what is a global cause for sea level decrease?
475850
At times in the past, a significant portion of the world's water was tied up in the form of glacial icecaps at the poles.
584
Global warming is the theory that the Earth's atmosphere and oceans are getting warmer due to pollution and other environmental factors induced by humans.\n\nSome of the factors include burning fossil fuels (oil) and deforrestation (trees remove carbon dioxide from the atmosphere).\n\nThere's discussion that if the effects of global warming aren't counteracted, ice caps will melt, sea levels will rise, and weather patterns could be altered. \n\nLow-lying coastal cities such as Bangladesh or New Orleans could be wiped out within the next 100 years as sea levels rise. Weather patterns could be altered, bringing drought to areas that used to have lots of rain, and rain to areas that used to be arid.\n\nRead any of the sources below, and you'll find more information about the causes and potential effects. It's definitely something that shouldn't be ignored.
1000629
I think it's gonna be real cold.  Like Michigan (where i live).  But no, If it is in fact a ice age, that means that  huge amounts of water  are frozen into glaciers (and because we only have so much water on earth) sea levels will actually go down because water is locked in the glaciers.  Global warming causes glaciers to melt and hence rises sea level.  And by the way, we are still technically in an ice age (we still have huge ice sheets) we are in what's known as an inter-glacial period.  The last glacial maximum was about 22,000 years ago.  Sea levels were so low that humans could walk across dry land from Ireland to Britain then to the mainland of Europe! Check out a map!
181135
Coral reef degradation\n\nhttp://www.sidsnet.org/pacific/usp/marine/Gcrmn/GCRMN/Node2000.htm
36490
Global warming is associated with sun spots. So if the sun spots disappear we will probably have a period of global cooling but maybe not an ice age. The last period of global cooling was around the year 1650 AD.  That period is called the "Maunder Minimum".
61988
We have been able to observe that the earth has been going through a cycle of glaciation that is about 100,000 years in duration, and has extended back for that last one million years or so. We are presently recovering from one of these periods of glaciation. Here you can see a graph that shows these cycles: http://vathena.arc.nasa.gov/curric/land/global/climchng.html\n\nAs the earth's orbit changes slightly in cycles known as Milankovitch cycles, the earth begins to cool. As this cooling causes glaciers to increase in size due to less summertime melting, the glaciers themselves begin to effect climate. The glaciers reflect much more sunlight than bare rock or soil, so they accelerate the cooling effect on the planet. Other changes occur as more water is stored in glacial ice and sea level is likely to drop. This in turn has effects on the salinity of the oceans and changes current patterns in the ocean. Growth of glaciers is even believed to have effects on weather patterns like the jet stream. The effects are very complex and the study of paleoclimate is very interesting, and has much potential for discovery and understanding the changes in climate our earth is currently experiencing. \n\nAnother major effect of glaciers is caused by their weigh and the effect that accumulations of large masses of ice can have on the underlying earth's crust. Current studies using geodesy (measurements of change in elevation) of the Louisiana coastline suggest that glaciers in North America that extended as far south as southern Illinois may have even caused movement of the American continental plate that is taking place today. As these glaciers melted they removed a great weight of ice from the northern parts of the continent. This may have caused that part of the continent to rise, and the southern part of the continent to sink, much like a teeter-toter, except the rocking motion is on a 10,000 year time scale. This may be one of the reasons that Louisiana is experiencing coastal flooding and was hit so hard by hurricanes. There is still considerable debate about how large a role tectonic rebound might be playing in Gulf subsidence, but my point is that receeding glaciers can have environmental effects that extend far beyond the existence of the glacier over time. The reference for this is here: http://www.hgs.org/en/cev/?286
1082968
I read in new scientist that there there is a certain current in the Atlantic that transports hotter ocean water from the south to the north.\n\nWhat happens here is the arctic ice will cool the temperature of the water down and it will thus flow south again.\n\nWith global warming there will be a constant flow of hot water to the north thus raising the water level there. So all places on the northern hemisphere would get affected first. \n\nI'm not too sure I got all the facts right but it has something to do with a current though.
1020525
Salinity will decrease a bit, but it won't be very significant.  \n\nLower salinity fish might move out of their environments and colonize other parts of the oceans.
1128312
The weather changes will have already happened if they're enough to make the icebergs melt.  \n\nRaising the temperature of the earth 8 degrees, sea levels will rise, flooding coastal areas. Heat waves will be more frequent and more intense. Droughts and wildfires will occur more often. Disease-carrying mosquitoes will expand their range. And species will be pushed to extinction.\n\nMore and more intense rainstorms and hurricanes.  Sea level rise will result in loss of coastal wetlands and barrier islands, and a greater risk of flooding in coastal communities.
