Climate News
The Climate Killers
Meet the 17 polluters and deniers who are derailing efforts to curb global warming
The Profiteer: Warren Buffett, CEO, Berkshire Hathaway
Despite being a key adviser to Obama during the financial crisis, America's best-known investor has been blasting the president's push to curb global warming - using the same lying points promoted by far-right Republicans. The climate bill passed by the House, Buffett insists, is a "huge tax - and there's no sense calling it anything else." What's more, he says, the measure would mean "very poor people are going to pay a lot more money for their electricity." Never mind that the climate bill, according to the nonpartisan Congressional Budget Office, would actually save Americans with the lowest incomes about $40 a year.
The Disinformer: Rupert Murdoch, CEO, News Corporation
In 2007, when the world's most powerful media baron announced his newfound conviction that global warming "poses clear, catastrophic threats," it seemed as though the truth about climate change might finally get the attention it deserves. Murdoch promised that not only would News Corp. itself become carbon-neutral by 2010, but that his media outlets would explain the urgent need for a cap on carbon emissions. Climate change, he pledged, would be addressed as a sober reality across the News Corp. empire, whether as a plot element on 24 or in a story on Fox News. "I don't think there's any question of my conviction on this issue," Murdoch declared. "I've come to feel it very strongly."
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Glaciers: Changing at a Less Than Glacial Pace
Glaciers are thought to change at, well, a glacial pace. Certainly that has been true throughout the planet's history. The current ice age - known as the Pilocene-Quatenary glaciation, which began 2.6 million years ago - has witnessed some 20 cycles of glacial (freezing) and interglacial (thawing) periods, with ice sheets advancing and retreating completely on roughly 100,000-year time scales. But scientists are unsure exactly what prompts the shifts in cycles.
In glacial periods, vast ice sheets cover much of the planet, and sea levels are as much as 130 meters lower than they are today (all that extra water is locked up in ice). During interglacial periods - we are enjoying one now, East Coast blizzards notwithstanding - the ice sheets retreat, the glaciers melt and sea level rises. The expansive but quickly melting ice sheets of Greenland, the North Pole and Antarctica are all that is left of our last glacial period, which reached its peak about 20,000 years ago.
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Mammoth iceberg could alter ocean circulation: study
PARIS (AFP) - An iceberg the size of Luxembourg knocked loose from the Antarctic continent earlier this month could disrupt the ocean currents driving weather patterns around the globe, researchers said Thursday.
While the impact would not be felt for decades or longer, a slowdown in the production of colder, dense water could result in less temperate winters in the north Atlantic, they said.
The 2550 square-kilometre (985 square-mile) block broke off on February 12 or 13 from the Mertz Glacier Tongue, a 160-kilometer spit of floating ice protruding into the Southern Ocean from East Antarctica due south of Melbourne, researchers said.
Some 400 metres (1300 feet) thick, the iceberg could fill Sydney Harbour more than 100 times over.
It could also disturb the area's exceptionally rich biodiversity, including a major colony of emperor penguins near Dumont d'Urville, site of a French scientific station, according to the scientists.
"The ice tongue was almost broken already. It was hanging like a loose tooth," said Benoit Legresy, a French glaciologist who has been monitoring the Metz Glacier via satellite images and on the ground for a decade in cooperation with Australian scientists.
The billion-tonne mass was dislodged by another, older iceberg, known as B9B, which split off in 1987.
Jammed against the Antarctic continent for more than 20 years, B9B smashed into the Metz tongue like a slow-motion battering ram after it began to drift.
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Get This: Warming Planet Can Mean More Snow
With snow blanketing much of the country, the topic of global warming has become the butt of jokes.
Climate skeptics built an igloo in Washington, D.C., during the recent storm and dedicated it to former Vice President Al Gore, who's become the public face of climate change. There was also a YouTube video called "12 inches of global warming" that showed snow plows driving through a blizzard.
For scientists who study the climate, it's all a bit much. They're trying to dig out.
Most don't see a contradiction between a warming world and lots of snow. That includes Kevin Trenberth, a prominent climate scientist at the National Center for Atmospheric Research in Colorado.
"The fact that the oceans are warmer now than they were, say, 30 years ago means there's about on average 4 percent more water vapor lurking around over the oceans than there was, say, in the 1970s," he says.
Warmer water means more water vapor rises up into the air, and what goes up must come down.
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SNOW NO MORE!
