Climate Change and Civilization

[Beagle]

Actual question Essan:

Do you know a formula that would show the amount of H20 expansion per degree of temperature increase?

Thanks either way.

[Essan]

Actual question Essan:

Do you know a formula that would show the amount of H20 expansion per degree of temperature increase?

Thanks either way.

How about this:-

Saltwater continues to become more dense as it cools to the freezing point; freshwater reaches maximum density at
4°C and then expands (becomes less dense) as the water cools to 0°C and freezes. This means that the convective
mixing of freshwater stops at 4°C; freezing proceeds very rapidly beyond that point. The rate of expansion
with increased temperature is greater in seawater than in fresh water. Thus, at temperature 15°C, and atmospheric
pressure, the coefficient of thermal expansion is 0.000151 per degree Celsius for freshwater, and 0.000214 per degree Celsius for average seawater. The coefficient of thermal expansion increases not only with greater salinity, but also with increased temperature and pressure. At a salinity of 35 psu, the coefficient of surface water increases from 0.000051 per degree Celsius at 0°C to 0.000334 per degree Celsius at 31°C. At a constant temperature of 0°C and a salinity of 34.85 psu, the coefficient increases to 0.000276 per degree Celsius at a pressure of 10,000 decibars (a depth of approximately 10,000 meters).

http://ioc.unesco.org/oceanteacher/ocea ... apt-31.pdf


Of course, it's further complicated with increased evapouration leading to increased salinity; increased rainfall would reduce salinity where it falls over the oceans, but higher rianfall over land would increase erosive rates and mean more minerals being washed into the oceans and hence more salinity. . And I'm not sure if all this extra water vapour in the atmosphere would lead to increased atmospheric pressure too?

Bit complicated innit

Hmmm, wouldn't a warmer world actually result in less cloud cover? Water vapour needs to cool to condense into clouds ...

[Guest]

Sure Essan, everybody knows that warmer ocean water surfaces (from contact with warmer air) results in less evaporation off the ocean, so less cloud-cover, yeh, that's the ticket.

[Essan]

More evapouration occus on a sunny day than a cloudy one. You can p[rove that yourself by leaving a bowl of water outside and watching the results

Of course, wind is also a factor. Would total cloud cover result in less cyclogenesis and reduced storm activity? Or more? If the temperature differential between tropics and poles is less than it should mean less storms so lighter winds....

[Guest]

You go boy.

[Beagle]

Actual question Essan:

Do you know a formula that would show the amount of H20 expansion per degree of temperature increase?

Thanks either way.

How about this:-

Saltwater continues to become more dense as it cools to the freezing point; freshwater reaches maximum density at
4°C and then expands (becomes less dense) as the water cools to 0°C and freezes. This means that the convective
mixing of freshwater stops at 4°C; freezing proceeds very rapidly beyond that point. The rate of expansion
with increased temperature is greater in seawater than in fresh water. Thus, at temperature 15°C, and atmospheric
pressure, the coefficient of thermal expansion is 0.000151 per degree Celsius for freshwater, and 0.000214 per degree Celsius for average seawater. The coefficient of thermal expansion increases not only with greater salinity, but also with increased temperature and pressure. At a salinity of 35 psu, the coefficient of surface water increases from 0.000051 per degree Celsius at 0°C to 0.000334 per degree Celsius at 31°C. At a constant temperature of 0°C and a salinity of 34.85 psu, the coefficient increases to 0.000276 per degree Celsius at a pressure of 10,000 decibars (a depth of approximately 10,000 meters).

http://ioc.unesco.org/oceanteacher/ocea ... apt-31.pdf


Of course, it's further complicated with increased evapouration leading to increased salinity; increased rainfall would reduce salinity where it falls over the oceans, but higher rianfall over land would increase erosive rates and mean more minerals being washed into the oceans and hence more salinity. . And I'm not sure if all this extra water vapour in the atmosphere would lead to increased atmospheric pressure too?

Bit complicated innit

Hmmm, wouldn't a warmer world actually result in less cloud cover? Water vapour needs to cool to condense into clouds ...