48405
Because the sea level in the pacific is different than the sea level in the atlantic. Rather than having fast rapids flowing from one side to the other (more erosion and harder for ships to navigate), they have level sections of water separated by locks.
1167911
Science explains Global warming. More storms, bigger storms, carbin dioxide levels, soon crops may burn up before they grow, rain forest desease may spread, Gulf stream may stop, In Our Lifetime.\nIs a good read, go see... Times ARE changing.
204545
I'm assuming you're asking about tectonic plate movement and not heavier stuff like the earth tilting on its axis. The first link shows a map of the earth currently and how it's moving so you can figure it out on your own.  The second link gives your the answer to your question.  It shows the Pacific Ocean getting much narrower.
116177
The ocean currents are a major factor in the climate of this planet. Many regions experience weather patterns and temperatures that are related primarily to the effect of ocean currents. Other weather patterns like hurricanes and El Niño events are also strongly affected by ocean currents.\n\nOcean currents in the Northern Hemisphere circulate in clockwise patterns around the basins. These are known as gyres. The Gulf Stream which moves northward up the western side of the Atlantic Ocean basin is responsible for moderating and warming the climate of Ireland, England, and northern Europe. The equatorial currents that move westward across the Pacific Ocean are an intrinsic part of the climate patterns known as El Niño and the Southern Oscillation. This climate pattern effects North and South America, Australia, India, eastern Asia, and even parts of Africa. Even Western Europe can statistically relate flooding events to El Niño. In years when El Niño is active hurricanes in the Atlantic have been found to be less active. \nhttp://typhoon.atmos.colostate.edu/\n\nOne scientist proposed that sub sea eruptions along the East Pacific Rise might be creating large volumes of rising heated water that would periodically mess up the ocean currents and cause the changes of weather patterns associated with El Niño/Southern Oscillation events. Another scientist attempting to verify this discovered that the El Niño events actually precede swarms of seismic activity in that area, and suggested the El Niño may actually be triggering the sub sea volcanic eruptions by slight changes in sea level and water pressure over the mid-ocean ridges. \nhttp://ess.geology.ufl.edu/usra_esse/ENSO_Oceans.html\n\nAnother important ocean current circulates deep in the oceans and actually moves through each of the world’s oceans in a continuous slow-moving belt known as the Conveyor. This is driven by cold, salty, North Atlantic water that sinks and moves southward to the Antarctic, where it moves eastward into the Pacific, and then northward to the North Pacific, where it turns and moves back through the Indian Ocean and toward the North Atlantic again.  It is estimated that if the Conveyer were to shut down, the North Atlantic region would be 20 degrees F. colder within ten years, and much of Europe would have a climate more like northern Norway has today.\nhttp://www.columbia.edu/cu/record/23/11/13.html
3050
In order to show a measurable effect, the water bodies have to be really large in East-West expansion. Inland seas like the Baltic Sea have little discernible Lunar tide, less than a decimetre, and much less than "wind tides" which can easily change one metre.\n\nTides are caused by the gravitational pull of the moon. The entire water body alters its surface in reaction to the pull, on a much larger scale than the ground does. (Yes, that's true: the ground reacts to the moon by slight lifting and falling, too.)\n\nThe more east-west-distance is available, the more water will contribute to the changed equilibrium. The farther away the shore is, the deeper the new curve of the surface will intersect with sea ground level.\n\nReally high tides occur in funnel-shaped sections of the coasts where the wave is contracted from the sides.
510967
It is the area of land that is underwater for half the day and above water the other half. This is caused by the rise an fall of sea levels due to high and low tides.
969973
Atmospheric pressure at sea level is caused by the weight of the atmosphere pushing downward. (weight /area).\n\nIf you approximate the Earth as a sphere, calculate the surface area of the sphere, and then multiply the pressure times the area you will get an approximation for the weight of the atmosphere.\n\nStandard pressure is 100 kPa. \nThe Earth's equatorial radius is roughly 6400 km\n\nSurface Area of a sphere is 4*pi*r^2 = pi*d^2\n\nMass = A*P
946410
actually that's not correct.. because it is at a stasis (not all of it is under water) the melting of an iceberg would have 0 effect on ocean level, positive or negative.. it's the glaciers melting that are over land like at Antarctica that would cause the change, and they would drown most of the coastal US.\n\n\nhah, i wasn't trying to make a political statement about it... in all honesty my personal belief is that the natural cycle is much stronger than anything we can do and would find a way to balance itself out... but sure, if you wanted to harvest some water send someone to chip away at a glacier.. it's all the fresh water anyone would need for hundreds of years lol.. of course there would be pro's and con's for that.. but that's for the philosophers to debate.  I don't mind my hill top becoming beachfront.. but a few billion people might disagree with me.