For the second time in less than a week the Mid-Atlantic region of the US has been hit by a blizzard. This you may have already heard. The storm of February 9 -10 deposited 10 - 20 inches of snow from Virginia to New York. Nearby, at the Baltimore airport, about a foot was measured, bringing the season total to more than six feet. The normal average yearly snowfall is about 18 inches there.
There's another snow event on the way for President's Day, February 15.
It's true that no single storm, not even the storms of one season, can be blamed on global warming and a changing climate. Only weather patterns over a decade or so should be looked at to determine climate trends.
However, these things we know:
--- Since the beginning of industrial times man has been changing the composition of the atmosphere. The air we breathe today in the onion-skin-thin atmosphere is not the same as the air of over 150 years ago. Some pollutants fall out of the sky within days, but carbon dioxide lingers.
--- It takes warm moist air, mixed with microscopic solid particles and cold air to make precipitation - snow and rain. It is the chance combination of these ingredients in the atmospheric soup, stirred up by an area of low pressure, that will create a snow or rain storm. Storms are continually fed with these ingredients as they travel along.
--- A snowstorm needs warm moist air to flourish. The more humidity the better. The average annual snowfall at the South Pole is about an inch. (It just doesn't melt.) Snow is a warm, moist air event, not one made by cold dry air.
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Study: Can Hurricanes Cause Climate Change?
Back in the Pliocene era, between 5 million and 3 million years ago, the average global temperature was about 7oF warmer than it is today, yet atmospheric carbon dioxide levels were about the same. If carbon dioxide were the sole factor in warming, that wouldn't make any sense. It isn't, of course; there are several other contributors, including the brightness of the sun and the location of the continents (whose positions dictate, among other things, where ice caps can form) - but these were all pretty much the same in the Pliocene as well.
So what accounted for the higher global temperature? According to a new paper in Nature, one possible factor is hurricanes. Scientists have long suspected that global warming could make hurricanes more intense somehow, but the new study suggests the effect works both ways: tropical cyclones could help drive up temperatures in response. "We're suggesting that hurricanes could have created a permanent El Niño condition," says Yale's Alexey Fedorov, lead author of the study.
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Study: Warming to bring stronger hurricanes
WASHINGTON - Top researchers now agree that the world is likely to get stronger but fewer hurricanes in the future because of global warming, seeming to settle a scientific debate on the subject.
But they say there's not enough evidence yet to tell whether that effect has already begun.
Since just before Hurricane Katrina hit Louisiana and Mississippi in 2005, dueling scientific papers have clashed about whether global warming is worsening hurricanes and will do so in the future. The new study seems to split the difference. A special World Meteorological Organization panel of 10 experts in both hurricanes and climate change - including leading scientists from both sides - came up with a consensus, which is published online Sunday in the journal Nature Geoscience.
"We've really come a long way in the last two years about our knowledge of the hurricane and climate issue," said study co-author Chris Landsea, a National Oceanic and Atmospheric Administration top hurricane researcher. The technical term for these storms are tropical cyclones; in the Atlantic they get called hurricanes, elsewhere typhoons.
The study offers projections for tropical cyclones worldwide by the end of this century, and some experts said the bad news outweighs the good. Overall strength of storms as measured in wind speed would rise by 2 to 11 percent, but there would be between 6 and 34 percent fewer storms in number. Essentially, there would be fewer weak and moderate storms and more of the big damaging ones, which also are projected to be stronger due to warming.
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Oceans' acidity rate is soaring, claims study
The rate at which the oceans are becoming more acidic is greater today than at any time in tens of millions of years, according to a new study.
Rapidly rising concentrations of carbon dioxide in the atmosphere mean that the rate of ocean acidification is the fastest since the age of the dinosaurs, which became extinct 65m years ago, scientists believe.
The oceans are likely to become so acidic in coming centuries that they will become uninhabitable for vast swathes of life, especially the little-studied organisms on the deep-sea floor which are a vital link in the marine food chain.
Scientists have concluded, in a study published today in the journal Nature Genetics, that the current rate of ocean acidification is up to 10 times faster than 55m years ago - the last time the deep oceans became so acidic.
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An Ominous Warning on the Effects of Ocean Acidification
A new study says the seas are acidifying ten times faster today than 55 million years ago when a mass extinction of marine species occurred. And, the study concludes, current changes in ocean chemistry due to the burning of fossil fuels may portend a new wave of die-offs.
