Nature Features
Carbon dioxide and the greenhouse effect
May 4, 2007, 14:15 GMT
Hamburg - The so-called greenhouse effect of the earth's atmosphere is vital: a layer of air enveloping the planet lets about 70 per cent of incoming sun rays pass through, but retains a large part of the heat reflected by the Earth's surface.
This effect makes sure that the planet always has a comfortable median temperature of 15 degrees Celsius. Without the greenhouse effect we would be freezing at minus 18 degrees.
The greenhouse effect is caused by certain trace gases in the atmosphere that let short-wave radiation such as sunlight pass through easily, but hold back long-wave heat radiation.
Carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O, known as laughing gas) are among the main greenhouse gases after steam.
Since the beginning of industrialization, these gases, especially CO2, have been entering the atmosphere in large amounts through the burning of fossil fuels like coal, oil and gas.
Agriculture is another source of greenhouse gases.
With more intensive farming practices, deforestation, increasing numbers of cars on our roads, rising industrial production in developed countries and the industrialization of developing nations, the situation is getting worse by the day.
As humans produce more greenhouse gases, the atmosphere absorbs more heat, causing global warming and changing the Earth's climate.
Some visible effects of global warming are melting glaciers, rising sea levels, and worsening weather conditions such as heat waves and stronger storms.
CO2, methane and nitrous oxide make up nearly 90 per cent of man- made greenhouse gases, says the United Nations World Meteorological Organization (WMO). With the emission of those gases, humans increase the natural greenhouse effect.
Compared to measurements taken around 1750 - before industrialization - figures at the end of 2005 had increased as follows: carbon dioxide up 35.4 per cent, nitrous oxide up 18.2 per cent and methane up 154.7 per cent.
The average CO2 concentration in 2005 was 379.1 ppm (parts per million of air). The average for methane was 1.78 ppm, for nitrous oxide 0.32 ppm. At the beginning of industrialization, the CO2 concentration stood at 280 ppm. (internet: www.wmo.int)
© 2007 dpa - Deutsche Presse-AgenturCOMMENT
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Older Talkback
page: 1
You rat people that cant adapt, already made your stupid comments. Hard to imagine a story this bogus would make it. While we are at it, What is your take on the Ice age?
Just days before Gore's charge up Capitol Hill, a high profile climate debate between prominent scientists ended with global warming skeptics being voted the clear winner. Before the start of the debate, held in New York City, the audience polled 57.3% to 29.9% in favor of believing that Global Warming was a crisis.
But following the debate the numbers completely flipped to 46.2% to 42.2% in favor of the skeptical point of view. Conclusion - when people hear both sides they can easily judge for themselves what is truth.
Item: On March 13, The New York Times, one of the most adamant promoters of the Global Warming gospel, published a landmark article stating 'scientists argue that some of (former Vice President Al) Gore's central points are exaggerated and erroneous.'
Item: French scientist Claude Allegre, a prominent French Socialist and supporter of Global Warming dogma, recanted his belief in man-made catastrophic global warming and now says promotion of the idea is motivated by money.
Item: One of Israel's top young scientists, Nir Shaviv, recently reversed his opinion, declaring that the link between emissions and climate variability has nothing more that 'circumstantial evidence.'
Item: The United Kingdom's famed environmental activist David Bellamy also recently converted to skepticism, as did Meteorologist Reid Bryson, who has switched from the 1970's global cooling scare to a global warming skeptic.
Item: A report by the Heartland Institute, entitled 'What Climate Scientists Really Say About Global Warming,' exposes the weakness of the 'consensus' claims of Global Warming shock troops. To reach its findings the report examined two surveys conducted among climate scientists; the first in 1996, and the second in 2003. Both surveys confirm scientists are divided on the issue. Says the report -
-- More climate scientist 'strongly disagree' than 'strongly agree' with the notion that climate change is caused by humans.
-- Most climate scientists do not believe 'the current state of knowledge is able to provide reasonable predictions of climate variability' over 100-year periods.
-- Only 2 percent of climate scientists surveyed 'strongly agree' that modeling programs designed to predict climate changes are accurate, and
-- Almost all climate scientists agree that climate change could have 'positive effects for some societies.'
Item: After Global Warming propagandists rushed to declare that the UN's Intergovernmental Panel on Climate Change (IPCC) report proved conclusively that Global Warming was caused by human action, (a report by the way that won't be released until May) the just released summary predicts less global warming than was forecast by previous IPCC reports.
Item: New research by international scientists is revealing that the sun has been a major driver of climate variability. Solar specialist Henrik Svensmark of the Danish National Space Center explained 'We have the highest solar activity we have had in at least 1,000 years.'
