Global Warming Spam

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tasoli

Guest
Global Warming Report, Part 1



Getting warmer?


Global warming is one hot topic--and, in the United States at least, the cause of heated political debate. So, last year, Congress asked the National Research Council--whose members come straight from the National Academy of Sciences, National Academy of Engineering, and Institute of Medicine--to review all the science and answer two questions: How has temperature varied over the last 2,000 years? How certain is the answer to this question?

Last week, the National Research Council's panel of experts published their 142-page response, titled Surface Temperature Reconstructions for the Last 2,000 Years. Here are the highlights. We'll have even more in our next issue.

No Fake Bake

"The Earth warmed by roughly 0.6 degrees Centigrade (1 degree Fahrenheit) during the 20th century, and is projected to warm by an additional ~2-6 degrees C during the 21st century."


"Widespread, reliable instrumental records are available only for the last 150 years or so. To study how climatic conditions varied prior to the time of the Industrial Revolution, paleoclimatologists rely on proxy evidence such as tree rings, corals, ocean and lake sediments, cave deposits, fossils, ice cores, borehole temperatures, glacier length records, and documentary evidence."


"Proxy records are meaningful recorders of environmental variables. . . . The connections between proxy records and environmental variables are well justified in terms of physical, chemical, and biological processes."


"The warming is also reflected in a host of other indicators: glaciers are retreating, permafrost is melting, snowcover is decreasing, Arctic sea ice is thinning, rivers and lakes are melting earlier and freezing later, bird migration and nesting dates are changing, flowers are blooming earlier, and the ranges of many insect and plant species are spreading to higher latitudes and higher elevations."
Consistent Climatic Conclusions

"Large-scale surface temperature reconstructions yield a generally consistent picture of temperature trends during the preceding millennium, including relatively warm conditions centered around A.D. 1000 (identified by some as the 'Medieval Warm Period') and a relatively cold period (or 'Little Ice Age') centered around 1700."


"It can be said with a high level of confidence that global mean surface temperature was higher during the last few decades of the 20th century than during any comparable period during the preceding four centuries. This statement is justified by the consistency of the evidence from a wide variety of geographically diverse proxies."


"Less confidence can be placed in large-scale surface temperature reconstructions for the period from A.D. 900 to 1600. Presently available proxy evidence indicates that temperatures at many, but not all, individual locations were higher during the past 25 years than during any period of comparable length since A.D. 900."


"Very little confidence can be assigned to statements concerning the hemispheric mean or global mean surface temperature prior to about A.D. 900 because of sparse data coverage and because the uncertainties associated with proxy data . . . are larger than during more recent time periods."
The Proxies Point to Heat

Tree rings - "Measurements of tree ring parameters from regions where temperature limits tree growth can be used to reconstruct surface temperature. These show that the 20th century warming is unusual since at least 1500."


Marine, lake, and cave proxies - "Annual coral records indicate a warming and/or freshening of surface seawater over the last century at most tropical locations, as well as shifts toward warmer and/or fresher waters during the mid-1800s and between 1920 and 1940."


Ice isotopes - "Analyses of stable isotopes in glacial ice provide records of climate changes at high resolution over long time periods. . . . Isotope records from Tibet and the Andes show that the climate of the 20th century was unusual with respect to the preceding 2,000 years."


Glacier length - "Records of glacier length can be used to infer temperature history. These records show global warming of approximately 0.6 degrees C from 1850 to 1990 and cooler conditions for the prior few centuries. The majority of glaciers in high mountain ranges outside the polar regions have retreated during the last 150 years, primarily as a consequence of warming."


Boreholes - "When the temperature at the ground surface changes, the temperature of the underlying substrate (soil, rock, or ice) will also change in response. . . . Measurements of temperature beneath the ground surface show widespread warming during the most recent century and cooler conditions for the four prior centuries."
Michael Himick and Steve Sampson
June 26, 2006
 
T

tasoli

Guest
Global Warming Report, Part 2



What's the reason
for our hot season?


Last issue, we reviewed the National Research Council's report to Congress on "Surface Temperature Reconstructions for the Last 2,000 Years." That report, released last week, found that the world is in fact getting warmer--warmer than it's been in at least 400 years.

So, now what? Well, the report didn't make policy recommendations, nor did it focus at length on the more complicated question of why we're getting warmer. But it did briefly summarize the state of that science. Here are those highlights, plus a guide to global warming resources on the web so you can learn more.

It's Warmer--But Why?

"The temperature of the Earth is determined by a balance of the energy entering the Earth-atmosphere system and the energy leaving the system. An energy imbalance imposed on the climate system either externally or by human activities is termed a climate forcing; persistent climate forcings cause the temperature of the Earth to change until an energy balance is restored."


"The main external climate forcings experienced over the last 2,000 years are volcanic eruptions, changes in solar radiation reaching the Earth, and increases in atmospheric greenhouse gases and aerosols due to human activities."


"Volcanic activity has not been anomalous as compared to the last 1,000 years and cannot be used to explain the late 20th century warmth."


