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Study Finds World Warmth Edging to Ancient Levels
Krishna Dagli writes to mention a decades-long study by NASA scientists. According to the research, global temperatures are reaching highs not seen in thousands of years. From the article: "One of the findings from this collaboration is that the Western Equatorial Pacific and Indian Oceans are now as warm as, or warmer than, at any prior time in the Holocene. The Holocene is the relatively warm period that has existed for almost 12,000 years, since the end of the last major ice age. The Western Pacific and Indian Oceans are important because, as these researchers show, temperature change there is indicative of global temperature change. Therefore, by inference, the world as a whole is now as warm as, or warmer than, at any time in the Holocene. According to Lea, 'The Western Pacific is important for another reason, too: it is a major source of heat for the world's oceans and for the global atmosphere.'"
If you haven't seen An Inconvenient Truth, yet, do try. Like Al Gore, it's a bit clunky, but there's a lot of truth in there and shouldn't be discounted just because you may not like the presenter.
My belief is, we'll keep right on going in this direction until we feel sufficient pain* to stop. Famine and flooding will certainly increase the likelihood of conflict. Darfur as depicted in the film was an eye opener, the severe drought which may be caused by warming now appears more likely the root of conflict as people scrabble for remaining water and land.
It may become the view that USA and Europe, have had it good long enough and they should cut down on emissions first. It will come to a head when cities like Shanghai are under water and each country is blaming the other for the fine mess things are in. Those who have dipped deepest and longest into the carbon fuels trough the will have an uncomfortable time of it.
A feeling of having made the same mistake before: Deja Foobar
NASA Study Finds World Warmth Edging Ancient Levels
Sep. 25, 2006
A new study by NASA scientists finds that the world's temperature is reaching a level that has not been seen in thousands of years.
The study, led by James Hansen of NASA's Goddard Institute for Space Studies, N.Y., along with scientists from other organizations concludes that, because of a rapid warming trend over the past 30 years, the Earth is now reaching and passing through the warmest levels in the current interglacial period, which has lasted nearly 12,000 years. An "interglacial period" is a time in the Earth's history when the area of Earth covered by glaciers was similar or smaller than at the present time. Recent warming is forcing species of plants and animals to move toward the north and south poles.
Image right: Because of a rapid warming trend over the past 30 years, the Earth is now reaching and passing through the warmest levels seen in the last 12,000 years. This color-coded map shows average temperatures from 2001-2005 compared to a base period of temperatures from 1951-1980. Dark red indicates the greatest warming and purple indicates the greatest cooling. Click image to enlarge. Credit: NASA
The study used temperatures around the world taken during the last century. Scientists concluded that these data showed the Earth has been warming at the remarkably rapid rate of approximately 0.36 Fahrenheit (0.2 Celsius) per decade for the past 30 years.
"This evidence implies that we are getting close to dangerous levels of human-made pollution," said Hansen. In recent decades, human-made greenhouse gases have become the largest climate change factor. Greenhouse gases trap heat in the Earth's atmosphere and warm the surface. Some greenhouse gases, which include water vapor, carbon dioxide, methane, nitrous oxide, and ozone, occur naturally, while others are due to human activities.
Image left: Because of a rapid warming trend over the past 30 years, the Earth is now reaching and passing through the warmest levels seen in the last 12,000 years. This color-coded map shows a progression of changing global surface temperatures from 1880 to 2005, the warmest ranked year on record. Dark red indicates the greatest warming and dark blue indicates the greatest cooling. Click image to view animation. Credit: NASA
The study notes that the world's warming is greatest at high latitudes of the Northern Hemisphere, and it is larger over land than over ocean areas. The enhanced warming at high latitudes is attributed to effects of ice and snow. As the Earth warms, snow and ice melt, uncovering darker surfaces that absorb more sunlight and increase warming, a process called a positive feedback. Warming is less over ocean than over land because of the great heat capacity of the deep-mixing ocean, which causes warming to occur more slowly there.