The JOIDES Resolution looks like a bizarre hybrid of an oil rig and a cargo ship. It is, in fact, a research vessel that ocean scientists use to dig up sediment from the sea floor. In 2003, on a voyage to the southeastern Atlantic, scientists aboard the JOIDES Resolution brought up a particularly striking haul.
They had drilled down into sediment that had formed on the sea floor over the course of millions of years. The oldest sediment in the drill was white. It had been formed by the calcium carbonate shells of single-celled organisms - the same kind of material that makes up the White Cliffs of Dover. But when the scientists examined the sediment that had formed 55 million years ago, the color changed in a geological blink of an eye.
"In the middle of this white sediment, there's this big plug of red clay," says Andy Ridgwell, an earth scientist at the University of Bristol.
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Greenland ice loss driven by warming seas: study
PARIS - Greenland's continent-sized icesheet is being significantly eroded by winds and currents that drive warmer water into fjords, where it carves out the base of coastal glaciers, according to studies released Sunday.
The icy mass sitting atop Greenland holds enough water to boost global sea levels by seven metres (23 feet), potentially drowning low-lying coastal cities and deltas around the world.
At present, the ocean watermark is rising at around three millimetres (0.12 inches) per year, a figure that compares with 1.8mm (0.07 inches) annually in the early 1960s.
But Greenland's contribution has more than doubled in the past decade, and scientists suspect climate change is largely to blame, although exactly how this is occurring is fiercely debated.
Some theories point to air temperatures, which are rising faster in far northern latitudes than the global average.
A rival idea is that shifting currents and subtropical ocean waters moving north are eroding the foundation of coastal glaciers, accelerating their slide into the sea, especially those inside Greenland's many fjords.
Until now, however, these studies have been mainly based on mathematical models rather than observation.
A team of scientists led by Fiammetta Straneo of Woods Hole Oceanographic Institution in Massachusetts set out to help fill that data void.
Working off of a ship in July and September 2008, the researchers took detailed measurements of the water properties in the Sermilik Fjord connecting Helheim Glacier in eastern Greenland with the ocean.
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Permafrost rapidly deteriorating in northern Quebec: Study
The thawing and decay of telltale, reddish mounds along the eastern shore of James Bay have led a team of Quebec researchers to conclude that the region's permafrost line has moved rapidly northward - about 130 km in just 50 years - as part of a broader transformation of Canada's sub-Arctic frontier in the age of climate change.
And the University of Laval researchers are warning that "if the trend continues, permafrost in the region will completely disappear in the near future."
The study, carried out by biologists Simon Thibault and Serge Payette, is published in the scientific journal Permafrost and Periglacial Processes.
The researchers used red-tinged landforms called "palsas" - small, lichen-covered hills that form over frozen peat bogs - as an indicator of the state of the permafrost in an area along the southeast coast of James Bay.
Described as "easy to spot in the field," the palsas were observed by helicopter and compared with records from 1957 that showed the distinctive mounds were present in seven out of seven representative bogs between the 51st and 53rd parallels.
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Methane levels may see 'runaway' rise, scientists warn
A rapid acceleration may have begun in levels of a gas far more harmful than CO2
Atmospheric levels of methane, the greenhouse gas which is much more powerful than carbon dioxide, have risen significantly for the last three years running, scientists will disclose today - leading to fears that a major global-warming "feedback" is beginning to kick in.
For some time there has been concern that the vast amounts of methane, or "natural gas", locked up in the frozen tundra of the Arctic could be released as the permafrost is melted by global warming. This would give a huge further impetus to climate
change, an effect sometimes referred to as "the methane time bomb".
This is because methane (CH4) is even more effective at retaining the Sun's heat in the atmosphere than CO2, the main focus of international climate concern for the last two decades. Over a relatively short period, such as 20 years, CH4 has a global warming potential more than 60 times as powerful as CO2, although it decays more quickly.
Now comes the first news that levels of methane in the atmosphere, which began rising in 2007 when an unprecedented heatwave in the Arctic caused a record shrinking of the sea ice, have continued to rise significantly through 2008 and 2009.
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A Farewell to Ice
Sea ice cover in the Arctic Ocean grew by an average of 13,000 square miles a day last month.
Great news, right? Well, not so much.