"On the basis of satellite-based monitoring, which began in the late 1970s, it is clear that the rapid global warming of the last few decades is not attributable to an increase in the Sun's emission."
Science Guesses Greenhouse Gases

"Since the beginning of the Industrial Revolution (ca. 1750), the concentrations of greenhouse gases in the atmosphere have increased considerably. . . . Carbon dioxide has increased from about 280 ppm during preindustrial times to current values of around 380 ppm. Methane has more than doubled from preindustrial levels, with more moderate but significant increases of nitrous oxide."


"The radiative forcing due to the increases of these and other long-lived greenhouse gases . . . is significantly larger than any variations or trends in the natural forcings as we understand them over the last 2,000 years."


"Climate model simulations indicate that solar and volcanic forcings together could have produced periods of relative warmth and cold during the preindustrial portion of the last 1,000 years. However, anthropogenic greenhouse gas increases are needed to simulate late 20th century warmth."


"The numerous indications that recent warmth is unprecedented for at least the last 400 years and potentially the last several millennia, in combination with estimates of external climate forcing variations over the same period, support the conclusion that human activities are responsible for much of the recent warming."
Steve Sampson and Michael Himick
June 27, 2006
 

Karetyr

Cadet
Sigh.

Even if the ice caps completely melted instantaneously, I seriously doubt we'd have any greater problems than perhaps a little coastal adjustment (we don't really need Florida anyway).
 
Originally posted by Riceman@Jun 29 2006, 09:34 PM
Sigh.

Even if the ice caps completely melted instantaneously, I seriously doubt we'd have any greater problems than perhaps a little coastal adjustment (we don't really need Florida anyway).
The fresh water would make a lot of the earth freeze over because it would stop the conveyor thingy that heats up the earth with the ocean's help..
 
T

tasoli

Guest
Originally posted by frostydf2@Jun 29 2006, 02:59 PM
GAH not this again! Tasoli!
I'm just highlighting an e-mail I got, not trying to prove a point. I didn't write this, if you read the end it says who wrote it.
 

Karetyr

Cadet
Originally posted by HJ-Diviana+Jun 29 2006, 08:43 PM--></div><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (HJ-Diviana @ Jun 29 2006, 08:43 PM)</td></tr><tr><td id='QUOTE'> <!--QuoteBegin-Riceman@Jun 29 2006, 09:34 PM
Sigh.

Even if the ice caps completely melted instantaneously, I seriously doubt we'd have any greater problems than perhaps a little coastal adjustment (we don't really need Florida anyway).
The fresh water would make a lot of the earth freeze over because it would stop the conveyor thingy that heats up the earth with the ocean's help.. [/b][/quote]
You're talking about the north atlantic current, yes? You ARE aware that The Day After Tomorrow was based on pseudo-science, right?
 
Originally posted by Riceman+Jun 30 2006, 09:43 AM--></div><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (Riceman @ Jun 30 2006, 09:43 AM)</td></tr><tr><td id='QUOTE'>
Originally posted by HJ-Diviana@Jun 29 2006, 08:43 PM
<!--QuoteBegin-Riceman
@Jun 29 2006, 09:34 PM
Sigh.

Even if the ice caps completely melted instantaneously, I seriously doubt we'd have any greater problems than perhaps a little coastal adjustment (we don't really need Florida anyway).

The fresh water would make a lot of the earth freeze over because it would stop the conveyor thingy that heats up the earth with the ocean's help..
You're talking about the north atlantic current, yes? You ARE aware that The Day After Tomorrow was based on pseudo-science, right? [/b][/quote]
Is that a movie?

I don't like most movies so I don't watch them.. So I can't relate when people talk about them half the time. Then if I have seen the movie, most of those I totally forgot what happened, who was in it, what it was about, the title, etc.

Anyway.

I am talking about Thermohaline Circulation (aka ocean conveyor belt).

To say just the North Atlantic current leaves out the entire rest of the oceans. This is a global thing.
 

Pietoro

Cadet
Thing is, the icecaps, when FROZEN -displace the same amount of water- whether or not they're liquid or solid. So them melting wouldn't raise the coasts as much as sci-fi films would like you to believe. Its basic physics.

Its more of the -collapse of the gulfstream- and the change in weather patterns which would in turn, drastically alter ecosystems and cause mass extinctions, that is the worry of global warming. Tidal waves engufing cities is really not that realistic.
 
T

tasoli

Guest
Originally posted by Pietoro@Jul 1 2006, 09:29 PM
Thing is, the icecaps, when FROZEN -displace the same amount of water- whether or not they're liquid or solid. So them melting wouldn't raise the coasts as much as sci-fi films would like you to believe. Its basic physics.

Its more of the -collapse of the gulfstream- and the change in weather patterns which would in turn, drastically alter ecosystems and cause mass extinctions, that is the worry of global warming. Tidal waves engufing cities is really not that realistic.
To quote someone from another website...
"Since the icecap mentioned is actually on land right now, if it melted into the ocean, the levels would rise, by a lot more than 23 feet. Think of it like this, an icecube melting in a cup won't add to the level of water in the cup, but an ice cube melting on a counter, with the resulting water draining into the cup will effect the cup's water level. Fortunately, the Antarctic icecap has been increasing over recent decades, so I am no worride about Las Vegas becoming beach front property."

The ice caps aren't all floating, some of them are on a "land shelf"- AKA there is solid land beneath them, and they're not floating, hence not displacing any water, and will effect water level of the sea.
 
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