Thanks Essan, this will be quite helpful.

I'm interested in sea level expansion/rise, not dense cloud cover.
Fact not fiction.

[oldarchystudent]

Being English by birth I found this interesting. Again I wonder how many pre-historic sites are drowned at the bottom of the North Sea. The rivers look like prime migration routes.

Jim

[Beagle]

http://presszoom.com/story_118537.html

(PressZoom) - Using chemical traces in fossil shells of microscopic planktonic life forms, called formanifera, in deep-sea sediment cores, scientists reconstructed a 45,000- to 60,000-year-old record of ocean temperature and salinity. They compared their results to the record of abrupt climate change recorded in ice cores from Greenland. They found the Atlantic got saltier during cold periods, and fresher during warm intervals.

We're probably all familiar with this theory of the ice age. Might as well get it in here though.

[Beagle]

http://www.guardian.co.uk/science/story ... 58,00.html

Nearly a third of the world's land surface may be at risk of extreme drought by the end of the century, wreaking havoc on farmland and water resources and leading to mass migrations of "environmental refugees", climate experts warned yesterday.
Predictions based on historical trends in rainfall and surface temperatures dating back to the 1950s reveal that regions blighted by moderate droughts are set to double by the end of the century, with tentative data suggesting areas struck by extreme droughts may soar from 1% today to 30% in 2100

From The Daily Grail. More dire predictions.

[Bruce]

http://www.terradaily.com/2006/06100905 ... qpvhf.html

Environmental and rights activists also called on the government to prepare to accept environmental refugees fleeing small Pacific island states hit by rising sea levels

.


Drought in one part of the world and islands getting flooded out in others. The next Asian migration begins?

[marduk]

with tentative data suggesting areas struck by extreme droughts may soar from 1% today to 30% in 2100

NOOOOOOOOOOOO
i'm gonna start panic buying Evian right away
theres been a hosepipe ban where i live for almost ten years now
if I don't act now i'll have nothing to drink by the time I'm 130

[Beagle]

http://physorg.com/news79808634.html

Scientists have found new evidence that the Bering Strait near Alaska flooded into the Arctic Ocean about 11,000 years ago, about 1,000 years earlier than widely believed, closing off the land bridge thought to be the major route for human migration from Asia to the Americas

This should help settle the issue about migration to the Americas.

[Minimalist]

http://physorg.com/news79808634.html

Scientists have found new evidence that the Bering Strait near Alaska flooded into the Arctic Ocean about 11,000 years ago, about 1,000 years earlier than widely believed, closing off the land bridge thought to be the major route for human migration from Asia to the Americas

This should help settle the issue about migration to the Americas.

The Club doesn't give up that easily, Beags!

[Beagle]

http://physorg.com/news79791441.html

Palaeontologists have long puzzled over fossil records that, remarkably, suggest mammal species tend to last around two and a half million years before becoming extinct.

Climate experts and biologists led by Jan van Dam at the University of Utrecht in the Netherlands, overlaid a picture of species emergence and extinction with changes that occur in Earth's orbit and axis.

The Earth's orbit is not a perfect circle: it is slightly elliptical, and the ellipticality itself goes through cycles of change that span roughly 100,000 and 400,000 years.

Its axis, likewise, is not perfectly perpendicular but has a slight wobble, rather like a poorly-balanced child's top, which goes through cycles of 21,000 years.

In addition, the axis, as schoolbooks tell us, is also tilted, and this tilt also varies in a cycle of 41,000 years.

These three shifts in Earth's pattern of movement are relatively minor compared with those of other planets.

But they can greatly influence the amount of radiation -- heat and light -- which Earth receives from the Sun. The effect can be amplified, causing global cooling, affecting precipitation patterns and even creating Ice Ages in higher latitudes, when two or all the cycles peak together

The elliptical orbit of the earth as a cause of climate change and extinction. From The Daily Grail.

[Beagle]

http://news.nationalgeographic.com/news ... obble.html

Small changes in Earth's orbit and tilt may have regulated the cyclical rise and fall of many prehistoric mammal species, new research suggests

Another article about the above subject - from National Geographic.