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Thread: Global warming - what will the effects be?

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    Site Caretaker Dave A's Avatar
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    Global warming - what will the effects be?

    As I was reading the article quoted below, I found myself wondering what the predicted changes were for my home city.

    Global warming will leave Sydney in permanent drought by 2070, with huge seas battering its famous beaches and raging bushfires threatening its outskirts, a report released on Wednesday says.

    The report from the national government's scientific agency predicts a grim future for Australia's largest and best-known city, concluding that climate change is inevitable and the city should start immediate planning.

    The CSIRO predicts the average Sydney temperature will rise 4,8 degrees Celsius, well above the average three degrees Celsius predicted globally by the United Nations Intergovernmental Panel on Climate Change.

    Rainfall is forecast to fall by 40% and the number of heat-related deaths in the city of four million is expected to soar almost 800% from the current 176 to 1 312 by 2050.

    The report said a 20cm rise in sea levels would result in storm surges of 22m on Sydney's beaches, leaving them eroded and inundating sea-side homes.

    The heat is expected to whip up 24% more wind storms and fuel almost double the number of severe bushfires in the state of New South Wales.
    full story from M&G here
    I seem to recall seeing a general forecast for South Africa that showed the North East getting wetter and the South West drier. But I wonder if there has been any region specific research to the extent shown in the Sydney report.
    The trouble with opportunity is it normally comes dressed up as work.

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    Silver Member Candy Bouwer's Avatar
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    I doubt it but would like to try and find out...this is something that really intrests me and should concern us all!!
    "NETWORKING" is a "CONTACT" sport!"
    Alcocks Electrical Entomological Hygiene

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    Site Caretaker Dave A's Avatar
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    The UN report has been released today.
    The United Nations climate panel issued its strongest warning yet on Friday that human activities are heating the planet, adding pressure on governments to do more to combat accelerating global warming.

    The Intergovernmental Panel on Climate Change (IPCC), the most authoritative group on warming grouping 2 500 scientists from more than 130 nations, predicted more severe rains, melting glaciers, droughts, heatwaves and rising sea levels.

    The final text said it was "very likely" -- or a probability of more than 90% -- that human activities led by burning fossil fuels explained most of the warming in the past 50 years.

    The IPCC report predicts a "best estimate" that temperatures would rise by between 1,8 and 4 degrees Celsius in the 21st century.

    Temperatures rose 0,7 degrees Celsius in the 20th century and the 10 hottest years since records began in the 1850s have been since 1994. The world is about 5 degrees Celsius warmer than during the last Ice Age.

    It also projects a rise in sea levels of between 18cm and 59cm in the 21st century -- and said that bigger gains could not be ruled out if ice sheets in Antarctica and Greenland thaw.
    full story from M&G here
    In a related story, it seems there is a concerted effort to undermine the report.
    Scientists and economists have been offered $10 000 each by a lobby group funded by one of the world's largest oil companies to undermine a major climate change report due to be published on Friday.

    Travel expenses and additional payments were also offered.

    Letters sent by the American Enterprise Institute (AEI), an ExxonMobil-funded think tank with close links to the Bush administration, offered the payments for articles that emphasise the shortcomings of a report from the United Nation's Intergovernmental Panel on Climate Change (IPCC).

    The AEI has received more than $1,6-million from ExxonMobil and more than 20 of its staff have worked as consultants to the Bush administration. Lee Raymond, a former head of ExxonMobil, is the vice-chairperson of AEI's board of trustees.

    The letters, sent to scientists in Britain, the United States and elsewhere, attack the UN's panel as "resistant to reasonable criticism and dissent and prone to summary conclusions that are poorly supported by the analytical work" and ask for essays that "thoughtfully explore the limitations of climate model outputs".

    Ben Stewart of Greenpeace said: "The AEI is more than just a think tank, it functions as the Bush administration's intellectual Cosa Nostra. They are White House surrogates in the last throes of their campaign of climate change denial. They lost on the science; they lost on the moral case for action. All they've got left is a suitcase full of cash."

