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Summary
The Southern Oscillation and the solar cycle have significant effects on year-to-year global temperature change. Because both of these natural effects were in their cool phases in 2007, the unusual warmth of 2007 is all the more notable. It is apparent that there is no letup in the steep global warming trend of the past 30 years (see 5-year mean curve in Figure 1a).
"Global warming stopped in 1998," has become a recent mantra of those who wish to deny the reality of human-caused global warming. The continued rapid increase of the five-year running mean temperature exposes this assertion as nonsense.
In reality, global temperature jumped two standard deviations above the trend line in 1998 because the "El Niño of the century" coincided with the calendar year, but there has been no lessening of the underlying warming trend.
One thing I've certainly been thinking is that, in a scenario very familiar to share traders, the whole global warming thing does seem to have undergone a parabolic rise and possible blow off top in the past year or so. That it came amidst falling temperatures does reek of a desperate "now or never" stance being taken.
IMO 10 years from now the issue will be largely ignored no matter what the science. Oil shortages will be the focus then and that one is real.
Ground based thermometers near cities or industry are essentially useless due to localised effects.By Juliet Eilperin
Washington Post Staff Writer
Friday, August 4, 2006; Page A03
Heat waves like those that have scorched Europe and the United States in recent weeks are becoming more frequent because of global warming, say scientists who have studied decades of weather records and computer models of past, present and future climate.
While it is impossible to attribute any one weather event to climate change, several recent studies suggest that human-generated emissions of heat-trapping gases have produced both higher overall temperatures and greater weather variability, which raise the odds of longer, more intense heat waves.
Waynel it would be good if you could quote the NASA reports
Possible. But industrial scale farming is simply a means of converting oil, gas and a bit of electricity into something humans can eat. If you look at the total energy input to a meal on your table then actual crop growing is very much in the minority. No oil = no food, at least not enough for 6 billion people.Maybe, but you cant eat oil. The rice problem due to drought is not looking the best, if it continues then in 10 years time perhaps our hunger will make us forget about oil.
I know of very few people that don't view global warming as 100% proven fact. Those that don't take this view tend to be the type that are into alternative medicines, work out at gyms and are generally not big followers of mainstream news media. Also those with some reason, such as employment or an interest in science, to have thoroughly investigated the issue. Other than that small bunch, the rest take it as fact beyond question.Are those of us engaging in this discussion here on ASF typical of the general population? Or do Mr and Mrs Average really only worry about what they want to watch on television tonight and who will win the footy?
I guess what I'm wondering is how much time and emotional effort we are all expending on actually worrying about global stuff (other than financially related markets of course). Is it just the time it takes to type out a post on this thread, or are members seriously thinking about it for much of their time?
Global warming true believers have spent the last few years denying that sunspots affected global temperature, because admitting this fact would undermine all the "models" attributing historic temperature rises to CO2.
It isn't possible to pin the recent low temperatures on sunspots without also pinning historical rises in temperature to the same cause.
You can't have your cake and eat it to, attributing all falls in temperature to sunspots, and all rises in temperature to CO2.
Possible. But industrial scale farming is simply a means of converting oil, gas and a bit of electricity into something humans can eat. If you look at the total energy input to a meal on your table then actual crop growing is very much in the minority. No oil = no food, at least not enough for 6 billion people.
1.No, anyone who has read a paragraph or two about this will know that the sun affects the earth's temperature. And no-one has “spent the last few years denying this” (except the no-hopers I guess). The question becomes, what about the excessive increase in temperature that cannot be (almost certainly – like 95% + certain) explained by natural phenomena (sun, atmospheric/volcanic dust, etc).1.Global warming true believers have spent the last few years denying that sunspots affected global temperature, because admitting this fact would undermine all the "models" attributing
2.......historic temperature rises to CO2.
3.It isn't possible to pin the recent low temperatures on sunspots without also pinning historical rises in temperature to the same cause.
4.You can't have your cake and eat it to, attributing all falls in temperature to sunspots, and all rises in temperature to CO2.
anyone who has read a paragraph or two about this will know that the sun affects the earth's temperature
http://environment.newscientist.com/channel/earth/climate-change/dn11650... Show me one report on climate change that considers the impact of sunspots.
Sunspot trouble
So what role, if any, have solar fluctuations had in recent temperature changes? While we can work out how Earth's orbit has changed going back many millions of years, we have no first-hand record of the changes in solar output associated with sunspots before the 20th century.
It is true that sunspot records go back to the 17th century, but sunspots actually block the Sun's radiation. It is the smaller bright spots (faculae) that increase the Sun's output and these were not recorded until more recently. The correlation between sunspots and bright faculae is not perfect, so estimates of solar activity based on sunspot records may be out by as much as 30%.