As Senator James Inhofe (R-OK) sums it up, 'The usual suspects will still insist that there is a 'consensus' of scientists who agree with Gore. And yes, many governing boards and spokesmen of science institutions must toe the politically correct line of Gore-inspired science, but rank and file scientists are now openly rebelling.
As real debate finally forces fact over headline-making one liners, the truth will become ever more inconvenient to Al Gore and his Global Warming zealots.
More head in the sand stuff - so 'almost all scientists agree that warming will be beneficial for SOME societies' What about the others, driven out of their habit by drought? They'll be migrating to the remaining habitable countries - so expect a few million Mexicans coming across the border to the US (Mexico being one of the first to suffer drought) Or Florida being under the sea - that doesn't seem to be much of a benefit ?
You need to start thinking in World terms not narrow vision, American backyard stuff
Only 2% of scientists 'strongly agree' that modelling is accurate. What a pathetic attempt to try and make your case - what about the other 98% - are they 'strongly disagreeing ?' Of course not - like any questionaire (assuming it was unbiased and properly organised) there will be a range of possible choices. What is needed is the proportion overall agreeing or not agreeing. Picking out a very minor part to support your case is typical of the worst type of 'spin' and misinformation.
The sun's most obvious magnetic features are sunspots, formed as magnetic fields rip through the sun's surface. A magnetically active sun boosts the number of sunspots, indicating that vast amounts of energy are being released from deep within.
Typically, sunspots flare up and settle down in cycles of about 11 years. In the last 50 years, we haven't been living in typical times: 'If you look back into the sun's past, you find that we live in a period of abnormally high solar activity,' Dr. Weiss states.
These hyperactive periods do not last long, 'perhaps 50 to 100 years, then you get a crash,' says Dr. Weiss. 'It's a boom-bust system, and I would expect a crash soon.'
In addition to the 11-year cycle, sunspots almost entirely 'crash,' or die out, every 200 years or so as solar activity diminishes. When the crash occurs, the Earth can cool dramatically. Dr. Weiss knows because these phenomenon, known as 'Grand minima,' have recurred over the past 10,000 years, if not longer.
'The deeper the crash, the longer it will last,' Dr. Weiss explains. In the 17th century, sunspots almost completely disappeared for 70 years. That was the coldest interval of the Little Ice Age, when New York Harbour froze, allowing walkers to journey from Manhattan to Staten Island, and when Viking colonies abandoned Greenland, a once verdant land that became tundra. Also in the Little Ice Age, Finland lost one-third of its population, Iceland half.
The previous cooling period lasted 150 years while a minor crash at the beginning of the 19th century was accompanied by a cooling period that lasted only 30 years.
In contrast, when the sun is very active, such as the period we're now in, the Earth can warm dramatically. This was the case during the Medieval Warm Period, when the Vikings first colonized Greenland and when Britain was wine-growing country.
No one knows precisely when a crash will occur but some expect it soon, because the sun's polar field is now at its weakest since measurements began in the early 1950s. Some predict the crash within five years, and many speculate about its effect on global warming. A mild crash could be beneficial, in giving us Earthlings the decades needed to reverse our greenhouse gas producing ways. Others speculate that the recent global warming may be a blessing in disguise, big-time, by moderating the negative consequences of what might otherwise be a deep chill following a deep crash. During the Little Ice Age, scientists estimate, global temperatures on average may have dropped by less than 1 degree Celsius, showing the potential consequences of even an apparently small decline.
Dr. Weiss prefers not to speculate. He sees the coming crash as an opportunity to obtain the knowledge necessary to make informed decisions on climate change, and the extent to which man-made emissions have been a factor.
'Having a crash would certainly allow us to pin down the sun's true level of influence on the Earth's climate,' concludes Dr. Weiss. Then we will be able to act on fact, rather than from fear.
For more information on the Great Global Warming swindle, put 'Independent Global Warming Swindle' into Google
What about the fact that higher levels of carbon dioxide promote plant growth in the higher altitude alpine areas. Higher carbon dioxide is therefore good for holding the land together and preventing silt in the rivers. This is good for everybody.
If global warming is only an effect of the sun as some people who study planetary physics think, then the extra carbon dioxide might be the only thing that will keep us from washing away the mountains into the sea in the future.
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RogerMay 4th, 2007 - 14:54:33
Come along anti-warmers, spout all your usual clap-trap about ice ages appearing next week and how everybody gas got it wrong - except yourselves, of course, who have divine insight without any reliable evidence except that cooked up by the 'scientists' funded by the oil industry
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