Hansen and his colleagues in New York collaborated with David Lea and Martin Medina-Elizade of UCSB to obtain comparisons of recent temperatures with the history of the Earth over the past million years. The California researchers obtained a record of tropical ocean surface temperatures from the magnesium content in the shells of microscopic sea surface animals, as recorded in ocean sediments.
Image left: Data from this study reveal that the Earth has been warming approximately 0.2 degrees Celsius (0.36 Fahrenheit) per decade for the past 30 years. This rapid warming has brought global temperature to within about one degree Celsius (1.8 degrees Fahrenheit) of the maximum estimated temperature during the past million years. Credit: NASA
One of the findings from this collaboration is that the Western Equatorial Pacific and Indian Oceans are now as warm as, or warmer than, at any prior time in the Holocene. The Holocene is the relatively warm period that has existed for almost 12,000 years, since the end of the last major ice age. The Western Pacific and Indian Oceans are important because, as these researchers show, temperature c
http://en.wikipedia.org/wiki/Temperature_record_of _the_past_1000_years#General_techniques
It probably took you longer to post that question than it took me to find that answer.
=Smidge=
The article only actually mentions climate change within the past million years. Measuring temperatures over ththis period is relatively easily done by measuring the makeup of dissolved gas within ice deposits from the period. The gas composition is affected by the temperature at the time the ice freezes so by compiling many samples an extremely accurate climate chart can be put together.
To some extent it is also possible to measure even longer trends of several millions years using a few methods which have varying degrees (haha) of accuracy. Studying the geological effects on rock (i.e. calculating sea level height by erosion caused on rocks which were on the surface at a known point in time) is one of the most common.
Ever wonder How fast a normal climate change occurs ?. stmRead this first
BTW : http://news.bbc.co.uk/2/hi/science/nature/5357606
Yes, I'm left. You have a problem with that?
Just to clarify, when I read your post, this is what I think you're saying:
that it would raise temperatures in the past as well!
Because 12,000 years ago, the temperature was as high as current measurements. You are saying that if US emissions of CO2 are the cause of the current rise in temperature, it must be the cause of the ancient high temperatures as well.
This is the kind of information that I try to show
You show them what? A slashdot article? I take it you give them verbal statements alone, such as this one.
I'm not saying that pollution is okay, but I do think that it has less to do with long term global climate shifts than others would have you believe.
Are you referring to the Big Tobacco article? Some would tell me there is no global warming. Others would tell me the world is about to end. Some even tell me that tobacco companies want me to believe there is no global warming.
That's what I mean when I say, "The debate is heating up!"
More data equals more confidence. If you dredge up thousands and thousands of ice cores, mud cores or what have you, take all the data and plot a histogram of it, you usually get a nice bell shaped curve. If you've got lots and lots and lots and lots of data, which these guys do, you can safely say that the middle of the bell curve is the mean of your data.
Of course, as you mention, there is a margin of error. However, by a happy chance of mathematics, the more data you get, the more confident you become that the temperature was within so many standard deviations of the mean. The bell curve won't change shape, in fact you want it to stay the same. And if it does, that means, on average, the temperature or whatever was in and around the mean value.
Basically if you get enough data, i.e. do enough experiments, you can tell the doubters to stick their unsubstanciated opinion where the maths don't shine.
May the Maths Be with you!
If a job's not worth doing, it's not worth doing right.
A. The earth's orbit is elliptical. Not only is it an ellipse but the eccentricity, or variance from being circular, is not constant.
2 0Images/Spirograph%203D.JPG, which has a cycle of approximately 26,000 years.
B. The earth's orbit and the earth's axial rotation when in this orbit begins to resemble a spirograph http://physics.indstate.edu/west/zoorings/ThreeD%
C. Milankovitch cycles http://en.wikipedia.org/wiki/Milankovitch_cycles explain: "The eccentricity, axial tilt, and precession of the Earth's orbit vary in several patterns, resulting in 100,000 year ice age cycles of the Quaternary glaciation over the last few million years."