    On Monday, another Exxon-funded organisation based in Canada will launch a review in London which casts doubt on the IPCC report. Among its authors are Tad Murty, a former scientist who believes human activity makes no contribution to global warming. Confirmed VIPs attending include Nigel Lawson and David Bellamy, who believes there is no link between burning fossil fuels and global warming.
    full story from M&G here
    The trouble with opportunity is it normally comes dressed up as work.

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    Ok this is going to be a long one so hold onto your seats:

    The most authoritative scientific report on climate change says with 90% certainty that the burning of fossil fuels and other human activities are driving climate change.

    The report, from the UN's Intergovernmental Panel on Climate Change, says the rise in global temperatures could be as high as 6.4°C by 2100. The report also predicts sea level rises and increases in hurricanes. Fewer cold days and nights and more hot ones are “virtually certain”, says the report.

    The new IPCC report is the work of 3750 climate experts, who have spent six years reviewing all the available climate research. It was released in Paris, France, on Friday.


    The last IPCC report (http://www.newscientist.com/article/...-warning.html), issued in 2001, predicted that temperatures would rise by 1.4°C to 5.8°C by 2100, relative to 1990 temperatures.



    But the new report says temperature rises by 2100 could, in the most extreme scenarios, range from 1.1°C and 6.4°C. The most likely range is 1.8°C to 4.0°C, with the report predicting that 4°C is most likely if the world continues to buy into a fossil-fuel intensive future (read the The impacts of rising global temperatures - http://environment.newscientist.com/...eratures.html).

    Melting, moving ice
    Rises in sea levels are predicted by the new report, threatening low-lying areas of land around the world. As the oceans warm, their waters expand, while rising temperatures also increase the melting of the ice sheets that cover Greenland and Antarctica.

    In 2001, the IPCC predicted that sea levels would rise by between 9 and 88 centimetres by 2100, relative to 1990 levels. The new report says rises could range from 18 cm to 59 cm. The top end of the range corresponds to a fossil-fuel intensive future ( see A1F1 scenario in Modelling the future climate: the baseline scenarios - http://environment.newscientist.com/...cenarios.html).

    But predictions of sea level rise will be one of the most contentious areas of the report - very recent research has suggested that rises of up to 140 cm are possible (see Shorelines may be in greater peril than thought - http://environment.newscientist.com/...n-thought.html. The understanding of how warming may affect the Greenland and Antarctic ice sheets remains limited, yet they are predicted to be the most important contributors to change.

    Climate change is also expected to affect the frequency and strength of tropical storms and hurricanes. The latest IPCC report says the activity of tropical cyclones is “likely” to increase over the 21st century. It says “likely” indicates a probability of more than 66%. This is a bolder statement than the World Meteorology Organisation issued in January.
    http://environment.newscientist.com/...-unproven.html

    Humans to blame

    Considering the human role in causing climate change, the IPCC report is damning: "The understanding of [human] influences on climate has improved since the [2001] report, leading to a very high confidence that human activities" are responsible for most of the warming seen since 1950, says the report’s summary for policymakers. “Very high confidence” is described as “at least a 9 out of 10 chance of being correct”.

    Before the industrial revolution, human greenhouse gas emissions were small, and the atmospheric concentration of carbon dioxide – the main greenhouse gas – was about 280 parts per million (ppm).

    Thanks largely to the burning of fossil fuels and changes in land use, such as agricultural exploitation and deforestation, the atmospheric concentration of carbon dioxide reached 379 ppm in 2005, says the IPCC.

    Gold standard
    The IPCC draws together the world's leading climate experts to review and assess all available research, under the auspices of UN Environment Programme and the World Meteorology Organization.

    The result of their assessment, which is done every five to six years, establishes what is considered the gold standard of consensus on climate change science.

    The latest IPCC report was written by hundreds of experts and reviewed by hundreds more, from 113 countries. It is being released in stages during 2007. The first chapter, released on Friday, deals with the scientific basis for climate change.