For one thing, it was January. Mid-winter. Sea ice cover is supposed to grow. For another, it ain't growing like it used to. In the 1980s, the average rate of ice growth was 35,000 square miles a day. According to the National Snow and Ice Data Center, average sea ice extent in the Arctic last month was 5.32 million square miles, which was 69,000 square miles above the record January low, set in 2006, but 417,000 square miles below the 1979-2000 average.
Now, nobody is predicting the disappearance of winter sea ice in the Arctic. Under even the most pessimistic of scenarios, the Arctic winter will be cold enough and dark enough that sea ice will continue to form, albeit at a reduced level. However, as NSIDC director Mark Serreze explained to Reuters, a reduction in winter sea ice extent - and the fact that the ice that remains is younger and thinner - sets up the Arctic for a summer "double whammy."
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The CO2 problem in 6 easy steps
For "an easy-to-understand explanation for why increasing CO2 is a significant problem," NASA scientist Gavin Schmidt has an excellent 2007 post.
The CO2 problem in 6 easy steps
We often get requests to provide an easy-to-understand explanation for why increasing CO2 is a significant problem without relying on climate models and we are generally happy to oblige. The explanation has a number of separate steps which tend to sometimes get confused and so we will try to break it down carefully.
Step 1: There is a natural greenhouse effect.
The fact that there is a natural greenhouse effect (that the atmosphere restricts the passage of long wave (LW) radiation from the Earth's surface to space) is easily deducible from i) the mean temperature of the surface (around 15ºC) and ii) knowing that the planet is roughly in radiative equilibrium.
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Can Climate Shift the Biology of Ecosystems?
Scientists have made lots of projections over the past few years about how warming temperatures and a changing climate will affect the planet. Real-world measurements have confirmed at least some of them: sea level is clearly rising, for instance, and the ice that covers the Arctic Ocean is shrinking and thinning - in the latter case, faster than anyone had expected just a few years ago.
Other measurements are a lot more difficult, though. It's reasonable to expect, for example, that ecosystems will change as plants and animals respond to a rising thermometer - but how do you measure the change of an ecosystem that may consist of hundreds or even thousands of species?
The answer, evident in a paper just published in the journal Global Change Biology, is that it isn't easy - but it's possible nevertheless. A team of scientists led by Stephen Thackeray, an expert on lake ecology at the United Kingdom's Centre for Ecology and Hydrology, has combed through observations of more than 700 species of fish, birds, mammals, insects, amphibians, plankton and a wide variety of plants across the U.K. taken between 1976 and 2005, and found a consistent trend: more than 80% of "biological events" - including flowering of plants, ovulation among mammals and migration of birds - are coming earlier today than they were in the 1970s.
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Hampton Roads in 'dire straits' because of global warming predictions, says expert
HAMPTON - Sobering evidence of how storms will have an increasingly devastating effect on the Peninsula as the century progresses is outlined in a new model by the Virginia Institute of Marine Science.
"This is an important issue for us to get moving on," Eric Walberg, physical and environmental planning administrator with the Hampton Roads Planning District Commission, told the Hampton City Council last week.
The hydrodynamic model produced by the Virginia Institute of Marine Science predicts the impacts of future storms. The effects of Hurricane Isabel, a Category 1 storm, in 2003 are replicated given predicted sea level rises over the century.
Much of eastern Hampton and Poquoson was flooded during Isabel. By 2085 much of the central Peninsula would be under water during an Isabel-type storm, according to the model.
Toward the end of the century, a Category 1 storm would have the same effect as a Category 2 storm does with today's sea level, he said.
"There's a couple of important take-home messages," Walberg said. "Over time moderate storm events like Isabel or the recent nor'easter will create flooding that's more severe.
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Science blogger finds errors in Met Office climate change records
A science blogger has uncovered a catalogue of errors in Met Office records that form a central part of the scientific evidence for global warming.
The mistakes, which led to the data from a large number of weather stations being discarded or misused, had been overlooked by professional scientists and were only discovered when the Met Office's Hadley Centre made data publicly available in December after the "climategate" e-mail row.
Although the errors do not alter the bigger picture on climate change, they have been seized upon as a further sign that scientific institutions have not been sufficiently transparent. "It makes you wonder how many other problems there are in the data," said John Graham-Cumming, the programmer who spotted the mistakes. "The whole idea of doing science without releasing your data is quite worrying."
Since being alerted of the problems last month the Met Office has issued a corrected version of its land-based temperature record on its website.
"We are grateful to Dr Graham- Cumming, but they are quite minor changes," said Peter Stott, head of climate monitoring and attribution at the Met Office. "It shows how open we are. We have put an exhaustive amount of information out there to show people exactly what we do."