The other method of working out past solar activity is to measure levels of carbon-14 and beryllium-10 in tree rings and ice cores. These isotopes are formed when cosmic rays hit the atmosphere, and higher sunspot activity is associated with increases in the solar wind that deflect more galactic cosmic rays away from Earth. Yet again, though, the correlation is not perfect. What is more, recent evidence suggests that the deposition of beryllium-10 can be affected by climate changes, making it even less reliable as a measure of past solar activity.
Recent rises
Despite these problems, most studies suggest that before the industrial age, there was a good correlation between natural “forcings" – solar fluctuations and other factors such as the dust ejected by volcanoes – and average global temperatures. Solar forcing may have been largely responsible for warming in the late 19th and early 20th century, levelling off during the mid-century cooling (see Global temperatures fell between 1940 and 1980).
The 2007 IPCC report halved the maximum likely influence of solar forcing on warming over the past 250 years from 40% to 20%. This was based on a reanalysis of the likely changes in solar forcing since the 17th century.
But even if solar forcing in the past was more important than this estimate suggests, as some scientists think, there is no correlation between solar activity and the strong warming during the past 40 years. Claims that this is the case have not stood up to scrutiny (pdf document).
Direct measurements of solar output since 1978 show a steady rise and fall over the 11-year sunspot cycle, but no upwards or downward trend .
Similarly, there is no trend in direct measurements of the Sun's ultraviolet output and in cosmic rays. So for the period for which we have direct, reliable records, the Earth has warmed dramatically even though there has been no corresponding rise in any kind of solar activity.
Factors that warm or cool the planet
AR4 describes warming and cooling effects on the planet in terms of radiative forcing ”” the rate of change of energy in the system, measured as power per unit area (in SI units, W/m ²). The report shows in detail the individual warming contributions (positive forcing) of carbon dioxide, methane, nitrous oxide, halocarbons, other human warming factors, and the warming effects of changes in solar activity. Also shown are the cooling effects (negative forcing) of aerosols, land-use changes, and other human activities. All values are shown as a change from pre-industrial conditions.
Total radiative forcing from the sum of all human activities is a warming force of about +1.6 watts/m ²
Radiative forcing from an increase of solar intensity since 1750 is about +0.12 watts/m ²
Radiative forcing from carbon dioxide, methane, and nitrous oxide combined is very likely (>90%) increasing more quickly during the current era (1750-present) than at any other time in the last 10,000 years.
I cant believe we have 3 pages of an ice age thread and no mention of the North Atlantic conveyor and its predicted demise....thus new ice age.
Climate myths: Warming will cause an ice age in Europe
While the rest of Earth swelters, might Europe and parts of North America freeze? This scenario was always unlikely, and the latest findings largely rule it out.
Europe and parts of North America are kept milder than other northerly parts by warm water flowing north from the Caribbean in an ocean current called the North Atlantic Drift. If climate change broke this heating system, European temperatures could drop by up to 5 °C or more within decades.
Some have even talked of a new ice age, of tundra spreading across the continent, while the film The Day After Tomorrow depicted the Earth plunging into a super ice age within weeks (see Scientists stirred to ridicule ice age claims).
Well, global warming certainly could disturb ocean currents. They are largely driven by the sinking of cold, salty water in the Arctic, but melting glaciers and swollen rivers are now pouring more fresh water into the surface of the Arctic ocean than before. Fresh water is less dense than salty, so it weakens this "pump". Enough could hinder ocean circulation, or even cut it off, as may have happened in the past.
In 2005, climatologists were shocked by evidence that it was already happening. A team of oceanographers led by Harry Bryden of Southampton University, UK, claimed there was a 30% reduction in the vital Atlantic current. But subsequent measurements by the team show no clear trend.
Few scientists think there will be a rapid shutdown of circulation. Most ocean models predict no more than a slowdown, probably towards the end of the century. This could slow or even reverse some of the warming due to human emissions of greenhouse gases, which might even be welcome in an overheated Europe, but the continent is not likely to get colder than it is at present.
A slowdown in circulation would affect many parts of the world by disrupting global rainfall patterns. But these effects will be insignificant compared with the much greater changes global warming will cause
There is also a guide to assessing the evidence. In the articles we've included lots of links to primary research and major reports for those who want to follow through to the original sources.
Can we trust the science?
• Chaotic systems are not predictable
• We can't trust computer models of climate
• Many leading scientists question climate change
• It's all a conspiracy
• They predicted global cooling in the 1970s
Is the sun to blame?
• Global warming is down to the Sun, not humans
• It’s all down to cosmic rays
Does CO2 cause warming?
