Hopefully the sun keeps it's low activity level for a decade or 2 and we can get rid of the current man-made global warming theories.

You say that we can't do anything about it... what about geo-engineering?

Geo-engineering is, at best, a last ditch effort. It's a nice concept, and I have to admit some of the ideas do sound quite apealing as a solution; but the risks involved with most geo-engineering ideas are far too high for serious consideration yet. I'd wait a few more years.

Some ideas, such as artificial carbon trees, are a low risk approach and these may be worth consideration now (even if they cost a bomb). But ideas such as seeding clouds and so on are probably not worth going for yet because they are high risk, and I think this is typical of most geo-engineering ideas.

It's something we can do about global warming if it gets too bad in the future and the risk from warming is larger than that of geo-engineering, but it's not worth taking seriously yet.

Well, one example I was thinking of was these tubes I read about somewhere.

Now, I'm not 100% sure of what they were, but they were basically big tubes that go in the ocean, vertically. Basically, they take water from the surface, and pump it to the bottom, and vice versa. The idea being that the water on the surface is usually warmer, and has a higher concentration of oxygen and carbon dioxide than the water at the bottom.

By doing this, you basically flatten out the temperature between the surface and the bottom - cooling the water on surface, and heating the water at the bottom... cooler surface temperatures of water reduce the risk and power of hurricanes, while the ocean will also be able to absorb more carbon dioxide and oxygen. The more moderate temperatures, and greater levels of oxygen also provide a better environment for marine life, helping to replenish dwindling fish supplies.

According to the book I was reading, the tubes would be relatively inexpensive (ranging between a couple of hundred million dollars, to the low billions) compared to the savings they would make: placing them in the gulf of Mexico, for example, would reduce the number and strength of hurricans hitting the south east of the USA... which costs billions of dollars each year in damages. Placing them in the Indian ocean could also reduce the effects of monsoon season in SE Asia, and also, placing them around the African coastline can actually increase the amount of rainfall that hits the African continent - perhaps helping to reverse desertfication.

The tubes would also be relatively low-risk, because any perverse effects would quickly wear down after the removal of the tubes, if unforseen weather patterns make things worse. If they are not very effective in some parts of the ocean, they can easily be moved to other places where they may have greater effect.

I personally think this is one sure-fire method of geo-engineering, and I don't see why we're not going along with it.

The major issue i see with this idea is that it would definitely kill wildlife in the ocean. A lot of creatures need a certain temperature of water to survive. Changing that could kill them.

Well, one example I was thinking of was these tubes I read about somewhere.

Now, I'm not 100% sure of what they were, but they were basically big tubes that go in the ocean, vertically. Basically, they take water from the surface, and pump it to the bottom, and vice versa. The idea being that the water on the surface is usually warmer, and has a higher concentration of oxygen and carbon dioxide than the water at the bottom.

By doing this, you basically flatten out the temperature between the surface and the bottom - cooling the water on surface, and heating the water at the bottom... cooler surface temperatures of water reduce the risk and power of hurricanes, while the ocean will also be able to absorb more carbon dioxide and oxygen. The more moderate temperatures, and greater levels of oxygen also provide a better environment for marine life, helping to replenish dwindling fish supplies.

According to the book I was reading, the tubes would be relatively inexpensive (ranging between a couple of hundred million dollars, to the low billions) compared to the savings they would make: placing them in the gulf of Mexico, for example, would reduce the number and strength of hurricans hitting the south east of the USA... which costs billions of dollars each year in damages. Placing them in the Indian ocean could also reduce the effects of monsoon season in SE Asia, and also, placing them around the African coastline can actually increase the amount of rainfall that hits the African continent - perhaps helping to reverse desertfication.

The tubes would also be relatively low-risk, because any perverse effects would quickly wear down after the removal of the tubes, if unforseen weather patterns make things worse. If they are not very effective in some parts of the ocean, they can easily be moved to other places where they may have greater effect.

I personally think this is one sure-fire method of geo-engineering, and I don't see why we're not going along with it.

First off, wouldn't messing with the temperature of the ocean in such a way be tampering with the thermohalene circulation of the oceans too much? (The circulation of salt water driven by heat). Thermohalene circulation is essential to life. If you planted one of these tubes and it interrupted the circulation of salt water causing a "shut down", then it would ravage life in the ocean, and, subsequently, us. A shutdown would happen if you made the water either too hot or too cold. It wouldn't matter if the surface temperatures were more moderate at the surface or not if this were to happen, life would die.

For completeness sake on this point it is probably worth mentioning that thermohalene circulation shutdown is also a postulated effect of global warming too, and if this were to become a serious threat, then yes, your idea might need to be implemented then to try and counteract it. But a real, real threat would need to be be posed before we even consider doing this.

Second, when CO2 dissolves in the surface water it can become carbonic acid, and this has already lead to a 0.1PH increase in ocean acidity since the indstrial revolution just from the CO2 emissions we've released into the atmosphere being absorbed by the ocean. If the ocean becomes too acidic, again it would kill life. This is what's already killing the corals. There is a natural absorbtion rate for CO2 in the ocean, and yes this does mitigate some of the supposed effects of climate change, but doing this on too large a scale could also harm ocean life on a massive scale. Going out of our way to actually make the ocean absorb more CO2 at the surface than it presently does, like you said, seems a little silly to me to say the least.