    The next two parts of the IPCC's 2007 assessment, plus a synthesis, will be released throughout the year. Part 2, dealing with the impacts of climate change and our vulnerability to those impacts, will be released in April. Part 3, to be released in May, deals with how we might mitigate these impacts.


    http://environment.newscientist.com/...humankind.html


    IPCC website
    http://www.ipcc.ch/


    -- posted by member of wellinformed.co.za

    The earth climate system is certainly one of the complex systems on our planet with the most severe impact on our lives. The complex interactions of the atmosphere with factors like the oceans, ice-shields, and of course human activity leads to and modifies self-organized, large-scale coherent patterns like hurricanes and the El Nino oscillation. Several articles in different journals discuss some of the recent findings into the complexity of climate dynamics. One of the most dramatic and erratic change patterns of terrestrial climate are the occurrence of ice ages in the northern hemisphere. There are a number of factors that can cause transitions between ice ages and inter-glacial periods. One of them could be the Arctic Oscillation (AO) an erratic (chaotic?) oscillation of atmospheric pressure systems over the North Pole. Another self-organized structure with significant importance especially for the climate in Northern Europe is the "North Atlantic" conveyor belt. It is primarily powered by cold seawater that is formed in the North Atlantic. It because it is more dense it sinks to the bottom of the ocean. The displaced water forms a deep ocean current going South. There it displaces warm tropical surface water that flows back up North (e.g. as the "Gulf Stream") and closes the circle. If for some reason the conveyor belt slows down it will cause a significant drop in temperature in the North and a raise in tropical sea-surface temperatures in the South. The resulting larger temperature difference in the atmosphere will in turn create wind and cloud patterns that can either weaken (negative feedback) or strengthen (positive feedback) of the weakened conveyor belt.

    The team of C. Ruehlemann et al. did a careful investigation into the history of past sea surface temperatures in the Northern Atlantic. They wanted to find out if climate changes happened uniformly over the Atlantic or if there was indeed a cooling in the North while there was a warming in the South. The first option they identified with greenhouse gases the second one with a breakdown of the conveyor belt. They could provide convincing evidence that indeed the conveyor belt action was a good indicator for climate change. Is this an argument against greenhouse gases as contributing factors for climate change? As the primary cause that makes the conveyor belt stop the authors mention fresh surface water in the North Atlantic. Since cold fresh water is not as heavy as cold salt water the surface water will not sink to the bottom of the ocean and the primary driving force has vanished.

    C. Ruehlemann et al. did not discuss where the fresh surface water was coming from. R.A. Kerr mentions that runoff from melting sea ice could be one large freshwater source. Sea ice has been melting at the alarming rate of 15% per decade. Arctic ice has lost 40% of its volume over the past 30 years. Instead of an average thickness of 3.1 meter arctic ice is currently down to about 1.6 meter. Changes in the temperature could have caused changes in storm tracks, therefore changes in cloud coverage and therefore changes in precipitation patterns. Which in turn will affect the sea ice runoff.

    K.Y.Vinnikov et al. have done large-scale computer simulations of the chaotic fluctuations of climate change over a period of 5000 years. They conclude from their results that the chance that the current sea ice meltdown is just a large natural swing that will correct itself after a while is 1:1000.

    Therefore it is predictable when at the current rate all arctic ice cover will be gone. The fourfold change in albedo from white ice to black water will induce a correspondingly increased heating of the surface water in Polar Regions. This will in turn reduce the mixing of surface and deep water, which means that the oceans will not act as CO2 and heat reservoir.

    All these complex feedback loops are classical ingredients of complex systems. The challenge will be to apply methods from complexity theory to attack the problem. Will control of chaos applied to geo-engineering help to get the conveyor belt jump-started again?


    -- something to consider that the world has been here alot longer then we have... it will just reset itself on us.

    --posted by me on wellinformed.co.za
    Wellinformed.co.za - Networking Forums SA partner site. Let's support each other for a better South Africa.

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