Continuing on Global Warming from the last one.
This time I offer you couple of different views of Global Warming and it's effects.
- CO2 rise continues, but check out methane
- Life feels the effects of a changing climate
- Melting glaciers release toxic chemical cocktail
CO2 rise continues, but check out methane
This is a good reminder of what people are doing to the planet, but hardly news. For decades, every year has seen a new record high of CO2, as shown by the annual annoucements from the US National Oceanic and Atmospheric Administration. As Science reported in 2006:
"At no time in at least the past 10 million years has the atmospheric concentration of CO2 exceeded the present value"And judging from the data on the website of Yale's Mark Pagani, it looks like it has been about 20 million years since CO2 levels were as high as today's.
The gas just keeps building up.
What is new about the NOAA's greenhouse gas report this year is that methane levels also showed a clear increase for the first time in a decade.
Methane is a potent greenhouse gas, warming the planet 25 times more, molecule-for-molecule, than CO2. It doesn't last as long in the atmosphere, which tempers its kick, but it's still enough to give you nightmares. source
My comment: I like to point to the last paragraph above. You see that methane is really worst polluter than CO2 (which is to be expected, plants after all "eat" CO2). So you see, GW is making a chain reaction. The more time we waist in useless discussions, the more effects we will see. Most of them harming us, our economics or our life-style.
Life feels the effects of a changing climate
CLIMATE change is already altering our planet's biology, with only life in Antarctica so far spared its influence.
That's the conclusion from an analysis of tens of thousands of individual local studies covering shrinking glaciers, changing river flows, melting permafrost, increased coastal erosion, and warming lakes and rivers. It adds up, the authors say, to the first global picture that unambiguously demonstrates the effect of human-induced climate change.
The study, published in Nature (DOI: 10.1038/nature06937) this week, is based on more comprehensive data than any previous investigation of the biological effects of climate change. Cynthia Rosenzweig of NASA's Goddard Institute for Space Studies in New York, who led the project, says each continent shows the clear footprint of warming.
Her team examined 28,800 data sets that look for the impact of a changing climate on plants and animals, and found that 90 per cent of them revealed alterations "in the direction expected as a response to warming". The figure for physical changes such as diminishing glaciers was even higher, at 95 per cent. Included in Rosenzweig's study were climate change simulations generated using more than 3000 years of computer time.
The change that is having the biggest and most obvious biological impact is the early arrival of spring. This could cause entire ecosystems to become unbalanced if species respond to the warmer weather at different rates. These impacts were most concentrated, as might be expected, in Europe, North America and parts of Asia where there are already strong seasonal changes.
Worldwide, effects were also apparent in the ecosystems of oceans, lakes and rivers. Changes to the migration patterns of fish have led to them invading waters that were once too cold. Other important impacts include an increase in the extent of forest fires each year in Canada.
Rosenzweig's conclusion that the impacts are due to human-made change rather than natural climatic cycles is likely to prove controversial. Recent studies at the Walker Institute for Climate System Research at the University of Reading, UK, and the UK Met Office suggest that the strong warming seen in the north Atlantic and western Europe since 1975 may be due in large part to natural oscillations in ocean circulation, unconnected to human-made global warming. If so, many of the impacts Rosenzweig attributes to human-made climate change could be natural.
The controversy is unlikely to go away. A study in Nature this month (vol 453, p 84) led by Noel Keenlyside of the Leibniz Institute of Marine Sciences in Kiel, Germany, forecasts that this cyclical warming would soon abate. "There could be some cooling in Europe and North America over the coming decade as the natural cooling offsets the warming from human activities," Keenlyside says. source
Melting glaciers release toxic chemical cocktail
- 11:47 07 May 2008
The trace levels found will not harm the birds, but the presence of the chemical could be an indication that other frozen pollutants will be released because of climate change, says Heidi Geisz, a marine biologist at Virginia Institute of Marine Science in Gloucester in the US. She led a team that sampled DDT levels in the penguins.
She worries that glaciers could release an alphabet soup of chemical pollutants into the ocean, including PCBs and PBDEs – industrial chemicals that have been linked to health problems in humans.
Chemists first synthesised DDT (dichloro-diphenyl-trichloroethane) in 1874, but the chemical wasn't used an insecticide until the 1940s. DDT spraying slashed malaria rates in many countries, but the chemical's environmental toll was starting to cause concern.
The US banned most uses of the pesticide in 1972, and the UK followed suit in 1984. Some countries still use DDT to fight mosquito-borne diseases such as malaria and dengue, but worldwide usage has plummeted – from 40,000 tonnes per year in 1980 to 1,000 tonnes per year now.
DDT latches onto small airborne particles then migrates toward the poles. Geisz, who has worked in Antarctica since 1999, sought to gauge long-term changes in pollutants found in the continent's seabirds.
A 1964 survey found modest amounts of the pesticide in Adélie penguins, and Geisz's team expected to see even less four decades later. Instead, her team found DDT levels unchanged in birds that live near the continent's western peninsula.
As DDT crawls up the food chain, from plankton to krill to penguins, it breaks down into a sister molecule called DDE. The more DDE in an animal, the longer the chemical has been around, Geisz says. But her team recorded low levels of DDE in the birds, suggesting a fresh source.
Geisz couldn't figure out where the DDT came from until she looked back at glacial records. In the 1950s and 60s, Antarctic glaciers swelled, potentially locking in chemicals like DDT.
However, average winter temperatures on the Antarctic Peninsula have warmed 6 °C the past 30 years, and glaciers now melt faster than they grow. A recent study noted elevated levels of DDT in glacial runoff.
As the continent's western ice sheet melts, the DDT drips back into the ecosystem at a rate of 1 to 4 kg per year, her team estimates.
Derek Muir, a researcher at Environment Canada in Burlington, Ontario, says Arctic glaciers ought to store even more of the pesticide, but Arctic animals seem to be shedding the pesticide.
Even so, researchers ought to look more closely for evidence that melting glaciers are pumping chemicals like DDT into the Arctic, Muir says.
To make that case stronger for Antarctica, Geisz plans to track the flow of other pollutants from glaciers to birds.