The errors relate to the calculation of the average global temperature trend since 1850, based on measurements from land-based thermometers. The record is regarded as one of the most robust pieces of empirical evidence for global warming during the past century.
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India is Sinking into Earth's Mantle
Fun fact for you: scientists don't really know how the Himalayas formed. I mean yeah, they realize that the India tectonic plate is slamming into the Eurasia plate and has been for about 50 million years, but the mystery is why the mountain range is still growing. Usually when two continents collide it's like a car wreck -- there may be a bunch of mangled crust in the middle (mountains), but both vehicles stop moving.
Turns out, India appears to be sinking into the mantle. A new study based on computer models of the two plates shows that the formation and continued growth of the world's highest mountain range makes the most sense if a dense piece of India is down in the mantle, dragging the rest of the continent down with it.
That may not sound so weird but continents are buoyant; they're supposed to float, not sink. All the subduction you hear about all over the world is dense ocean crust sinking underneath continents. Except in the Himalayas. It's as though two cars collided, and one started to sink into the pavement.
This video gives you a rough outline of the old idea of how the Himalayas form. India's bending here, but it doesn't start heading it into the mantle on its own:
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Behind The Weather: Strongest El Nino In A Decade
Major snowstorms are set to bury the mid-Atlantic states this weekend after record snowfalls in December. Last month California was awash in rain. The Gulf states have seen heavy weather lately as well.
Turns out it's not just a run of bad luck. What's behind a lot of this winter's weather is El Nino, the tropical weather pattern that starts in the Pacific.
Scientists knew last summer that this was going to be an El Nino year. But it wasn't until the winter that its effects really hit the United States.
The strong El Nino and the subsequent precipitation are a result of something that started thousands of miles out in the Pacific Ocean.
"Ocean temperatures across the equatorial and tropical Pacific Ocean are somewhere upwards of two degrees above average," says Mike Halpert, deputy director of the Climate Prediction Center at the National Oceanic and Atmospheric Administration. "So we have had what we would characterize as a strong El Nino."
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Thirty-Eight Percent of World's Surface in Danger of Desertification
"Despite improvements in the LCA, it has a methodological weakness, which is a lack of environmental impact categories to measure the effect of human activities such as cultivation or grazing on the soil", Montserrat Núñez, lead author and a researcher at the Institute of Agro Food Research and Technology (IRTA), tells SINC.
The research, published in the latest issue of the International Journal of Life Cycle Assessment, is the first study in the world to include the impact of desertification in the LCA, based on classifying 15 natural areas or "eco-regions" according to their degree of aridity. By simultaneously using the LCA and a Geographic Information System (GIS), the researchers have shown that eight of these 15 areas can be classified as at risk of desertification, representing 38% of the land surface of the world.
The eight natural areas at risk are coastal areas, the Prairies, the Mediterranean region, the savannah, the temperate Steppes, the temperate deserts, tropical and subtropical Steppes, and the tropical and subtropical deserts.
"The greatest risk of desertification (7.6 out of 10 on a scale produced using various desertification indicators) is in the subtropical desert regions - North Africa, the countries of the Middle East, Australia, South West China and the western edge of South America", the scientist explains.
These are followed by areas such as the Mediterranean and the tropical and subtropical Steppes, both of which score 6.3 out of 10 on the scale of desertification risk. Coastal areas and the Prairies are at a lower risk of desertification, with 4 out of 10.
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Climate 'Tipping Points' May Arrive Without Warning, Says Top Forecaster
A new University of California, Davis, study by a top ecological forecaster says it is harder than experts thought to predict when sudden shifts in Earth's natural systems will occur -- a worrisome finding for scientists trying to identify the tipping points that could push climate change into an irreparable global disaster.
"Many scientists are looking for the warning signs that herald sudden changes in natural systems, in hopes of forestalling those changes, or improving our preparations for them," said UC Davis theoretical ecologist Alan Hastings. "Our new study found, unfortunately, that regime shifts with potentially large consequences can happen without warning - systems can ‘tip' precipitously.
"This means that some effects of global climate change on ecosystems can be seen only once the effects are dramatic. By that point returning the system to a desirable state will be difficult, if not impossible."
The current study focuses on models from ecology, but its findings may be applicable to other complex systems, especially ones involving human dynamics such as harvesting of fish stocks or financial markets.
