primary aim was to go away from national statistics and focus on individual lifestyles. A profligate lifestyle, no doubt, contributes enormously to carbon emissions, but statistics such as total or per capita emissions do not answer an important question. Would living an austere life reduce one's burden of emissions? The public thinks that it does, leading to several misconceptions about lifestyle. "A lot of people in America still want to be cowboys," says Gutowski. Now his study shows that even cowboys in America would emit far more carbon than people in other countries.
   The MIT team looked at people with 18 different lifestyles: that of Buddhist monks, senators, vegetarians, management consultants, corporate CEOs, five-year-old children, retired people and ultra-rich people such as Bill Gates. His students interviewed people with these lifestyles. They looked at variations in income within a lifestyle, and also variations of lifestyle within a fixed income. They also included something for the first time in such studies: the overhead for living in the US. The government provides subsidies worth $4,391 through services, and this becomes an overhead that creates emissions that have to be shared by everybody.
   The MIT team took 1997 as their base year, but the amount of carbon emitted per person now is almost the same as in 1997. They found that the minimum energy that a person in the US consumes is 120 giga joules. It is one-third the US average, but twice the world average. Large-income people consumed big amounts of energy and had a big impact on the environment. Bill Gates, for example, had a global warming potential 10,000 times the US average.
   It may be easy for Bill Gates to bring down his energy consumption. This was generally true of those in the high-income brackets. "An average US Senator maintained at least two large houses, and possibly another vacation home as well," says Christopher Cleaver, an MIT student. However, reducing energy use is not easy for the average American. For those in the middle-income bracket - $30,000 a year - energy use could be cut down by about 30 per cent. To cut the energy use by 50 per cent, they have to make lifestyle changes that would be unacceptable to most people. "There are limits to voluntary actions to reduce impacts," says Gutowski.
   What does it mean for other nations? The more developed the nation is, the higher is the likely subsidy, and the lesser is the scope for individuals to reduce the total emissions below a certain level. Many people interviewed for the MIT study were reluctant to make lifestyle changes. "People make lifestyle changes only when the price is right," says R.K. Pachauri, chairman of the UN's Intergovernmental Panel for Climate Change. That means subsidies for public transport and taxes for private vehicles.
   Courtesy: Businessworld

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