D. Earth's climate graph shows no distinct pattern. Earth's glacial coverage has gone from historic minimum to maximum in the period of 100 years. It is nonsense to claim that our temperature will continue to rise or even fall for that matter. It is a flip of a coin.
I do not concur with human-caused global warming. I feel it is hysteric, unfounded, and egocentric. I also do not bother watching media hype movies starring washed up politicians who claim they are making a documentary while ignoring an entire side of the debate.
Anything can, could, and will happen.
From the article:
What the article fails to mention is that the entire human contribution to global warming is about half a degree Celsius. (0.48 C http://data.giss.nasa.gov/gistemp/2004/) So we have a ways to go before everyone dies.
The problem is that this system has a bit of momentum to it. Currently we're on a train barreling down the tracks and some guy with binoculars has just told us the bridge is out ahead, and we're still pushing forward. But we're not pushing quite as hard as we were, and that seems like progress to me.
It makes sense because we are being told that humans are causing the temps to "explode" over the last hundred years or so. But how then could the temps be warmer 10+K years ago? Why were the temps so high back then?
They weren't - they were colder. All they're saying is that they've examined evidence of temperatures over that period, and this is the warmest time in the entire period. They haven't reached any definite conclusions about earlier periods, although their tentative conclusions are that now is the warmest time since a lot more than 12,000 years ago (I think the tentative conclusions covered hundreds of thousands of years).
From TFA:
At current rates of warming, we will pass that stage in a little over 30 years, however the rate is not constant, it is accelerating. Accounting for the acceleration we could discount to 20 years or less. So what they're saying is that 2 years from now we are likely to have average temperatures not seen in 3 million years.
RealClimate.org is an excellent source for busting the myths that appear with nauseating regularity in every climate related thread on slashdot.
RealClimate was started and is run by some of the best climate researchers on the planet, the study in TFA is by Hansen, yet another respected scientist that claims politicians have recently attempted to gag him.
The scientists predicted an ice age myth was made popular by a novel (ie: a work of fiction). A certain senator was so impressed with the novel that he intoduced the authour to a senate committee as an "expert on climate change" and asked him to advise them on the subject.
And did you exchange a walk on part in the war for a lead role in a cage? - Pink Floyd.
1) Do we, as a species, WANT global temperatures to reach levels not seen since the Holocene period ?
The holocene period is the period since the last ice age and temperatures are still moving towards the maximum of this interglacial. The global temperatures have been gradually rising during the entire holocene. In some interglacials before the previous, exceptionally cold ice age, global temperatures were slightly higher than they are now, and lions and forest elephants were to be found in northern Europe. The end of the last ice age caused extinctions, as did its beginning.
The cycle of ice ages is almost certainly not over. This inter glacial period called the holocene will inevitably keep warming up, until it reaches a maximum, after which it will gradually cool down again until glaciers cover Northern Europe, Canada and Siberia again. If there is a human influence, it is certainly not the only one.
I am not one of these anti-environment right-wingers, but the debate on human-caused global warming is not just one of smart, responsible people vs stupid, conservative people. A causal relation was found between pollution -> acid rain -> dying forests and lakes; therefor reducing SO2 emissions has been noticeably improving this situation (there's a long way to go though). A mechanism was found linking CFC's with the hole in the ozone layer; therefor investing in reducing CFC emissions was a sensible thing to do, and we are already beginning to see the results. There is no clear mechanism for increased CO2 levels leading to climate change. Ice core samples have shown a relationship between CO2 levels and temperatures, but the causal relationship also goes the other way: a rise in temperature also causes an increase in CO2 levels through increased biological activity. In how far have CO2 levels been the cause and in how far the effect of global warming in the past?