• Human CO2 emissions are too tiny to matter
• CO2 isn't the most important greenhouse gas
• Ice cores show CO2 increases lag behind temperature rises, disproving the link to global warming
• Ice cores show CO2 rising as temperatures fell
• The cooling after 1940 shows CO2 does not cause warming
What happened in the past?
• The 'hockey stick' graph has been proven wrong
• It's been far warmer in the past, what's the big deal?
• It was warmer during the Medieval period, with vineyards in England
• We are simply recovering from the Little Ice Age
What is happening now?
• Mars and Pluto are warming too
• Antarctica is getting cooler, not warmer, disproving global warming
• Polar bear numbers are increasing
• The lower atmosphere is cooling, not warming
• The oceans are cooling
What is going to happen?
• Warming will cause an ice age in Europe
• Higher CO2 levels will boost plant growth and food production
• Hurricane Katrina was caused by global warming
Why should I worry?
• It's too cold where I live - warming will be great
• We can't do anything about climate change
...North Atlantic conveyor and its predicted demise....thus new ice age.
http://en.wikipedia.org/wiki/Gulf_Stream
There is some speculation that global warming could decrease or shutdown thermohaline circulation and therefore reduce the North Atlantic Drift. The timescale that this might happen in is unclear; estimates range from a few decades to a few hundred years[1]. This could trigger localised cooling in the North Atlantic and lead to cooling (or lesser warming) in that region, particularly affecting areas that are warmed by the North Atlantic Drift, such as Scandinavia and Great Britain.[7] The chances of this occurring are unclear.[8]
At present, most available data show that Gulf Stream flow was stable over the past 40 years.[9] One report, based on a snapshot survey, suggested that the deep return flow has weakened[10] by 30% since 1957, which would imply a weakening in the North Atlantic Deep Water production.[11] However, this should have caused a temperature drop of several degrees in northwest Europe, but instead temperatures have tended to increase.
It was later discovered, using the first cross-Atlantic array of moored current meters, that variations within one year were just as large.[12]
It has been reported by several news media[13][14] in late 2006 that in november 2004 the gulf stream stopped entirely for ten days. At least part of the apparent weakening of the Gulf Stream (if real) may be cyclical and connected to recent positive values of North Atlantic Oscillation.[15] Recent research[16] shows that Gulf Stream volume transport during the Little Ice Age was ten percent weaker than today’s, implying that diminished oceanic heat transport may have contributed to the 16th- to the mid-19th-century cooling in the North Atlantic.
Researchers are not sure yet what to make of the 10-day hiatus. "We'd never seen anything like that before and we don't understand it. We didn't know it could happen," said Harry Bryden, at the National Oceanography Centre, in Southampton, who presented the findings to a conference in Birmingham on rapid climate change.
Is it the first sign that the current is stuttering to a halt? "I want to know more before I say that," Professor Bryden said.
Lloyd Keigwin, a scientist at the Woods Hole Oceanographic Institution, in Massachusetts, in the US, described the temporary shutdown as "the most abrupt change in the whole [climate] record".
Prof Bryden's group stunned climate researchers last year with data suggesting that the flow rate of the Atlantic circulation had dropped by about 6m tonnes of water a second from 1957 to 1998. If the current remained that weak, he predicted, it would lead to a 1C drop in the UK in the next decade. A complete shutdown would lead to a 4C-6C cooling over 20 years.
The study prompted the UK's Natural Environment Research Council to set up an array of 16 submerged stations spread across the Atlantic, from Florida to north Africa, to measure flow rate and other variables at different depths. Data from these stations confirmed the slowdown in 1998 was not a "freak observation"- although the current does seem to have picked up slightly since.
Wayne you posted this in response to the Tasman Glacier comments ..The world's climate must be taken as a whole to discuss global warming/cooling. Single incidences may have other local factors at play... deforestation, heat sink effect, el niño/la niña, whatever.
On a whole the world has been getting cooler over the last decade... and that's from the likes of NASA etc.
NASA continues to a summary :-
http://data.giss.nasa.gov/gistemp/2007/
Summary
The Southern Oscillation and the solar cycle have significant effects on year-to-year global temperature change. Because both of these natural effects were in their cool phases in 2007, the unusual warmth of 2007 is all the more notable. It is apparent that there is no letup in the steep global warming trend of the past 30 years (see 5-year mean curve in Figure 1a).
"Global warming stopped in 1998," has become a recent mantra of those who wish to deny the reality of human-caused global warming. The continued rapid increase of the five-year running mean temperature exposes this assertion as nonsense.
In reality, global temperature jumped two standard deviations above the trend line in 1998 because the "El Niño of the century" coincided with the calendar year, but there has been no lessening of the underlying warming trend.
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