Hastings, a professor in the UC Davis Department of Environmental Science and Policy, is one of the world's top experts in using mathematical models (sets of equations) to understand natural systems. His current studies range from researching the dynamics of salmon and cod populations to modeling plant and animal species' response to global climate change.
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'Fingerprinting' Method Reveals Fate of Mercury in Arctic Snow
ANN ARBOR, Mich.-A study by University of Michigan researchers offers new insight into what happens to mercury deposited onto Arctic snow from the atmosphere.
The work also provides a new approach to tracking mercury's movement through Arctic ecosystems.
Mercury is a naturally occurring element, but some 2000 tons of it enter the global environment each year from human-generated sources such as coal-burning power plants, incinerators and chlorine-producing plants.
"When released into the atmosphere in its reduced form, mercury is not very reactive. It can float around in the atmosphere as a gas for a year or more, and it's not really an environmental problem at the concentrations at which it occurs," said Joel Blum, the John D. MacArthur Professor of Geological Sciences.
But once mercury is oxidized, through a process that involves sunlight and often the element bromine, it becomes very reactive. Deposited onto land or into water, the mercury is picked up by microorganisms, which convert some of it to methylmercury, a highly toxic form that builds up in fish and the animals that eat them.
As bigger animals eat smaller ones, the methylmercury is concentrated. In wildlife, exposure to methylmercury can interfere with reproduction, growth, development and behavior and may even cause death. Effects on humans include damage to the central nervous system, heart and immune system. The developing brains of young and unborn children are especially vulnerable.
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Water levels at M'sian dams falling
KUALA LUMPUR: The prolonged oppressive hot weather experienced in some parts of the country has been partly attributed to climate change. A weather expert said climate change will see the country experiencing extreme weather conditions. These are expected to peak between 2025 and 2050.
During this period, the country may experience heavy showers and storms which could lead to flash floods. On the other extreme, hot spells may result in long droughts.
The heat wave over the past few weeks has affected many, especially padi farmers in Kedah. Households in some parts of Johor saw dry taps over the Chinese New Year holidays. Dams nationwide have also reported a drop in water levels.
All 42 meteorological stations nationwide reported temperatures above 30 degrees Celsius. The highest temperature reading was 36.7 degrees Celsius at Chuping, Perlis.
The highest temperature ever recorded in the country was 40.1 degrees Celsius, also at Chuping, on April 9, 1998.
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Region advances in environmental goals, deforestation and CO2 emissions keep rising
SANTIAGO, Chile -- Despite significant progress in some areas, the constant reduction of forest areas and the sustained increase of CO2 emissions in the region are impeding compliance with the seventh Millennium Development Goal (MDG7) on environmental sustainability, according to a report of United Nations organizations and agencies in Latin America and the Caribbean launched Wednesday in Mexico.
The study "Millennium Development Goals: Advances in Environmentally Sustainable Development in Latin America and the Caribbean" monitors the advances and difficulties in attaining the targets of the seventh MDG in the region.
These targets are: integrating the principles of sustainable development into country policies and programmes, reversing the loss of environmental resources, reducing biodiversity loss, increasing the population's sustainable access to safe drinking water and basic sanitation and significantly improving the lives of slum dwellers.
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Smoke bomb: The other climate culprits
IN JUNE 1783, lava and gases began pouring from the Laki fissure in Iceland in one of the biggest and most devastating eruptions in history. Poisonous gases and starvation killed a quarter of Iceland's population. The effects of the eight-month-long eruption were felt further afield, too. In the rest of Europe, a scorching summer of strange fogs was followed by a series of devastating winters. In North America, the winter of 1784 was so cold the Mississippi froze at New Orleans.
At the time, French naturalist Mourgue de Montredon suggested the eruption might be to blame, but two centuries passed before scientists started to work out how gas and dust from volcanoes affect climate. The main culprit is sulphur dioxide, which has a cooling effect. Laki pumped an estimated 120 million tonnes of the stuff into the atmosphere, cooling the northern hemisphere by as much as 0.3 °C over the next few years.
Nowadays, we are pumping out amounts of sulphur dioxide each year comparable to Laki's emissions. Human emissions rose rapidly over the 20th century, peaking at an estimated 70 million tonnes a year in the 1990s as developed countries cleaned up their act. Even such huge amounts, however, have not been enough to stop global warming: the cooling effect has been more than offset by the warming effect of carbon dioxide and other pollutants.
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